cool battery experiments

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STEAM Project: Tiny Dancers (A Homopolar Motor)

March 10, 2015 by Ana Dziengel 71 Comments

Today we are getting a bit artsy with our science! Does the idea of making a wire sculpture that “dances” entice you……? Tiny Dancers is the third project in our collaborative series STEAM POWER: Empowering kids to explore the world through creative projects. Today’s topic is HARNESS!

This post contains affiliate links to products I love and recommend to my readers.

SAFETY NOTE:

Neodymium magnets are extremely strong and MUST BE KEPT OUT OF REACH OF SMALL CHILDREN! Do not give them to any child who might put them in their mouth, they are dangerous if swallowed and must be surgically removed! This is a project for older children who can understand the precautions and I recommend ADULT SUPERVISION! For more about neodymium magnets safety and precautions go here   Additionally neodymium magnets can interfere with electronic devices so please keep them away from phones!

Also please note that these motors do heat up. See our TIPS section for safety precautions.

Tiny Dancers (A Homopolar Motor)

Note: Before we get started I want you to know that despite this looking very easy there is a fair amount of TWEAK TIME you will need to invest to make this project work! I recommend starting with a BASIC HOMOPOLAR MTOR to get the hang of how the motor actually works, then trying your hand at making a tiny dancer. Each dancer will need to be tweaked to get them to dance properly on a battery. Don’t be discouraged if at first it doesn’t work, keep tweaking and see our tips sections for some troubleshooting solutions.

download our template here

• Copper Wire- THIS is the gauge we used
• 1/2″ x 1/8″ Neodymium Disc Magnets
• 3 in 1 Combination Tool or pliers/wire cutters
• Crepe Paper (optional for skirt)
• Hot Glue (optional)

Instructions

• Steps One Cut a long piece of wire off your spool, I started with about a 10” long piece. Lay it on the template of your choice and bend as shown using  3-in 1 tool or pliers. No need to be perfect HOWEVER try and keep your form as symmetrical as possible.
• Step Two To create the base section of wire that wraps the magnets, I recommend bending the end of the wire around the battery. Remove the battery and gently widen the circular wire form with your fingers.
• Step Three Place three neodymium magnets on the negative side of your battery.
• Step Four Place the motor on top of the battery so that it touches the positive pole. The round section at the bottom of the motor must be low enough to encircle the magnets!
• Step Five Let it go. If properly constructed it should start to spin. If it doesn’t see our tips below.
• Step Six (optional) to make a skirt for your dancer cut a small circle of crepe then cut a slit in the center of the circle. Slide it up onto the dancer and secure in place with a dab of hot glue.
• MONITOR THESE FOR HEAT!  Some of the motors that got going really fast heated up quite quickly. If you notice a battery getting usually warm stop the project, let it cool down and remove the magnets. I recommend against reusing a battery that got overheated.  Instead replace it with a fresh battery. One educator warned me about a defective battery that peeled open during this experiment. Please monitor the motors closely as they spin.
• Start with your basic homopolar motor. It’s easy to bend and shape and you should have success with it. The dancers require more time to fine tune.
• Keep the forms as symmetrical as possible! Since they spin on an axis if the are not symmetrical and/or balanced they will spin off the battery! This happened to us all.the.time. If they do spin off try and bend the form slightly to get them balanced on the battery.
• To make the head of the dancer, bend your wire around a pencil.
• Thin wire does not work! We tried this with very thin copper wire at first and it did not work. Stick to heavier gauges. Here is the gauge we used.
• The templates are meant as GUIDES ONLY! The motors will need to be fine tuned by hand by you!
• Remove the magnets immediately after running your motor. They will drain your motor if kept attached.
• When the electrical circuit is completed you will hear a very low buzz.

Troubleshooting

• If the motor does not work try turning your magnets  upside down and reversing the polarity . I found this did the trick most of the time.
• The batteries burn out quickly! If turning the magnets upside down doesn’t work, try replacing your battery with a new one.
• Make sure that the bottom section of wire encircles the magnets. If it doesn’t your motor will not work.
• Be sure your wire is free to move around the battery and magnets. If it’s too close to the battery or magnet it will get stuck and be motionless.
• I read that you can use a nail to put a small indentation in the top of your battery to help keep the motor in place. I highly recommend AGAINST doing this . I tried it! One small and light dent worked and the next dent smashed a hole in the battery causing battery acid to spin on my counter! Eek! I decided off balance motors were better than battery acid splashes.

What’s happening?

I’m going to keep this as simple as possible because let’s face it, electromagnetism is hard to explain! Basically homopolar motors demonstrate something called a Lorentz Force . This is a force that is generated when electricity moves through a magnetic field. Our copper wire is conducting electricity from one end of the battery to the other. As it moves through the magnets on the negative side of the battery, it creates a force which causes the wire to spin .

You can read more about the Lorentz force and homopolar motors  here  and here .

Hendrik Lorentz. Hendrik Lorentz was a Nobel Prize winning Dutch physicist who inspired Albert Einstein! The Lorentz Force is named after him though he was not the first to discover its existence. In his early years Lorentz was primarily interested in studying electromagnetism and light. Albert Einstein used Lorentz’s paper “ On the Electrodynamics of Moving Bodies “ as the basis of his own work and the theory of special relativity. It’s super complex stuff but suffice it to say Lorentz ‘s studies of electromagnetism laid the groundwork for some of the most important scientific discoveries of the last century.

Ready for more projects that harness energy?

My fellow bloggers have done a wide variety of projects you have to check out!

Simple Circuit  – What Do We Do All Day

Rubber Band Car  – All for the Boys

Lego Inspired Electric Dough  – Lemon Lime Adventures

Design Thinking  – Meri Cherry

Mason Jar Solar Night Lights  – Tinkerlab

Electromagnetic Train  – Frugal Fun For Boys

10 Ways to Play & Learn with Springs  – Left Brain Craft Brain

If you are looking to incorporate more STEAM ideas into your family’s creative day check out our STEAM Kids Book

Fill your child’s life with more art, design, science, and engineering.

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March 10, 2015 at 7:06 am

Well…. that is pure awesomeness!

Ana Dziengel says

March 10, 2015 at 9:32 am

Thanks Mama!

Jillian Burt says

May 15, 2016 at 2:46 am

Rachel says

December 12, 2016 at 6:57 pm

ok, i am in 5th grade and I’m doing the tiny dancers for my science project. THIS IS SO COOL!

December 14, 2016 at 6:44 am

March 10, 2015 at 8:51 am

Love the combo of adorable dancers and battery power! My daughter just gave the highest compliment: “I want to do that! Now!”

Meri cherry says

March 10, 2015 at 10:02 am

You just blew me away.

March 11, 2015 at 7:01 am

These are adorable, Ana. Just adorable!

Rachelle | TinkerLab says

March 11, 2015 at 6:07 pm

I love the simplicity of this (and yet, it seems quite complicated). Brilliant, Ana.

March 25, 2015 at 6:02 am

Thank you so much Rachelle!

Cait Fitz @ My Little Poppies says

March 19, 2015 at 12:25 pm

This is AMAZING. I cannot wait to try this with my STEM-obsessed little dancers. Thank you so much for sharing. The video was incredible, too, by the way! Nicely done!!

March 25, 2015 at 5:58 am

Thank you so much Cait!

Mariana says

March 20, 2015 at 5:22 pm

What a great idea!

March 25, 2015 at 5:57 am

Thanks Mariana!

Leslie says

March 23, 2015 at 11:39 am

These are so cool! 🙂 Love how they look like they’re dancing!

March 25, 2015 at 5:55 am

Thanks Leslie!

March 25, 2015 at 6:04 am

I see you have a link for the magnets, but do you have any ideas of where I might be able to find them locally? (Or type of store that might carry them?) Thanks for the great idea! My kids can’t wait to do this activity!

March 25, 2015 at 6:13 am

Possibly Radio Shack or an electronics store but they usually stock only ceramic magents which are not strong enough. Call ahead and see!

Sallie says

April 26, 2016 at 12:53 pm

Do you think ferrite magnets might work? I am having a hard time paying $20 for neodymium magnets!

April 30, 2016 at 4:07 am

Hi Sallie, I’m not sure but magus is they will not work. They just don’t have the power of neodymium.

Meghan @ PlaygroundParkbench says

May 31, 2015 at 7:45 am

Planning a ballerina-themed birthday for my oldest this summer… these will make the cutest centerpieces. Do you think they would work with a bigger battery too?

June 5, 2015 at 6:00 am

They are pretty finicky so I’d stick with the small battery. Plus these babies get got after spinning awhile so take precautions if experimenting with a larger battery 🙂

Jennifer says

June 6, 2015 at 8:37 pm

What guage wire did you use?

June 23, 2015 at 4:45 am

16 Gauge. Here’s the product we used: http://amzn.to/1BJcthJ

November 17, 2015 at 12:06 pm

Sorry to keep pestering–that link is broken too! I’m not sure where to buy the battery?

November 19, 2015 at 4:17 am

No prob! Here is a link 🙂 http://amzn.to/1S6bawG

Tracy Hart says

June 10, 2015 at 9:18 pm

The link to buy the magnets is broken. Could you tell me which size I should order off Amazon.

June 23, 2015 at 4:40 am

Thanks for letting me know! Here is the link : http://amzn.to/1CqrBeF

Shannon says

June 29, 2015 at 12:05 pm

This is not working for us. I tried all of your troubleshooting tips but no luck. Any ideas?

July 18, 2015 at 6:07 am

Sorry I’m just seeing this Shannon! Did you get it to work? I’m happy to help you troubleshoot if you still need it. Email me at [email protected] .

Shanna Taylor says

July 2, 2015 at 9:35 am

What size are the magnets that you used? I am figuring out that they are not easy to find. Thanks!

July 18, 2015 at 6:05 am

1/2″ diameter x 1/8″ thick. They are best ordered online 🙂

Bridget says

July 7, 2015 at 5:54 pm

How long approximately would an AA battery last if they dance non-stop?

July 18, 2015 at 6:00 am

I’m not sure. Ours burnt out after a day or two of use but we didn’t have them running non stop. I probably wouldn’t leave them running indefinitely as the battery gets hot. They should be run with supervision.

Elizabeth says

July 17, 2015 at 6:59 am

Can you put another link to the magnets? The link is no longer working. Thank you

July 18, 2015 at 5:59 am

Thanks for letting me know! The link has been updated 🙂

Kenan okan says

September 16, 2015 at 9:01 pm

deneyi yapıyordum ama sizinki daha güzel. Teşekkür.

October 19, 2015 at 6:56 pm

Can you use Bare Copper 16 Gauge Artistic wire?

November 9, 2015 at 9:17 am

I believe that should work 🙂

October 20, 2015 at 5:02 am

Awesome article!! The magnets are available at all Michael’s craft stores, and I believe A.C. Moore also carries them. Cool!!

November 9, 2015 at 9:16 am

Good to know!Thanks!

November 18, 2015 at 6:11 pm

This project was done at my school and me and my class mates loved it

November 19, 2015 at 4:04 am

I love hearing this Lena!!! It makes my day!

Catherine Stephenson says

November 22, 2015 at 1:09 pm

I absolutely love this science project idea. The fact that it is tailored to little girls I think makes it more attractive for them. These type of projects can often be more of boy interest. Keep it up!

November 24, 2015 at 7:34 am

Thank you so much for the encouraging words!

Kimberly says

January 13, 2016 at 6:15 am

January 16, 2016 at 5:16 pm

Do you have to use that size disc battery or can you use a little bigger one? The next size up is all I can find on amazon. The link posted for the magnets, is not secure for credit card. My pop up security feature came up when I tried to order there. 🙂

February 23, 2016 at 7:46 am

what age group do you think this is for? my daughter in middle school and is doing this for her school.

Levent Suberk says

February 29, 2016 at 4:00 pm

Thanks for this article. You wrote that “If the motor does not work try turning your magnets upside down and reversing the polarity.” But this only reverse the motion of wire, it does not affect working.

project centre says

March 10, 2016 at 2:09 am

Awesome job with batteries. That looks great. Thanks for your idea

March 18, 2016 at 2:33 pm

Thank you for this! Is there a way this project can be done for a class of students at a lower cost? IE: Would smaller batteries/magnets/wire have the same effect?

Hallo Bloggi says

April 4, 2016 at 1:55 am

Awwwwww!!!! Great idea! Thank you. Bloggi

April 8, 2016 at 4:59 am

Veronica Marino says

April 19, 2016 at 3:00 am

We had a big problem doing this activity. I used supplies [magnets, wire] from the sources you cited and duracell batteries. I first had the students shape the wire and then gave out the batteries, waiting to put the magnets in place only at the very end. After about 2-3 minutes more than one pair of students noticed the batteries getting warm, one very much so–and that battery actually peeled open and we had to shut down the activity! I think it was a defect with the battery, but I thought I should highlight this for other users/educators so that they know that the batteries need extreme caution and that in general this is an experiment with a high degree of caution

April 19, 2016 at 2:23 pm

Hi Veronica, Thank you for sharing your experience. I do have a warning in the post that these heat up and I appreciate you bringing it up again in your comment. I did this project many times without an issue of a battery peeling open though some batteries did get warm over time. I will add an additional note about your concern. Thank you, Ana

Jacquelyn says

April 25, 2016 at 7:06 pm

Put a small nut on top of the battery and the dancer will stay centered. I lost my patience with trying to tweak it!

April 30, 2016 at 4:04 am

Thanks for the tip!

Ana Rodz says

April 29, 2016 at 8:24 pm

We are doing this project for my son’s science fair. The hardest thing was finding the magnets we found a good deal on ebay. And instead of tiny dancers we are doing rockets and airplanes. Let’s see how bit goes. Thanks for the step by step video

August 16, 2016 at 4:29 am

Rockets and airplanes sounds great! I hope it was a success!

May 27, 2016 at 2:51 am

Amazing post Ana!!! I appreciate your talent. Here you described step by step procedure. I really love the dancers and the battery power. Keep up…

May 30, 2016 at 7:11 am

At first, I was like this is the perfect project for STEM , I’m going to do this… Then when it said all the negative and dangerous things about the battery I’m still confused should I do it or not?

August 15, 2016 at 8:34 am

It’s great for older kids. Anyone that tries it should be aware of the potential safety concerns which is why I have added the Safety Notes.

July 3, 2016 at 5:15 pm

Thank you for sharing, we have not yet success in getting it work….

July 8, 2016 at 8:00 am

I’m sorry to hear that Koko. Have you checked out our troubleshooting section?

Rafaella says

August 20, 2016 at 9:08 am

I need photos of the steps, but i don´t know in were can i found it!!!

Anyway thanks for the experiment!!

August 21, 2016 at 12:42 pm

Hi Rafaella, What steps are you looking for images for? Ana

Diana @ Toys for kids says

October 4, 2016 at 2:18 am

What a great idea! This is awesome! Thanks for sharing this creativity. Amazing post!

October 31, 2016 at 12:41 pm

Yay! Glad you liked it!

Louise says

November 30, 2016 at 8:02 pm

I love your ideas here and I wanted to use one of your activities for a school assignment, how would I be able to reference you in APA format?

December 9, 2016 at 5:38 am

What is APA format?

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• 5 Battery-Powered Science Experiments to Try After School
• After School Activities

Share This Activity

Batteries come in all shapes, sizes and compositions. And while they often go unnoticed, these small, handy power packs provide a steady supply of electrical energy that powers some of life’s most essential items.

Batteries come in all shapes, sizes and compositions.

And while they often go unnoticed, these small, handy power packs provide a steady supply of electrical energy that powers some of life’s most essential items.

The different types of batteries include:

• Household batteries (rechargeable and non-rechargeable). These are the most common types of batteries that power things like cell phones, toys and hearing aids.
• Industrial batteries. These batteries exist to power heavy-duty systems like machinery, railroad and telecommunications systems.
• Vehicle batteries. These are large, yet fairly easy to use. And they power our cars, motorcycles, boats and other motorized vehicles.

What’s the science behind batteries?

In a nutshell, a battery slowly converts chemicals packed inside it into electrical energy, or electricity. That energy is typically released over a period of days, weeks, months or even years.

The electricity is produced through an oxidation/reduction reaction which occurs when electrons are transferred from one substance to another.

5 Battery-Powered Science Experiments to Try In After School

In honor of National Battery Day, we’ve rounded up a few of our favorite battery-powered experiments for students to try after school.

*These activities require adult supervision. While most are designed for older students, younger students may participate and will enjoy watching the experiments.

Make a Lemon Battery

Create a battery out of lemons that produces enough energy to power a digital clock!

• 4 galvanized nails
• 4 pieces of copper
• 5 alligator clip wires
• A small digital clock to power up

Visit Chrome Battery to see the full experiment.

Electrolysis of Water

Use the energy from a 9V battery to separate liquid molecules (hydrogen and oxygen) to create even more energy. As a result, the energy produced will literally split the water! In this experiment, students will test to see which water solution is the best conductor of electricity.

• Distilled water
• 2 silver-colored thumb tacks
• Small, clear plastic container
• 2 test tubes
• Baking soda
• Dishwashing detergent

Visit Education.com to see the full experiment.

Which Battery Lasts the Longest?

This experiment explores the difference between alkaline and non-alkaline batteries. Students will also determine which type of battery lasts longer: brand-name batteries or generic brands.

• Several different brands of AA batteries. Try to purchase batteries that all have roughly the same expiration date (at least within the same year), and note the price you paid per battery. Here are some suggestions:
• Brand-name batteries (Rayovac, Energizer, Duracell, Eveready and Panasonic)
• Generic brands (CVS, Walgreens, Rite Aid and Kirkland/Costco)
• Several identical flashlights that take two AA batteries (get one flashlight for each type of battery you plan to test)
• Clock or watch
• Masking tape (for labels)

Build an Electric Motor

Harness the power of one AA battery to build an electric motor that spins!

• One AA Battery
• Copper Wire (18 gauge should work)
• A neodymium (rare earth) magnet
• Wire cutters
• Needle-nosed pliers

For the optical illusion version:

• Colored pencils

Visit Frugal Fun for Boys and Girls to see the full experiment.

Dirt Battery

This experiment doesn’t involve an actual battery. But it uses ordinary items and materials, like dirt, to build a makeshift battery that can power a little LED light!

• Ice cube tray
• Galvanized steel screws
• Copper wire
• LED pin Lights

Visit Teach Beside Me to see the full experiment.

Batteries are small power packs that make it possible for cell phones, medical devices and other essential technologies to exist. Use these battery-powered science experiments to help students explore the magic of batteries after school.

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4 Shockingly Simple Battery Experiments

How many pumpkins would it take to power a lightbulb? We don't know, but we want you to find out! These simple experiments make great elementary science projects, and are a fun way to teach your child the basics of conductivity and electricity. Turn two pumpkins into a low voltage battery, measure the conductivity of a lemon, use graphite and paper to create a closed circuit, or power a timer with a stack of pennies! 

(Ages 9-16 )

Learn about electrochemical cells and make a battery using pennies, felt, and a salt water solution. Then, power a digital clock with it!

Can you complete an LED circuit using a graphite pencil? Learn about the conductive properties of graphite and draw your own design to see it light up! This is a super quick and easy science experiment that is entertaining for both kids and adults alike.

Discover even more about the power of electricity and light with Levitating Lantern from the KiwiCo Store ! Build a lantern that floats above its base with the help of tension and rubber bands!

(Ages 5-16 )

Harness the power of pumpkins with a pumpkin battery and see how many volts it can produce! 

Learn how to make a pumpkin battery!

(Ages 5-11 )

The potato battery is a classic but did you know that you can also make a battery out of a penny and lemon? In fact, there are a bunch of household items that can be made into batteries! In this project, we test a penny and lemon to see how many volts it can produce!

Get DIYs like this delivered to your inbox!

Get inspired.

Build A Potato Battery – a Circuit STEM Activity for the Science Fair

We love our STEM Activities . As a child STEM wasn’t a thing in my world, but you know what was big? The science fair! Now that we homeschool, I love challenging my children to explore science the way I used to at these fairs. So we decided to tackle a project that is a little more earthy, building a Potato Battery .

Disclaimer – This post contains affiliate links

Potato Battery – An alternative energy source? 

What you will discover in this article!

One of our interests is alternative energy sources. In the past we have explored wind power and solar power  in our homeschool, but this time we thought it would be fun to try something different. A few months ago we watched a story out of about some research being done at the Hebrew University of Jerusalem . They had discovered a way to create enough power to light an LED bulb with a potato!

Now circuit building is a big thing around here, we’ve built so many different circuits over the years. Not once, though, have we used food. It was time for a new challenge!

Supplies to build a Potato Battery

Potatoes – We used large Russet Potatoes Zinc Plates Copper Plates Electrical Tape Alligator Clips and Wires LED light bulbs MultiMeter

You will also need a stove top, water, and tongs.

How to Build a Potato Battery

The process of building the potato battery is relatively simple but will involve some investigation and testing. Just like any great experiment.

Start by slicing your potatoes lengthwise into approximately 3/4 inch wide strips. Boil the potatoes for 8 minutes. Do not over boil, you need the pieces to remain firm. Remove from water and let cool.

Tape a zinc plate to the bottom and the copper plate to the top of one slice of potato. Leave enough of the plates at the ends so you can attach the alligator clips. Take a voltage reading with the multimeter.

A single slice from our potato produced 0.88 volts! How cool!

Now put together more slices so you can build a battery cell.

To connect each cell to the next you need to connect them the same way you would batteries, positive to the negative. Or copper to zinc. So on the first slice attach the lead to the copper, then attach the other end to the next slice on the zinc plate. On the second slice attach a lead to the copper plate, then attach the other end to the zinc on the third slice. Continue this across your pieces until they are all connected. You will notice that the zinc on the first slice is not connected to anything, and the copper on your last slice is not connected to anything.

Here is our final wiring with black leads added to the free plates.

Now attach leads to those end pieces and take another reading on the multimeter. You can even do these readings as you add each cell to see how much extra power each cell is adding to your potato battery. We did 5 cells and ended up producing 4.35 volts!

As a comparison we tested two AA batteries and they only produced 3.2 volts.

Now the big test, attach the leads to your LED and see if you can get your bulb to light up.

We lit up a light bulb with potatoes!! How cool is that?

Potato Battery – The Science

The idea of creating a battery from potatoes is such a cool idea, but we definitely had to do some research to understand the science.

In each cell a chemical reaction is happening between the two metals and electrolytes which transport charged particles called ions. In our project, the copper and zinc are our metals – functioning as our cathode (+ terminal) and anode (- terminal) and the potato is providing the electrolytes.

When we hook up our potatoes to the multimeter or LED,  electrons are transferred along the wires to create power.

For a really in depth look at electricity science, this is a great resource at How Things Work .

Want to learn more about the chemical reaction between zinc and copper? Check out this video.

The reason for boiling the potato is that it breaks down the resistance and allows it to conduct the electrolytes more freely. We tested both boiled and raw, and recorded an approximately 15% increase in voltage.

Potato Battery – The Challenges

The research from the university said they could power a light bulb for a month, and the description made it sound like it only required one cell to work. We found there was no way only one cell would power our LED. It was only once we had 5 cells that we generated enough power and even then the bulb was not as bright as when we attached it to our AA batteries. We also found that it wouldn’t light certain LEDs and we never could figure out why. We are planning on returning to this activity and testing more variables. This is one science fair activity that could include a lot of depth and complexity. We feel like we’ve barely scraped the surface of our studies on this topic.

The Next Food Battery Challenges

We had so much fun building our Potato Battery we decided to try our hand at building a Lemon Battery. It was a great way to compare using different foods in this science experiment to power a light bulb. So which was better, a potato batter or a lemon battery? Check out our Lemon Battery Science Experiment to find out!

After success with our Lemon Battery, we made a Pumpkin Battery ! This is a fantastic fall project you can do with all types of Squash.

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3 Powered Up STEM Projects For Kids Using Batteries

This shop has been compensated by Collective Bias, Inc. and its advertiser. All opinions are mine alone. #PowerYourSummer #CollectiveBias

Kids love to create, and summer is a perfect time to work on all those fun STEM (Science, Engineering, Technology, and Math) projects you haven’t had time for during the busy school year. These STEM activities can also help prevent the summer slide and keep your kids learning during the summer. STEM projects for kids are infinitely more fun with interactive elements like electricity. However, electricity can be a complicated element, and even a little scary to work with, especially with younger kids. When kids are working with power, you want to make sure the projects will be safe.

We went to Walgreens to pick up some  Energizer ® Ultimate Lithium™ batteries to power up our STEM projects. The main reasons we picked  Energizer ® Ultimate Lithium™ batteries are because they are lighter than regular batteries, which is especially helpful for these projects when weight could be a factor in making the project fail. The  Energizer ® Ultimate Lithium™ batteries also have leak resistant construction, which is definitely important when you are working with them in these kinds of STEM projects. You can learn more about Energizer ® Ultimate Lithium™ batteries on the  Walgreens website

The  Energizer ® Ultimate Lithium™ batteries can be found with the rest of the electronics near the front doors of the Walgreens store we go to in Lehi, Utah.

From now until 6/30/2018, you can earn 5,000 loyalty points when you buy an 8 pack or larger of Energizer ® Ultimate Lithium™ batteries with Balance Rewards at Walgreens. The Balance Rewards program is free to join and you can do it in-store, online, or by downloading the Walgreens App. The program allows you to earn points every time you shop and turn points into dollars off future purchases.

STEM projects for kids #1: Buzzy Bug

Buzzy Bug is probably the most creative of all of these projects. Once you have the basic parts in place you can decorate it with all sorts of materials. Ours spins in a circle because of the large tail attached to the motor. If you use something smaller your bug will move differently. You can unfold the paper clips to make more stable legs with feet, or use many different materials for legs. After my daughter created her bug, she named it “Bubble Butt”.

This project will allow your kids to let their creativity fly. It also teaches science concepts like balance (to make sure the bug can stand on its own), and how electricity moves through a battery to power an object. All of these projects will teach the second concept.

Materials Needed:

• 1  Energizer ® Ultimate Lithium™ battery
• 1 small piece of foam board
• 1 small cork or another form of offset weight
• 2 small covered wires
• decoration materials (eyes, poms, pipe cleaners, etc)
• hot glue gun and glue sticks
• thick electrical or duct type tape

Instructions:

Step 1: Cut a small piece of the foam board that will fit on the motor. Use the hot glue gun to glue the motor to the small piece of foam board.

Step 2: Glue the  Energizer ® Ultimate Lithium™ battery to the foam board. Attach a cork or another kind of material to the motor that will not spin evenly as an offset to make the bug “buzz” when attached.

Step 3: Twist one end of each wire to the motor.

Step 4: Cut a small piece of tape and take one of the wires and tape the other side to one end of the battery (doesn’t matter which one, but I prefer to tape it to the positive side to make a nose)

Step 5: Cut another small piece of tape and attach it to the other end of the wire. Touch it to the other side of the battery to test the motor. Keep this wire off of the battery to complete the project. You will use this as your on/off switch. Attach to the battery when you want your bug to buzz, and remove when you want it to stop.

Step 6: Use hot glue or tape to attach legs to the motor. Then decorate the rest of your bug however you prefer. You can add decorations to the offset weight (we used a small cork) to make it buzz or spin differently. The offset weight is the main factor in how the bug will move.

Step 7: Once the bug is decorated, let it dry for a little while and then use the wire and attach it to the other end of the battery to turn your bug on and watch it go!

STEM projects for kids #2: Propeller Car

The propeller car is a really fun project that teaches how wind moves through an object to move it forward (Newton’s Law of Motion). You can also use it to teach your children how weight can slow down an object and removing weight can speed it up. The kids can also decorate the car however they want, and use different objects to see which one would be faster, then do races with the finished STEM projects.

• 2  Energizer ® Ultimate Lithium™ batteries
• 1 battery pack
• 1 propeller (usually comes with a motor)
• 1 empty can or bottle for car body
• 4 round objects for wheels (I used large opening bottle caps from sports drinks)

Step 1: Use the pointy end of the skewer to poke a hole in the round objects. If the object is too thick, you can use a drill. Move “wheel” down the skewer until it is the correct distance from the end. Use the empty can or bottle as a guide to judge how far away it needs to be.

Step 2: Cut a piece of the straw to fit the distance between each wheel. It should have a little bit of space between each wheel, so don’t cut it exactly the distance.

Step 3: Add the straw to the skewer, and then add the second wheel. Cut the extra pieces of the skewer off so they aren’t poking too far out of the wheels.

Step 4: Repeat steps 1-3 for rear wheels

Step 5: Tape both sets of wheels to the can or bottle. Be sure not to tape where the skewer is, only tape where the straw covers the skewer.

Step 6: Attach the wires from the battery pack to the motor by twisting the ends onto the motor.

Step 7: Attach the propeller to the motor, and then tape the motor to the body of the car. Make sure not to obstruct the motion of the propeller.

Step 8: Place the batteries in the battery pack, leaving one battery slightly out on one end (pushing the battery in and pulling it out will be your on/off switch). Tape the battery pack to the car leaving space for you to push the battery in and take it out when necessary.

Step 9: Push the battery in and watch it go!

STEM projects for kids #3: Scribble Bot

A warning on the scribble bot is that it is the hardest of the projects to control once the batteries are in place. Make sure you have a large sheet of butcher paper or run the bot outside or in the garage where it won’t matter if it leaves the paper. You can experiment with weights and offset sizes to see how they affect the patterns the bot will follow.

• 1 offset weight object (cork, glue stick, etc)
• 1 cylinder (plastic cup, can, cardboard roll, etc)
• rubberbands
• butcher paper

Step 1: Attach battery pack to the motor by twisting the wires onto the motor. Tape or glue battery pack or motor to the top of the cylinder. Make sure not to obstruct the part of the motor that spins.

Step 2: Use glue (super glue or hot glue) to attach the offset to the motor. We like using different sized corks for offsets since you can poke the end of the motor into the cork.

Step 3: Use rubber bands to attach the markers around the cylinder. The caps of the markers should be placed below the bottom of the cylinder.

Step 4: Place the bot on the butcher paper and remove the caps to the markers.

Step 5: Place the batteries into the battery pack. To turn it off, simply remove one side of one of the batteries. Good luck catching your bot to get the battery out though, it moves FAST!

Let’s see what YOU create!

Through these fun STEM projects for kids, your family can learn so much about how physics, electricity, and gravity work. It also gives them a chance to get super creative as they decorate their new STEM projects. Your children will also get a chance to experiment. These basic STEM projects for kids have so many variables, you can keep making them with different materials and decorations and have completely different results!

If you do make some of them, make sure to share it on social media with the hashtags #PowerYourSummer and #FTZ so I can see your projects!

This post may contain affiliate links, which means I receive compensation if you make a purchase using the links.

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Sarah Werle Kimmel

Sarah Werle Kimmel is a digital parenting coach and family tech expert. She has spent the last 20 years of her career working as a Microsoft Certified IT Manager supporting over 100 small businesses. During that time she started Family Tech LLC to help families understand and manage the technology in their home. She has regularly appeared as a family tech expert on local NBC, CBS, ABC and FOX news affiliates, BYUtv and Studio 5, and has been invited all over the world from tech companies like Lenovo, Verizon, Microsoft, Dell, and Samsung. Find out more on her website SarahKimmel.com

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Fun Lemon Battery Science Fair Experiment for Kids

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We all heard of making lemonade out of lemons and that when things go wrong, if you know to Think in The Right Way then you can make something good come out of a sour situation. But how can you make a BATTERY out of Lemons?!

Most of us know what Lemons look like; A Lemon is a yellow, oval, thick skinned and fragrant citrus fruit said to originate from India and is commonly grown in the Middle East .

Lemons are a good source of Vitamin C, which is important to boost our immune system in order to fight sickness. Lemons are used in aromatherapy, but they are not just healthy for you, they are also used for culinary purposes; lemon juice, lemon cakes, lemon cookies, a tarty lemon pie, lemon ice cream and in food preparations like Tahini, Hummus, salads and many other dishes in many countries around the world.

Lemons can also provide a lot of fun for your kids, even if they hate drinking lemon juice. One of the interesting things you can do with your kids and a few lemons, is a fun lemon battery science fair experiment ! It is an easy, low cost and fun educational activity to do at home or at school. Try this fun lemon science experiment with your kids to teach kids about electrical circuits!

How to Make a Battery from Lemons

What you need for the Lemon Battery Science Fair Experiment:

5 Easy Steps to Make a Homemade Lemon Battery:

TIP: The power from one single lemon will not be strong enough to light a bulb or be used as a battery. You will need to connect several lemons together with metal wires for enough power or electricity to light a bulb from a lemon battery. Minimum two lemons will create a battery but 3 are better. See what happens if you add more lemons. What will the volt meter show? How strong will the bulb glow?

Fun Facts about Lemons

Lemon battery science fair experiment video for kids.

Here’s a great video for kids on how to make a battery from lemons:

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Science project, how to make a lemon battery.

Has your flashlight ever stopped working because the batteries were dead?  It’s no fun walking around in complete darkness. Batteries are everywhere—in our toys, in our cars, in our flashlights and cell phones. But how do they work? What makes them stop working? You can learn how to make a lemon battery to learn more about these very important devices.

How does a battery work?

• A lemon, or other citrus fruit
• 18 (or smaller) gauge copper wire
• Wire stripper/clipper
• A grown-up or older friend
• Steel paper clip, small galvanized nail (one that is covered in zinc), or a piece of zinc (ideal)
• Ask your grown-up to use the wire strippers to first strip about 2 1/2 inches of plastic insulation off the copper wire. Then, request that the grown-up clip that piece of stripped wire off of the main roll.
• Carefully straighten the steel paper clip. Use the wire clippers to cut it to the same length as your copper wire. 
• Use the sandpaper to rub out any rough spots in your wire or paperclip. You are going to be touching the wire ends to your tongue, so you want them to be smooth. If you are using the zinc covered nail or piece, scratch it lightly with the sand paper to expose a fresh surface.
• Roll the lemon gently on a table to break the cell walls and loosen up the juice inside. The sour juice is needed for the chemical reaction that you are about to start. The fact that the juice is sour should give us some hints about what kind of chemicals make up lemon juice. What do you think the sour flavor might tell us?
• Carefully stick the copper wire about 1 inch into the lemon.
• Make sure your tongue is moist with saliva , or spit. Touch your tongue to the copper wire. Do you notice anything? 
• Stick the paperclip, zinc covered nail or zinc strip into a spot in the lemon about 1/4 inch away from the copper wire. Make sure the wires don’t touch. The wires need to be close to each other because they will be swapping matter in the chemical reaction. If they are too far apart, the matter might lose their way.

• This time, touch your moistened tongue to both wire ends. What do you notice?

When you touched your tongue to just the copper wire, you most likely would not have noticed anything unusual. When you touched your tongue to BOTH of the metal ends, you might have felt a tingle, or noticed a metallic taste. 

The tingle or metal taste you noticed shows that your lemon battery was generating an electric current . That means tiny electrons were moving across the surface of your tongue. Electrons are subatomic particles that zoom around an atom’s center and make up the part of the atom that is negatively charged.

The lemon battery you made is a type of battery called a voltaic battery . These types of batteries are made of two different metals, which act as electrodes , or places where electrons can enter or leave a battery. In your case, the electrical current entered your tongue, which is why you felt a tingle.

So why were we able to stick electrodes into a lemon and get a battery? All voltaic batteries need their metals to be placed in an electrolyte . An electrolyte is a substance that can carry electrical current when dissolved in water. The tiny bit of salt in your saliva makes your saliva an electrolyte, and the sour citric acid does the same thing for lemon juice. Batteries stop working when there is not enough of the electrolyte to react with the metal or not enough metal left to react with the electrolyte.

Going Further

You can generate more electrical current by connecting multiple lemon batteries. Just make a second battery and connect the zinc or steel piece of one battery with the copper wire of the other battery using another piece of copper wire to act as a bridge.

You can use your enlarged lemon battery to power a low-power device like a digital watch or calculator. Remove the regular battery from the digital watch or calculator.  Then, hook up the copper electrode of your lemon battery with battery slot’s positive contact. Connect the zinc or iron electrode with the negative contact. Can you get the device to work?  

If you are looking to test a variable, try making batteries using different fruits and vegetables. Which ones produce the biggest tingle on your tongue? Which ones generate the most electric current?

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37 Cool Science Experiments for Kids to Do at Home

General Education

Are you looking for cool science experiments for kids at home or for class? We've got you covered! We've compiled a list of 37 of the best science experiments for kids that cover areas of science ranging from outer space to dinosaurs to chemical reactions. By doing these easy science experiments, kids will make their own blubber and see how polar bears stay warm, make a rain cloud in a jar to observe how weather changes, create a potato battery that'll really power a lightbulb, and more.

Below are 37 of the best science projects for kids to try. For each one we include a description of the experiment, which area(s) of science it teaches kids about, how difficult it is (easy/medium/hard), how messy it is (low/medium/high), and the materials you need to do the project. Note that experiments labelled "hard" are definitely still doable; they just require more materials or time than most of these other science experiments for kids.

#1: Insect Hotels

• Teaches Kids About: Zoology
• Difficulty Level: Medium
• Messiness Level: Medium

Insect hotels can be as simple (just a few sticks wrapped in a bundle) or as elaborate as you'd like, and they're a great way for kids to get creative making the hotel and then get rewarded by seeing who has moved into the home they built. After creating a hotel with hiding places for bugs, place it outside (near a garden is often a good spot), wait a few days, then check it to see who has occupied the "rooms." You can also use a bug ID book or app to try and identify the visitors.

• Materials Needed
• Shadow box or other box with multiple compartments
• Hot glue gun with glue
• Sticks, bark, small rocks, dried leaves, bits of yarn/wool, etc.

#2: DIY Lava Lamp

• Teaches Kids About: Chemical reactions
• Difficulty Level: Easy

In this quick and fun science experiment, kids will mix water, oil, food coloring, and antacid tablets to create their own (temporary) lava lamp . Oil and water don't mix easily, and the antacid tablets will cause the oil to form little globules that are dyed by the food coloring. Just add the ingredients together and you'll end up with a homemade lava lamp!

• Vegetable oil
• Food coloring
• Antacid tablets

#3: Magnetic Slime

• Teaches Kids About: Magnets
• Messiness Level: High (The slime is black and will slightly dye your fingers when you play with it, but it washes off easily.)

A step up from silly putty and Play-Doh, magnetic slime is fun to play with but also teaches kids about magnets and how they attract and repel each other. Some of the ingredients you aren't likely to have around the house, but they can all be purchased online. After mixing the ingredients together, you can use the neodymium magnet (regular magnets won't be strong enough) to make the magnetic slime move without touching it!

• Liquid starch
• Adhesive glue
• Iron oxide powder
• Neodymium (rare earth) magnet

#4: Baking Soda Volcanoes

• Teaches Kids About: Chemical reactions, earth science
• Difficulty Level: Easy-medium
• Messiness Level: High

Baking soda volcanoes are one of the classic science projects for kids, and they're also one of the most popular. It's hard to top the excitement of a volcano erupting inside your home. This experiment can also be as simple or in-depth as you like. For the eruption, all you need is baking soda and vinegar (dishwashing detergent adds some extra power to the eruption), but you can make the "volcano" as elaborate and lifelike as you wish.

• Baking soda
• Dishwashing detergent
• Large mason jar or soda bottle
• Playdough or aluminum foil to make the "volcano"
• Additional items to place around the volcano (optional)
• Food coloring (optional)

#5: Tornado in a Jar

• Teaches Kids About: Weather
• Messiness Level: Low

This is one of the quick and easy and science experiments for kids to teach them about weather. It only takes about five minutes and a few materials to set up, but once you have it ready you and your kids can create your own miniature tornado whose vortex you can see and the strength of which you can change depending on how quickly you swirl the jar.

• Glitter (optional)

#6: Colored Celery Experiment

• Teaches Kids About: Plants

This celery science experiment is another classic science experiment that parents and teachers like because it's easy to do and gives kids a great visual understanding of how transpiration works and how plants get water and nutrients. Just place celery stalks in cups of colored water, wait at least a day, and you'll see the celery leaves take on the color of the water. This happens because celery stalks (like other plants) contain small capillaries that they use to transport water and nutrients throughout the plant.

• Celery stalks (can also use white flowers or pale-colored cabbage)

#7: Rain Cloud in a Jar

This experiment teaches kids about weather and lets them learn how clouds form by making their own rain cloud . This is definitely a science project that requires adult supervision since it uses boiling water as one of the ingredients, but once you pour the water into a glass jar, the experiment is fast and easy, and you'll be rewarded with a little cloud forming in the jar due to condensation.

• Glass jar with a lid
• Boiling water
• Aerosol hairspray

#8: Edible Rock Candy

• Teaches Kids About: Crystal formation

It takes about a week for the crystals of this rock candy experiment to form, but once they have you'll be able to eat the results! After creating a sugar solution, you'll fill jars with it and dangle strings in them that'll slowly become covered with the crystals. This experiment involves heating and pouring boiling water, so adult supervision is necessary, once that step is complete, even very young kids will be excited to watch crystals slowly form.

• Large saucepan
• Clothespins
• String or small skewers
• Candy flavoring (optional)

#9: Water Xylophone

• Teaches Kids About: Sound waves

With just some basic materials you can create your own musical instrument to teach kids about sound waves. In this water xylophone experiment , you'll fill glass jars with varying levels of water. Once they're all lined up, kids can hit the sides with wooden sticks and see how the itch differs depending on how much water is in the jar (more water=lower pitch, less water=higher pitch). This is because sound waves travel differently depending on how full the jars are with water.

• Wooden sticks/skewers

#10: Blood Model in a Jar

• Teaches Kids About: Human biology

This blood model experiment is a great way to get kids to visual what their blood looks like and how complicated it really is. Each ingredient represents a different component of blood (plasma, platelets, red blood cells, etc.), so you just add a certain amount of each to the jar, swirl it around a bit, and you have a model of what your blood looks like.

• Empty jar or bottle
• Red cinnamon candies
• Marshmallows or dry white lima beans
• White sprinkles

#11: Potato Battery

• Teaches Kids About: Electricity
• Difficulty Level: Hard

Did you know that a simple potato can produce enough energy to keep a light bulb lit for over a month? You can create a simple potato battery to show kids. There are kits that provide all the necessary materials and how to set it up, but if you don't purchase one of these it can be a bit trickier to gather everything you need and assemble it correctly. Once it's set though, you'll have your own farm grown battery!

• Fresh potato
• Galvanized nail
• Copper coin

#12: Homemade Pulley

• Teaches Kids About: Simple machines

This science activity requires some materials you may not already have, but once you've gotten them, the homemade pulley takes only a few minutes to set up, and you can leave the pulley up for your kids to play with all year round. This pulley is best set up outside, but can also be done indoors.

• Clothesline
• 2 clothesline pulleys

#13: Light Refraction

• Teaches Kids About: Light

This light refraction experiment takes only a few minutes to set up and uses basic materials, but it's a great way to show kids how light travels. You'll draw two arrows on a sticky note, stick it to the wall, then fill a clear water bottle with water. As you move the water bottle in front of the arrows, the arrows will appear to change the direction they're pointing. This is because of the refraction that occurs when light passes through materials like water and plastic.

• Sticky note
• Transparent water bottle

#14: Nature Journaling

• Teaches Kids About: Ecology, scientific observation

A nature journal is a great way to encourage kids to be creative and really pay attention to what's going on around them. All you need is a blank journal (you can buy one or make your own) along with something to write with. Then just go outside and encourage your children to write or draw what they notice. This could include descriptions of animals they see, tracings of leaves, a drawing of a beautiful flower, etc. Encourage your kids to ask questions about what they observe (Why do birds need to build nests? Why is this flower so brightly colored?) and explain to them that scientists collect research by doing exactly what they're doing now.

• Blank journal or notebook
• Pens/pencils/crayons/markers
• Tape or glue for adding items to the journal

#15: DIY Solar Oven

• Teaches Kids About: Solar energy

This homemade solar oven definitely requires some adult help to set up, but after it's ready you'll have your own mini oven that uses energy from the sun to make s'mores or melt cheese on pizza. While the food is cooking, you can explain to kids how the oven uses the sun's rays to heat the food.

• Aluminum foil
• Knife or box cutter
• Permanent marker
• Plastic cling wrap
• Black construction paper

#16: Animal Blubber Simulation

• Teaches Kids About: Ecology, zoology

If your kids are curious about how animals like polar bears and seals stay warm in polar climates, you can go beyond just explaining it to them; you can actually have them make some of their own blubber and test it out. After you've filled up a large bowl with ice water and let it sit for a few minutes to get really cold, have your kids dip a bare hand in and see how many seconds they can last before their hand gets too cold. Next, coat one of their fingers in shortening and repeat the experiment. Your child will notice that, with the shortening acting like a protective layer of blubber, they don't feel the cold water nearly as much.

• Bowl of ice water

#17: Static Electricity Butterfly

This experiment is a great way for young kids to learn about static electricity, and it's more fun and visual than just having them rub balloons against their heads. First you'll create a butterfly, using thick paper (such as cardstock) for the body and tissue paper for the wings. Then, blow up the balloon, have the kids rub it against their head for a few seconds, then move the balloon to just above the butterfly's wings. The wings will move towards the balloon due to static electricity, and it'll look like the butterfly is flying.

• Tissue paper
• Thick paper
• Glue stick/glue

#18: Edible Double Helix

• Teaches Kids About: Genetics

If your kids are learning about genetics, you can do this edible double helix craft to show them how DNA is formed, what its different parts are, and what it looks like. The licorice will form the sides or backbone of the DNA and each color of marshmallow will represent one of the four chemical bases. Kids will be able to see that only certain chemical bases pair with each other.

• 2 pieces of licorice
• 12 toothpicks
• Small marshmallows in 4 colors (9 of each color)
• 5 paperclips

#19: Leak-Proof Bag

• Teaches Kids About: Molecules, plastics

This is an easy experiment that'll appeal to kids of a variety of ages. Just take a zip-lock bag, fill it about ⅔ of the way with water, and close the top. Next, poke a few sharp objects (like bamboo skewers or sharp pencils) through one end and out the other. At this point you may want to dangle the bag above your child's head, but no need to worry about spills because the bag won't leak? Why not? It's because the plastic used to make zip-lock bags is made of polymers, or long chains of molecules that'll quickly join back together when they're forced apart.

• Zip-lock bags
• Objects with sharp ends (pencils, bamboo skewers, etc.)

#20: How Do Leaves Breathe?

• Teaches Kids About: Plant science

It takes a few hours to see the results of this leaf experiment , but it couldn't be easier to set up, and kids will love to see a leaf actually "breathing." Just get a large-ish leaf, place it in a bowl (glass works best so you can see everything) filled with water, place a small rock on the leaf to weigh it down, and leave it somewhere sunny. Come back in a few hours and you'll see little bubbles in the water created when the leaf releases the oxygen it created during photosynthesis.

• Large bowl (preferably glass)
• Magnifying glass (optional)

#21: Popsicle Stick Catapults

Kids will love shooting pom poms out of these homemade popsicle stick catapults . After assembling the catapults out of popsicle sticks, rubber bands, and plastic spoons, they're ready to launch pom poms or other lightweight objects. To teach kids about simple machines, you can ask them about how they think the catapults work, what they should do to make the pom poms go a farther/shorter distance, and how the catapult could be made more powerful.

• Popsicle sticks
• Rubber bands
• Plastic spoons
• Paint (optional)

#22: Elephant Toothpaste

You won't want to do this experiment near anything that's difficult to clean (outside may be best), but kids will love seeing this " elephant toothpaste " crazily overflowing the bottle and oozing everywhere. Pour the hydrogen peroxide, food coloring, and dishwashing soap into the bottle, and in the cup mix the yeast packet with some warm water for about 30 seconds. Then, add the yeast mixture to the bottle, stand back, and watch the solution become a massive foamy mixture that pours out of the bottle! The "toothpaste" is formed when the yeast removed the oxygen bubbles from the hydrogen peroxide which created foam. This is an exothermic reaction, and it creates heat as well as foam (you can have kids notice that the bottle became warm as the reaction occurred).

• Clean 16-oz soda bottle
• 6% solution of hydrogen peroxide
• 1 packet of dry yeast
• Dishwashing soap

#23: How Do Penguins Stay Dry?

Penguins, and many other birds, have special oil-producing glands that coat their feathers with a protective layer that causes water to slide right off them, keeping them warm and dry. You can demonstrate this to kids with this penguin craft by having them color a picture of a penguin with crayons, then spraying the picture with water. The wax from the crayons will have created a protective layer like the oil actual birds coat themselves with, and the paper won't absorb the water.

• Penguin image (included in link)
• Spray bottle
• Blue food coloring (optional)

#24: Rock Weathering Experiment

• Teaches Kids About: Geology

This mechanical weathering experiment teaches kids why and how rocks break down or erode. Take two pieces of clay, form them into balls, and wrap them in plastic wrap. Then, leave one out while placing the other in the freezer overnight. The next day, unwrap and compare them. You can repeat freezing the one piece of clay every night for several days to see how much more cracked and weathered it gets than the piece of clay that wasn't frozen. It may even begin to crumble. This weathering also happens to rocks when they are subjected to extreme temperatures, and it's one of the causes of erosion.

• Plastic wrap

#25: Saltwater Density

• Teaches Kids About: Water density

For this saltwater density experiment , you'll fill four clear glasses with water, then add salt to one glass, sugar to one glass, and baking soda to one glass, leaving one glass with just water. Then, float small plastic pieces or grapes in each of the glasses and observe whether they float or not. Saltwater is denser than freshwater, which means some objects may float in saltwater that would sink in freshwater. You can use this experiment to teach kids about the ocean and other bodies of saltwater, such as the Dead Sea, which is so salty people can easily float on top of it.

• Four clear glasses
• Lightweight plastic objects or small grapes

#26: Starburst Rock Cycle

With just a package of Starbursts and a few other materials, you can create models of each of the three rock types: igneous, sedimentary, and metamorphic. Sedimentary "rocks" will be created by pressing thin layers of Starbursts together, metamorphic by heating and pressing Starbursts, and igneous by applying high levels of heat to the Starbursts. Kids will learn how different types of rocks are forms and how the three rock types look different from each other.

• Toaster oven

#27: Inertia Wagon Experiment

• Teaches Kids About: Inertia

This simple experiment teaches kids about inertia (as well as the importance of seatbelts!). Take a small wagon, fill it with a tall stack of books, then have one of your children pull it around then stop abruptly. They won't be able to suddenly stop the wagon without the stack of books falling. You can have the kids predict which direction they think the books will fall and explain that this happens because of inertia, or Newton's first law.

• Stack of books

#28: Dinosaur Tracks

• Teaches Kids About: Paleontology

How are some dinosaur tracks still visible millions of years later? By mixing together several ingredients, you'll get a claylike mixture you can press your hands/feet or dinosaur models into to make dinosaur track imprints . The mixture will harden and the imprints will remain, showing kids how dinosaur (and early human) tracks can stay in rock for such a long period of time.

• Used coffee grounds
• Wooden spoon
• Rolling pin

#29: Sidewalk Constellations

• Teaches Kids About: Astronomy

If you do this sidewalk constellation craft , you'll be able to see the Big Dipper and Orion's Belt in the daylight. On the sidewalk, have kids draw the lines of constellations (using constellation diagrams for guidance) and place stones where the stars are. You can then look at astronomy charts to see where the constellations they drew will be in the sky.

• Sidewalk chalk
• Small stones
• Diagrams of constellations

#30: Lung Model

By building a lung model , you can teach kids about respiration and how their lungs work. After cutting off the bottom of a plastic bottle, you'll stretch a balloon around the opened end and insert another balloon through the mouth of the bottle. You'll then push a straw through the neck of the bottle and secure it with a rubber band and play dough. By blowing into the straw, the balloons will inflate then deflate, similar to how our lungs work.

• Plastic bottle
• Rubber band

#31: Homemade Dinosaur Bones

By mixing just flour, salt, and water, you'll create a basic salt dough that'll harden when baked. You can use this dough to make homemade dinosaur bones and teach kids about paleontology. You can use books or diagrams to learn how different dinosaur bones were shaped, and you can even bury the bones in a sandpit or something similar and then excavate them the way real paleontologists do.

• Images of dinosaur bones

#32: Clay and Toothpick Molecules

There are many variations on homemade molecule science crafts . This one uses clay and toothpicks, although gumdrops or even small pieces of fruit like grapes can be used in place of clay. Roll the clay into balls and use molecule diagrams to attach the clay to toothpicks in the shape of the molecules. Kids can make numerous types of molecules and learn how atoms bond together to form molecules.

• Clay or gumdrops (in four colors)
• Diagrams of molecules

#33: Articulated Hand Model

By creating an articulated hand model , you can teach kids about bones, joints, and how our hands are able to move in many ways and accomplish so many different tasks. After creating a hand out of thin foam, kids will cut straws to represent the different bones in the hand and glue them to the fingers of the hand models. You'll then thread yarn (which represents tendons) through the straws, stabilize the model with a chopstick or other small stick, and end up with a hand model that moves and bends the way actual human hands do.

• Straws (paper work best)
• Twine or yarn

#34: Solar Energy Experiment

• Teaches Kids About: Solar energy, light rays

This solar energy science experiment will teach kids about solar energy and how different colors absorb different amounts of energy. In a sunny spot outside, place six colored pieces of paper next to each other, and place an ice cube in the middle of each paper. Then, observe how quickly each of the ice cubes melt. The ice cube on the black piece of paper will melt fastest since black absorbs the most light (all the light ray colors), while the ice cube on the white paper will melt slowest since white absorbs the least light (it instead reflects light). You can then explain why certain colors look the way they do. (Colors besides black and white absorb all light except for the one ray color they reflect; this is the color they appear to us.)

• 6 squares of differently colored paper/cardstock (must include black paper and white paper)

#35: How to Make Lightning

• Teaches Kids About: Electricity, weather

You don't need a storm to see lightning; you can actually create your own lightning at home . For younger kids this experiment requires adult help and supervision. You'll stick a thumbtack through the bottom of an aluminum tray, then stick the pencil eraser to the pushpin. You'll then rub the piece of wool over the aluminum tray, and then set the tray on the Styrofoam, where it'll create a small spark/tiny bolt of lightning!

• Pencil with eraser
• Aluminum tray or pie tin
• Styrofoam tray

#36: Tie-Dyed Milk

• Teaches Kids About: Surface tension

For this magic milk experiment , partly fill a shallow dish with milk, then add a one drop of each food coloring color to different parts of the milk. The food coloring will mostly stay where you placed it. Next, carefully add one drop of dish soap to the middle of the milk. It'll cause the food coloring to stream through the milk and away from the dish soap. This is because the dish soap breaks up the surface tension of the milk by dissolving the milk's fat molecules.

• Shallow dish
• Milk (high-fat works best)

#37: How Do Stalactites Form?

Have you ever gone into a cave and seen huge stalactites hanging from the top of the cave? Stalactites are formed by dripping water. The water is filled with particles which slowly accumulate and harden over the years, forming stalactites. You can recreate that process with this stalactite experiment . By mixing a baking soda solution, dipping a piece of wool yarn in the jar and running it to another jar, you'll be able to observe baking soda particles forming and hardening along the yarn, similar to how stalactites grow.

• Safety pins
• 2 glass jars

Summary: Cool Science Experiments for Kids

Any one of these simple science experiments for kids can get children learning and excited about science. You can choose a science experiment based on your child's specific interest or what they're currently learning about, or you can do an experiment on an entirely new topic to expand their learning and teach them about a new area of science. From easy science experiments for kids to the more challenging ones, these will all help kids have fun and learn more about science.

What's Next?

Are you also interested in pipe cleaner crafts for kids? We have a guide to some of the best pipe cleaner crafts to try!

Looking for multiple different slime recipes? We tell you how to make slimes without borax and without glue as well as how to craft the ultimate super slime .

Want to learn more about clouds? Learn how to identify every cloud in the sky with our guide to the 10 types of clouds .

Want to know the fastest and easiest ways to convert between Fahrenheit and Celsius? We've got you covered! Check out our guide to the best ways to convert Celsius to Fahrenheit (or vice versa) .

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Christine graduated from Michigan State University with degrees in Environmental Biology and Geography and received her Master's from Duke University. In high school she scored in the 99th percentile on the SAT and was named a National Merit Finalist. She has taught English and biology in several countries.

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Simple Battery Experiment - How to build a simple galvanic battery cell

Posted by Admin / in Energy & Electricity Experiments

An experiment to teach kids about the chemistry of batteries

Materials Needed

• 3 pre-1982 pennies
• Coffee filter
• Copper wire
• Electrical tape
• Multimeter (voltmeter)
• Breadboard (optional)
• Alligator clips (optional)

EXPERIMENT STEPS

Step 1. Using a penny as a template, cut 3 pieces of coffee filter. Make each piece about the size of a penny.

Step 2. Mix two tablespoons of salt with a half of a cup of water. Mix the salt into the water making a saltwater solution with no left over salt.

Step 3. Drop all of the coffee filter pieces into the saltwater solution and allow them to soak.

Step 4. Cut two small pieces of electrical tape about the size of a penny.

Step 5. Strip the ends of two small pieces of copper wire to expose the bare wire.

Step 6. Tape the end of one wire to the top of a nickel, using a small piece of electrical tape. Tape the end of the other wire to the top of a penny, using a small piece of electrical tape.

Step 7: Lay the nickel with the attached wire down on the table with the wire side down. Place a piece of saltwater-saturated coffee filter on the nickel. Place the penny on top with the attached wire.

Step 8: Attach the positive (+) lead of the multimeter to the wire attached to the nickel. Attach the negative (-) lead of the multimeter to the wire attached to the penny. Set the multimeter dial to test for DC voltage. Using aligator clips to connect the wires together makes things easier. Some multimeters have aligator connectors on the testing wires. Read the voltage. How much DC voltage did the single layer galvanic cell produce?

Step 9: Add more voltage to the output by adding more galvanic cells. To make things easy a breadborad was used in the experiment to connect all the wiring. The breadboard is optional, alternatively twist the wires together and wrap the connections with electrical tape. Three single coin cells combined for less than .10 volts in our experiment. How many coin combinations are needed to power a LED?

Science Learned

The simple battery experiment uses the principle of galvanic action. A galvanic cell is created by using two different metals separated by an electrolytic medium. The electrolytic medium is the saltwater saturated into the pieces of coffee filter.

The experiment only produced a nomimal amount of voltage when a single cell was used. There are ways to increase this voltage. One way is by selecting different matals for the experiment. We used copper (penny) and nickel (nickel). Metal elements have different oxidation potentials. On the period chart of elements, lithium (Li) has the highest oxidation potential and gold has the lowest. The greater the difference in each metal's oxidation potential, the more voltage that is released from a galvanic cell. The metal with the higher oxidation potential in a galvanic cell acts as the anode and will corrode. The lower oxidation potential metal is unchanged by the reaction.

In our experiment, nickel has the higher oxidation potential and will corrode. Nickel is a decent metal to use because it has a relatively high oxidation potential and is very cheap. Increasing copper with a different metal with a lower oxidation potential would result in more voltage. Unfortunately, the best materials such as silver, titanium, and gold are very expensive.

The second way of producing more electricity with this type of battery is having more surface area. Since we are using coins in the experiment the only way to get more surface area is by using multiple coins. We used additional nickel and copper (penny) coin combinations in parallel to increase the voltage output. More coins or larger pieces of metal will result in higher voltage outputs from the galvanic battery.

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Lemon Battery Experiment

This post may contain affiliate links.

Have you ever tried the lemon battery experiment? Well if not, it’s time to give it a try!  Here I will show you how a lemon can light up a light bulb or even a small clock!

Lemon batteries are an experiment that has been around for a while, but it is always such a delight to see it in action! Kids just love it. I’ll show you how to build your own lemon battery today. This is an awesome science project for kids, or great for any STEM project!

Science has always been more of a boy field, but more and more girls are becoming increasingly interested in science. Did you know that only 1 in 1,000 girls pursue a STEM career? Hopefully we can soon change that! This is a fun way to start them on the path and get young girls interested.

My daughter loves learning about all kinds of science fields from nature to electricity to coding, but I would say leans more toward artistic careers for the future. However, I love doing science experiments with her to help her see how great science can be. This lemon battery is a great one to start with if you have kids expressing an interest in STEM projects.

STEM, if you are not familiar stands for Science, Technology, Engineering, and Math. We received a free STEM themed box from Green Works teaching us how to create this project, but it is easy to recreate on your own!

Supplies to Make a Lemon Battery:

Small LED Light Bulb  (LED= light-emitting diode) 4 Lemons Alligator Clips Zinc nails, a zinc strip or a galvanized nail (can be easily found at a hardware store) Copper Wire, a copper strip, or copper coin- pennies work great

Try also this fruit powered digital clock !

How to Make a Lemon Battery:

The first step is to roll the lemons on a hard surface to break apart the juice pockets in the lemon cells. Get ready to make some lemon power!

In each of the 4 lemons, make 2 small slits with a knife and place a nail in one side and piece of copper wire or a copper penny on the other side.

Connect the nail on the first lemon to the copper wire or copper pennies on the second lemon. Continue this and connect them all in a circle except for the first and last ones.

On these two last lemons, connect one alligator clip to a nail and to part of the LED bulb and the other to a copper wire and to the other part of the light. This will complete the electrical current and light up the light!!  Be sure to match up the positive electrode and the negative electrode correctly. If you don’t the battery will not work properly.

Connect a multimeter to test the voltage. Will the volts be higher if you make the chain longer and add more lemons?

How Does the Lemon Battery Work?

A battery generates electricity by passing electrons between two. different metals (one that is positively charged and one that is negatively charged). These electrons create an electrical current as they pass through a solution with molecules that will move the charged particles back and forth between the two different metals. In this instance, the solution is the lemon juice.  

The lemon battery is made with two different metals: copper wire (you could also do it with a penny) and a galvanized (or zinc coated) nail. The lemon has citric acid in the juice. The zinc and copper are the electrodes and the lemon juice is the electrolyte. A chemical reaction happens that is called oxidation-reduction, where there is a transfer of electrons. The zinc is oxidized inside the lemon, some of its electrons are transferred to the copper to reach a lower energy state. The energy released creates the power, lighting up the bulb. The wires allow this transfer of energy.

Try a different kind of fruit battery~ Do other citrus fruits work, too?  Will limes, grapefruit or oranges work just as well?

Did you enjoy this lemon science project?  Try some of my other fun science experiments and activities!

Check out some more of our cool STEM  activities & Science Fair Projects .

See More Electricity Experiments:

Science Art: Conductive Paint Circuits Christmas STEM: Gingerbread House Paper Circuits EASY Play Dough Circuits Building Electric Circuits: STEM Challenge Cards Origami Firefly Paper Circuits

Former school teacher turned homeschool mom of 4 kids. Loves creating awesome hands-on creative learning ideas to make learning engaging and memorable for all kids!

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Very awesome! I think my 8 year old would enjoy making a battery out of lemons!

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Issue 79 out now.

Issue 79 available now, in interactive & digital..

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Kids' Basics: The Battery Experiment

Teaching kids about batteries.

Daniel Koch

Issue 34, May 2020

This article includes additional downloadable resources. Please log in to access.

An open-ended and adaptable experiment to keep you thinking while at home.

BUILD TIME: AN AFTERNOON DIFFICULTY RATING: BEGINNER

This month, we’re going for a different approach for Kids’ Basics. With isolation our current reality thanks to COVID-19, we’re not going with our regular-type step-by-step build a basic circuit explanation. This is fine most of the time, but it’s an ‘over-and-done-with’ project, with little room to expand your thinking once the project is complete. In education circles, we call this a ‘closed’ task.

This month, we’re presenting an ‘open’ task investigative experiment and a tool with which to conduct it. We’re going to show you how to build your own batteries, and then step you through running an experiment to see which one performs the best. It will be variable and adaptable, with no one right answer and no one fixed project. That means you can make it simple or complex, and go for an hour or a month. While we start with a fair bit of theory, younger makers can skip to the experiment and run it with just a little help from an adult. The result is more like our ‘Classroom’ column, but with more experiments and aimed at kids.

Batteries underpin modern life as we know it. From the basics such as torches to our Information and Communication Technology (ICT) devices, to household alarms, emergency lighting, clocks and remote controls, they’re in nearly every direction we look. They also come in a variety of forms. You may have seen someone loading tiny batteries into their hearing aids, while goods are delivered to your local supermarket in a truck which has a much bigger starter battery than the ones you may see under the bonnet of the family car.

WHAT IS A CELL AND BATTERY?

A battery is a collection of individual cells. A cell is an arrangement of chemicals that take part in a chemical reaction, which produces an electric current. The basic components are two electrodes of different material, and an electrolyte that helps make the reaction happen. More on this in a moment. All materials on earth (and indeed, in the universe) are chemicals in one form or another. The word ‘chemical’ in social use often implies something manufactured and often toxic, but in science, the word means any pure or compound substance.

A PRIMARY-SCHOOL CHEMISTRY SUMMARY

For our purposes, atoms are the smallest independent particle of matter (stuff) in our universe. They are made up of Protons, Neutrons, and Electrons. The atom is the smallest independent particle because protons, neutrons, and electrons generally don’t exist on their own, only within an atom. There are smaller particles and times where protons, neutrons, and electrons exist by themselves, but that isn’t taught until senior high school and doesn’t affect our battery lesson at all.

Most atoms have a ‘nucleus’ of protons and neutrons, surrounded by layers of electrons. The exception is Hydrogen, which has no neutron. Protons have a positive electrical charge, while electrons are negatively charged. Neutrons have no charge, hence the name coming from the word ‘neutral’. A proton and an electron balance each other, but don’t touch. Instead, the electrons fly around in layers a lot like satellites orbit earth. Starting from hydrogen, each atom has more protons and neutrons in its nucleus than the one before, and therefore more electrons. The layers of electrons in the ‘shell’ have a fixed number; the first shell can hold two electrons, the second can hold eight, the third eighteen and the fourth can hold thirty two.

The thing is, the layers are not always full. Each atom contains, generally, the same number of electrons as it has protons. Oxygen, for example, has eight protons, and eight electrons. The first shell has its two electrons, while the second shell is left with six. However, electron shells like to be full. Atoms may give away electrons, or take them, depending on how many they need to reach a state where their shells are complete. Exactly how this works is a chemistry lesson (or several) on its own, but for now, you just need to know that unless an atom’s electron shells are full, it can react chemically with other elements. Also note that the shells do not always fill as described above, and sometimes a shell will start filling before the shell below it is full. The outer shell is the one that reacts, or takes or gives electrons.

Any substance you encounter in the world can be grouped into three main categories: Elements, which are pure substances all of the same atoms; compounds, in which different atoms are stuck to each other in different ways to form molecules; and mixtures, where different elements or compounds are mixed together but not chemically bound together. All pure elements are shown on a table called the Periodic Table of the Elements. It shows the atomic number, which is the number of protons in the nucleus, as well as other information that doesn’t concern us now. Some versions display the number of electrons in each shell, which is useful to us.

The last thing you need to know is about ions. There are situations where an atom has more or less electrons than protons. It, therefore, has an electrical charge and is called an ion. Ions want to satisfy the balance between protons and electrons, so they will react with other elements or compounds to achieve this. They can also be carried by ‘electrolytes’, chemicals which can weakly bond with an ion and allow it to move. They are usually liquids but liquids in a chemistry sense may still be very thick and not runny at all.

That chemistry lesson is very compressed, and probably wouldn’t even stand up to a high school class, however, it does the job for now.

That brings us to the battery. Some chemical elements and compounds will react together, and when they do, electrons move to satisfy the shells of different atoms. Some substances need electrons, others want to give them away. Some reactions can produce an excess of electrons while others produce a deficit, or too few electrons. Some types of chemical bonds are stronger than others. Some chemicals will strip an atom from the rest of the mass as an ion, leaving behind an excess or deficit of electrons. The right combination of these things forms an electrochemical cell. A battery is two or more cells connected together. An excess of electrons builds up on one electrode as the ions carry across the electrolyte, while there is a lack of them on the other electrode. If the electrodes are connected by a conductor, electrical current flows.

A BRIEF BUT USEFUL HISTORY LESSON

Batteries aren’t a new invention, although some of the chemical combinations used to make them are very recent technology. A quick look at their history may help shape your experiments moving forward.

The generally recognised first battery invented was a creation of Alessandro Volta. He built on observations of another Italian scientist, Luigi Galvani, who noticed muscle movements when dissecting animals with metal implements. Volta’s device was a series of metal plates separated by cloth or cardboard soaked in saltwater. Saltwater is an effective electrolyte. This creation was called a ‘pile’, and Volta thought the electrical current came from the metals touching each other. We now know that’s not accurate, but the experiment produced electricity nonetheless.

Volta’s pile had a few issues, the main one being the weight of the metal plates. He had used zinc and copper in his final design, and the pressure squeezed out the electrolyte from the cloth. Scotsman William Cruickshank laid Volta’s pile on its side in a box, which solved this problem. The other main problem with Volta’s battery was that it produced hydrogen gas around the copper electrode, which reduced the surface area of the copper exposed to the electrolyte. Despite this, our experiment will be based on the Voltaic pile, albeit in Cruickshank’s horizontal arrangement, because it is the most easily constructed.

The next major development of relevance for us was from John Frederic Daniell, an English chemistry professor. He got around the hydrogen issue by using two different electrolytes, separated by a porous membrane. He used a copper pot as both container and electrode, with copper sulphate solution in it. Sitting in this was a clay container with sulphuric acid in it, with a zinc electrode in the middle. The clay barrier allows transfer of ions but keeps the solutions generally separate. Others improved this system over time.

Unfortunately, that’s where our history lesson ends, because from here on out, materials used go beyond household availability. Even the ‘heavy duty’ type household batteries, which are often called ‘carbon-zinc’ batteries, actually use manganese dioxide and an electrolyte of ammonium chloride.

BATTERY BASICS

With the chemistry behind batteries covered, let’s recap the physical essentials. We need two electrodes of different materials, so that each has a different number of electrons in its outer shell. We also need an electrolyte, a chemical to carry the ions between the electrodes. If we’re making the Daniell cell, we’ll need two electrolytes and a porous barrier between them.

In any electrochemical cell, one electrode becomes positively charged, and the other negatively charged. Because electrons have a negative charge, it’s the electrode with an excess of electrons which becomes the negative electrode, called the anode. The positively charged electrode is called the cathode. The challenge here is that electrons flow from the negative electrode, to the positive electrode, where there are less electrons. This is counter-intuitive but happens because the electrons are negatively charged. The terminology does not reflect where there are more or less, like positive or negative would in maths.

For this to happen, we need materials with different numbers of electrons in their outer shells. For our experiment, you could use the periodic table to choose materials, or you could just try some if you don’t have confidence reading the periodic table. We’ll need an electrolyte, too. We’ve already given enough theory, so we’ll just say for now that most electrolytes used in basic electrochemical cells are acids. We don’t mean highly corrosive car battery acid, either. Acids around the house can be things like vinegar, lemon or orange juice, the starches in potatoes, or even grape juice. And that leads us to our first experiment.

Before we do, we’ll introduce two tools you’ll need for this experiment. All electrochemical cells and batteries show a higher ‘potential difference’ when unloaded. Potential difference is the name for the difference in charge between one electrode and the other, and is measured in ‘volts’, hence the somewhat incorrect but convenient term ‘voltage’.

To make the measurement more realistic, we need a load, and the easiest way to do that is with a resistor. This way, we don’t have to worry that a voltage may be too high or low for a given component like an LED or light globe. We suggest a 100Ω (100 Ohm) resistor for this.

The second tool after a consistent load is a multimeter. This tool is available from major electronic retailers, starting from around $10. It measures a variety of characteristics, but we are interested in its ability to measure voltage and current. It will also tell us the ‘polarity’ of the current, which is the way it is flowing.

LET'S EXPERIMENT!

These parts are the electronic parts required for all of the experiments following. However, you'll need to check each experiment for the additional parts required to complete them!

* Quantity shown, may be sold in packs. You’ll also need a breadboard and prototyping hardware.

Experiment 1:

Lemon battery.

The first experiment involves making a battery from lemons. Yes, lemons! Lemon juice is acidic, filled with acetic (or citric) acid, with a few other acidic compounds thrown in. It happens to make a viable electrolyte. We need two dissimilar (not the same) metals as well. For this, we need copper and zinc.

SOURCING MATERIALS

Copper and zinc aren’t as hard to find as you might think. Zinc is used to ‘galvanise’ other metals to protect them from chemical reactions from weathering, which otherwise corrode them. This means most galvanised metals are zinc coated and suitable for use. Nails are a great place to start but as you’ll see, surface area matters in this experiment. You may be able to use lots of nails side by side or use galvanised washers instead. Look for ‘hot dipped’ rather than ‘electroplated’ galvanising, as it’s much thicker. You may also consider coach screws or bolts instead of nails.

Copper isn’t quite as easy to find. Copper nails were once common but now rare, and because they’re often used only decoratively, they’re usually thinly electroplated, too thin for our use. The main option is copper water pipe. You can buy this in one metre lengths from chain hardware stores, and have an adult cut small sections off. If this is not something your adults can do, most hardware stores and plumbing suppliers sell copper joiners as well. These and the pipe sections can be used as-is or hammered flat. Other sources could be copper-coated welding rod, earth rod, or tubes from hobby shops.

Arrange your materials: The lemon, electrodes, resistor load, jumper wires and multimeter. Also, print the ‘Experiment 1 Recording Sheet’ or draw one up yourself.

Carefully push the electrodes into the lemon, roughly in the position shown. Measure the distance between them and write it in the ‘separation distance’ field.

Connect the jumper wires to the electrodes. Be careful they don’t touch. Nothing dangerous will happen, but your battery will go flat very quickly.

Plug the leads into your multimeter, and set the dial to measure voltage. On most multimeters available today at retailers, the setting will have the symbol shown. If you have a manual range meter, set it to 2V.

Measure the voltage between the two electrodes. Put the red lead on the zinc electrode, the anode, and the black on the copper electrode, the cathode. Write the voltage down on the recording sheet under ‘Open-circuit Voltage’. Check to see if the polarity symbol appears in the multimeter display.

Connect the resistor between the jumper leads and check the voltage across the electrodes with the multimeter. Write the voltage in the ‘Loaded Voltage’ field on the recording sheet. Is it different? There is a column on the recording sheet for ‘Observations’ where you can write down things you notice.

Disconnect the resistor from the anode (zinc) side of the jumper lead. Connect the black lead to the jumper wire, and set the multimeter to measure current on the smallest setting. The photo shows how this looks on most multimeters.

Touch the red probe of the multimeter to the free end of the resistor. You should see a reading on the display. Write it down in the ‘Loaded Current’ section of the recording sheet.

Take the red probe off the free end of the resistor and place it on the jumper lead, bypassing the resistor. Write the current value down in the ‘Short-Circuit Current’ field.

Take the electrodes out of the lemon, clean them with a damp rag or paper towel, and insert them again, a little closer together.

Repeat the above set of measurements with the new electrode positions, recording each where relevant. Your sheet should end up with several lines full, depending on how far you move the electrodes each time.

With a fresh lemon and new set of electrodes, repeat the entire above experiment, but this time, roll the lemon on a table with a bit of downward pressure, so that the internal membranes of the lemon are broken.

ANALYSING YOUR RESULTS

Look at your results on the recording sheet. Are there trends you notice? How do the observations and measurements change when the electrodes are moved further apart or closer together? Were the numbers any different when you used the lemon with the mooshed membranes? How do the measurements and observations compare to what you thought might happen after reading the theory above?

Experiment 2:

Mixing it up.

Now that you’ve completed this scaffolded task, which was closer to a closed task, we’re heading into something more open. We suggested zinc and copper because they are known to work well. However, they are not the only metals which can be used to make an electrochemical cell. Now we’re going to investigate other metals. This is where things get a little more open-ended. Your task is to gather as many metal samples from around your house as you can. Ask adult permission of course, then gather anything from steel nails to fishing sinkers. Then, using a lemon, try each combination and record the results. We’re going to use the open circuit voltage and loaded voltage for this test.

Before you start, list all the variables you can think of on the recording sheet. In a fair test or experiment, we only change one variable and keep all others the same. The variable we are changing is the combination of metals. What are some things that need to stay the same? See the Analysis section if you get stuck.

Print or write your own ‘Experiment 2 Recording Sheet’. Gather your materials and arrange them on a table.

Combining Materials

The number of combinations is not simply double the number of metals. Have a look at the example list here. Do you notice any patterns? The mathematically-minded readers might even like to try to find an algebraic formular to describe this. For everyone else, Write your first material once for every other material. We started with copper. Then, your next material will have one fewer options, because it was already paired with your first option above. Your next material will have one fewer options again, and so on.

Write different combinations of metals in the ‘Combinations’ column. You can try different combinations with one common metal. See the ‘Combining Materials’ box for details.

Make a hypothesis (a prediction based on what you already know and have observed so far) about which metals will work together, and record it at the top of the sheet.

Measure the open-circuit (unconnected besides the meter) voltage of each combination with the multimeter set to Voltage. Take note of the polarity symbol to determine which metal is the anode and which is the cathode, and record this as well as the open circuit voltage. Because the meter is set up for 'conventional current flow', the polarity is opposite what we might think. In a circuit, current flows from positive to negative. Once electrons were discovered and understood, it was realised that electrons flow the other way. That's why the anode electrode is where the electrons flow from and the cathode where they flow to, yet the negative side of a component is the cathode and the positive side the anode.

Connect two jumper leads, with the 100Ω resistor in the middle, to the electrodes and measure the loaded voltage. Record this as well.

Take out one or both electrodes, clean them with a rag or paper towel, then try a different combination. Check the lemon at each stage and use another if the holes are becoming too dirty for good contact with the metals.

ANALYSING THE RESULTS

Starting with the variables, hopefully you had the distance between the electrodes, and the surface area of the electrodes as things to keep the same between tests. These could strongly influence your results. There are other things too, like whether the acidity of the lemon was the same if you had to change. Revisit your variables list and see if you would add or change anything now.

Looking at the data you have gathered, which set of electrodes gave the highest voltage? Were there any surprises in the differences between open-circuit and loaded voltages? Were there any combinations which had a much bigger or smaller drop between open-circuit and loaded voltages?

Experiment 3:

Electrolytes.

After experimenting with different metals, we’re going to now have a go at using different electrolytes. As noted, a fair test needs to be kept consistent, with all variables kept the same except for one that is carefully changed. There are actually three types of variables. The Independent Variable is the one that we are changing. In this case, that is the electrolyte. The Controlled Variables are the ones that are going to be kept the same. We’ll ask you to think about those in a moment. The Dependent Variables are the ones which change because of changes we make. In other words, the variables we observe, measure, and record. In this test, the dependent variables will be the voltages measured, both open-circuit and loaded.

The sources of electrolytes can be varied. Many fruits and some vegetables work, as will some household liquids. Saltwater is one suggestion, as is vinegar. We’re not suggesting both of these will work, we’re just showing you which directions you might head in. With both food and household chemicals, ask your adult first. Some chemicals are dangerous and even if they’re considered safe, if there is a label on the package, read the details or have your adult read them aloud.

If you’re using liquids, they will need to go into a container. Think about controlled variables and how this will compare to the food items you might be using. How are you going to keep all variables the same?

The point of this experiment is to explore and observe. Some of the products described or shown will not work. we don't want to give all the answers away, we want you to find your own answers by investigation.

With that in mind, have a good look around your house for anything that might work, but: READ LABELS FOR SAFETY INFORMATION! and ask an adult about anything you don't already use, like fruit juice. Be curious, but be safe.

Print or draw your own recording sheet, and gather your materials. You will need to choose two electrodes, based on your previous experiments.

Fill in the sections of the recording sheet for your hypothesis, controlled variables, and the list of electrolytes you’ll try. The electrode materials are two of the controlled variables, but we have a place for those separately.

Insert your electrodes into an electrolyte to be tested. This might be something solid like a fruit or vegetable, or a liquid in a container.

Measure the open-circuit voltage with the multimeter, and record it on the sheet. Remember to set your multimeter to the voltage setting.

Measure the loaded voltage using two jumper leads and the 100Ω resistor.

Remove the electrodes and clean them with a rag or paper towel. If you had liquid in a container, clean the container too.

Analysing experimental results should be becoming familiar to you now. Start by looking for trends or patterns in the recorded data, and use it to see if your hypothesis was correct. Which electrolyte turned out to be the best performing? How else could we test this?

Further Experiments:

Now we’re going to step up the challenge. So far, we’ve presented one structured experiment, and two scaffolded but open tasks. Now, we’re turning you loose. As mentioned earlier, different chemical combinations perform differently to each other. You have tested different metal combinations in lemons, and different electrolytes with the same electrodes. What if we present you with a new idea? It is possible that even though one set of metals performed the best in lemons, those metals may not be the best for other electrolytes. There is a big combination now of different metals to test with different electrolytes. Testing this is your challenge.

Some questions to get you started are: How are you going to test this? What is your exact hypothesis or aim going to be? How are you going to record your observations? Which variables will you keep controlled and which will you vary? What materials and supplies do you need, if you haven’t got everything already?

Challenge 1:

Now that you’re familiar with home-made electrochemical cells, it’s time to back-track. Earlier, we tested which electrochemical cell in each experiment performed best based on open-circuit and loaded voltages measured at the start. However, here’s a hypothesis for you to test: ‘Different chemical combinations in an electrochemical cell will produce different voltages for different times’. This is a hypothesis only. We aren’t stating this as fact yet, though it does give you a test to run. Maybe the highest voltage cell you made is not the best because it goes flat fast, and a lower voltage combination of electrodes and electrolyte may produce the lower voltage for much longer. If that is the case, which is the ‘better’ cell, and why?

The answer really depends on how you justify it, and what criteria you value over others. If you’re stumped for ideas, see the Hints section at the end of the article. This test will keep you going for a while, we expect. You might run several combinations side by side and test one after another at the same interval, or complete one test then start another. It will really depend on how many jumper leads and resistors you have!

Challenge 2:

You will probably have noticed by now that the voltages and currents out of these cells are very small. One thing that we haven’t done since the first experiment is to test the current of the cells, but none of them are very high. How do you make them more useful? Connect them in series to increase the voltage, and parallel to increase the current! Choose one of the cell designs described previously. It may be the original lemon cell, one of your other metal combinations or a different electrolyte, and make sure you can make quite a few of them. Next, you’ll need to measure the voltage and current of each. Measure this as the loaded voltage and current. Then, you’ll need to choose a load to drive. As we discovered in DIYODE Issue 004, you certainly won’t be charging your mobile phone, but you may easily light a small light bulb or an LED. From the data from the supply, write down the current and voltage needed to drive your chosen load. An LED normally needs a resistor to survive its full rated life hours, because they do not current limit themselves, even with the voltage matched. However, for such low-power sources such as these, you can leave the resistor out.

Connect your load to one cell. Measure the voltage across it and current going through it. This is unlikely to light the LED and almost certainly won’t light the globe if you’re using one. This will tell you how the load has affected the performance of the cell. Record your measurements. At this point, how many cells do you think you will need to fully supply our load? Remember that LEDs are polarised, they have a negative and positive side. With such a small power source, you can try both ways if you’re unsure.Now, make a second cell, and connect it in series with the first. Your load now connects across the outer electrodes. You’ve made your first battery! Measure voltage and current again, and record them. Keep adding cells, measuring, and recording, until you reach the right voltage for your load. How many cells have you had to connect in series?

Make more cells so that you have a second set of cells connected in series the same as the first. Connect it in parallel with the first. Measure the current and voltage again. Is it enough to drive the load yet? An LED will start showing light well before its rated current, and so will a light globe. They just won’t reach full brightness until the specifications are met.

If the battery is still not producing the full current of the load, add another series-connected set in parallel to the first two, and so on until the load is fully supplied. How does this compare with your predictions at the start?

EXPERIMENT 1: In step 6, the loaded voltage should be lower than the open-circuit voltage.

EXPERIMENT 2: Because the multimeter works in conventional current flow, the electrons moving from anode to cathode are opposite to the convention. So, if the black lead is on the anode and the red lead on the cathode, the display will show correct polarity. If the red lead is on the anode and the black on the cathode, the ‘-’ sign will show on the display next to the voltage.

EXPERIMENT 3: Don’t forget to try the internet favourite, the potato! Fruit juices and many other drinks work well too. Does milk work? Try powders from the pantry like tartaric acid, sugar, salt or bicarbonate soda, mixed with water. Coca-Cola is high in phosphoric acid, and you doctor would probably argue that this is the best use for it.

CHALLENGE 1: Which is the better cell really depends on what you expect it to do. Some batteries need to provide a lot of current fast, for a short amount of time, like your family car battery. Others, like smoke detector batteries, need to produce a little current for a long time. If the higher voltage goes flat before it’s done its job, it isn’t the best. On the other hand, if the battery that lasts the longest never gives the current or voltage required, even in series and parallel as you’ll explore later, then it’s no good either. Size may be a factor too. Test each battery’s output against time. Leave the 100Ω load connected and measure the voltage. Will you test every minute, every ten minutes, every hour, or a different time?

Challenge 3:

In the theory section, we described the Daniell cell, a type of electrochemical battery. This is similar to a Galvanic Cell pictured here. The Galvanic cell is two half-cells of an electrolyte and electrode each. The half-cells are connected by a salt bridge, which allows ions to be transferred. The salt bridge in labs is often a glass tube filled with salt solutions, but in kids’ chemistry sets, is often just filter paper soaked in saltwater. You might come up with a different way to make yours.

Can you make a Daniell or Galvanic cell? Will you use a salt bridge or some porous container? You might be adventurous enough to make a thin-walled container out of air-drying clay. You might try an aluminium drink can as an outer container-electrode, but be careful to have an adult cut the top off and cover the sharp edges with tape. Other metal containers work too, or you could use a plastic or glass outer container with a metal electrode (or electrodes connected together) in it.

Where would you source electrolytes for that? The electrolytes used are generally salts of the metals involved. If you use a copper electrode and a zinc electrode, you would most probably be using copper sulphate and zinc sulphate as they dissolve in water as the two electrolytes. Where does someone get chemicals like that? They’re a bit more common than you might think. Zinc sulphate is used as a powder for people with zinc deficiency (too little zinc in their bloodstream), while copper sulphate crystals are used as a pool chemical. Both are used as a fertiliser and nutrient correction additive for plants, and both are available in the garden section of most hardware stores. If you choose other metals and look for other metal salts (sulphates and nitrates), look for similar sources.

Whatever you use, discuss everything with your adult, read all safety precautions on the labels to make sure it’s suitable, and keep the original containers with your experiment. Also record what you do at every step of the way so that at all times, every chemical used in every part of the experiment is documented. Write your planned procedure out first before you start and keep the record with your experiment. We’re not even going to provide a Bill of Materials for parts list, because there are far too many possibilities.

Using a MULTIMETER

Many Kids’ Basics readers will be using a multimeter for the first time, while others will find a few quirks while running these experiments. The first concerns polarity, which means which side is negative and which is positive. Normally, you connect the red probe to the positive side of anything, and the black probe to the negative. The polarity of the measured voltage is indicated on the screen, usually by the presence of a ‘-’ sign if the probes are reverse-polarised. This happens if the red probe is connected to the negative of the source voltage, and the black to the positive.

However, this is based on ‘conventional current flow’ from positive to negative. As we discuss in the article, electrons actually flow from the negative to the positive, because the terms ‘negative’ and ‘positive’ were decided before electrons were discovered and understood. Before that, researchers working with electricity had theories about what they were seeing, but nobody knew. When electrons were discovered, it was found that electrons are particles that have a negative charge. The electrons move from the anode to the cathode. However, the anode of a component is its positive side where we think of current as flowing in, and the cathode is the negative side where current flows out. Have a close look at the diagram to follow along. The arrows are colour coded to help.

OTHER POINTS TO NOTE

Finally, measuring current works differently on different meters. Traditionally, all multimeters had a ‘COM’ socket, for ‘common’, where the black lead goes. There were two red sockets, one for current measuring, usually marked ‘A’, for ‘Amperes’; and another for everything else, like voltage and resistance. To measure current, you plugged the red lead into the ‘A’ socket and turned the dial to the current setting.

The meters are still made the same way, but many modern meters actually measure currents below a certain value through the ‘everything else’ socket. This is commonly anything below 500mA, but that limit varies in some meters. You still turn the dial to the current setting, usually labelled ‘DC A’ or ‘A DC’. Have a close look at the labelling at the sockets to find out.