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BEARDED SCIENCE GUY

• Aug 13, 2023

Walking Water Experiment: A Fun and Colorful Rainbow Science Activity

Updated: Aug 15, 2023

Hey there, science enthusiasts! If you're searching for a fun, simple, and visually striking experiment to do with kids aged 5-10, the walking water experiment is a fabulous choice. Not only does it demonstrate capillary action, but it's also an excellent way to ignite a child's curiosity and set the stage for further scientific exploration. Let's dive in!

Materials Needed for Your Walking Water Experiment:

Clear plastic or glass cups (5 - 7)

Paper towels (preferably the absorbent kind)

Food coloring (primary colors: red, yellow, and blue)

Step-by-Step Guide for the Walking Water Experiment

Water usually flows downward, but did you know it can also "walk" sideways between cups? The Walking Water Science Experiment is a great way to see this in action. It's easy to set up and doesn't take much time. Let's get started and discover the science behind walking water!

Set Up the Experiment:

Place 6 cups in a circle or in a straight line.

Fill every other cup about two-thirds full of water.

In the first cup, add a few drops of red food coloring, in the third cup, add blue, and in the fifth cup, add yellow.

Preparation of Wicks:

Fold a paper towel lengthwise several times to create a wick. It should be about an inch in width.

Make enough wicks for each gap between cups and extras to connect the end cups if you're setting them up in a line.

Walking Water:

Place one end of a paper towel wick in a cup with water and the other end in an empty cup next to it.

Do this for all the gaps. You should see the paper towels start to absorb the colored water.

Observation:

Over the next several hours, watch as the colored water "walks" up the paper towel and down into the empty cup.

Eventually, the water in the two adjacent cups will level out and mix. Red and yellow will produce orange, yellow and blue will become green, and blue and red will turn purple.

Discussion:

Ask the kids or students why they think the water moved against gravity.

Discuss the concept of capillary action: the phenomenon where liquid flows in narrow spaces without external forces like gravity.

Further Investigations with the Walking Water Experiment:

Different Materials: Replace paper towels with other materials like cotton strings, cloth strips, or even toilet paper. How does the rate of water absorption change?

Adjust Liquid Volume: Start with different amounts of water in the initial cups. Does a fuller cup make the water walk faster?

Temperature Effects: Use warm water in one set of cups and cold water in another. Observe any differences in the rate of absorption or color blending.

Different Colors: Use other food coloring shades or even try making secondary colors initially to see what new colors you can create in the empty cups.

Different Vessels: Experiment with taller glasses or wider containers. Does the height or width of the container make a difference?

Paper Towel Length: Try longer or shorter paper towel strips. How does the length affect the speed and amount of water transfer?

Exploring Porosity: Get different brands of paper towels and discuss the idea of porosity. Which brand works best? Why might that be?

The walking water experiment isn't just visually delightful; it's a hands-on way to teach children about basic scientific concepts. It's also flexible enough to allow for plenty of additional investigations and inquiries. The real joy is in seeing kids' eyes light up as they engage with the process, ask questions, and explore further on their own! So, put on your lab coats, little scientists, and let the wonders of science sweep you away. 🌈🔍🧪

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Rainbow Walking Water Science Experiment for Kids

This walking water science experiment is so much fun and super easy to do! My kids absolutely loved it! It even comes with free printable recording sheets for kids as young as preschool! Check out the video to see how easy this walking water experiment really is. This rainbow activity is perfect for spring science!

Walking Water Science Experiment

Ok, this might just be our favorite science experiment! The whole family (adults included) were completely mesmerized with process. We all couldn’t believe how quickly the water traveled up the paper towel and neat it was to watch the colors mix together.

We have wanted to try it out for a long time now and I am kicking myself for waiting so long. I don’t know why, but I thought it might be difficult to do or take a long time. I was way wrong. It was very easy and we started seeing results right away!

Related: Simple Spring Science and STEAM Activities

The walking water science experiment is great at any time of the year, but it is especially perfect for spring. I love doing rainbow activities in the spring, so this was a great addition to our rainbow theme activities.

If you are looking for simple science to do with the kids and something that will really WOW them, this is definitely one to try.

You only need a few simple supplies that you probably already have around the house.

Setting Up the Rainbow Science Experiment

Supplies Needed:

• Printable walking water recording sheets (button to download at the bottom of the post)
• Small plastic cups or glasses
• Paper towels (*read my tips below for picking the right ones)
• Food coloring in primary colors

* The pick-a-size paper towels are best because then you just use half sheets for each cup. If you only have full sheets, then cut them in half. I’ve also heard that more absorbent paper towels work better too. I buy the cheap store brand ones, and our water moved pretty quickly from cup to cup, so I am not sure how important that is. It may have went quicker with something more absorbent though.

1. Print out the recording sheets and make copies, if needed.

2. Place 7 cups in a row and pour water in the 1st, 3rd, 5th, and 7th cup. My cups were about 3/4 full. I have since heard that fuller is better.

3. Add 5 drops of red food coloring to the 1st cup and the 7th cup.

4. Add 5 drops of yellow food coloring to the 3rd cup.

5. Add 5 drops of blue food coloring to the 5th cup.

Doing the Walking Water Experiment

You want to try to use the same amount of food coloring in each cup. When I did this with my kids they did drop an extra one or two in since they can’t control it well, but I just added a drop or two more to the others to even it out.

6. Take a half sheet of paper towel and fold it in half lengthwise and in half again lengthwise.

7. Trim off some of the length so that there isn’t too much excess paper towel that will stick up in the air between each cup. This will make the water walk more quickly.

8. Place one half of a rolled paper towel in the 1st cup and place the other half in the cup next to it. Then another paper towel from 2nd cup and into the 3rd cup. This continues until you have placed the last paper towel that drapes over from the 6th cup to the 7th cup.

9. Stare at the cups and watch what starts happening. You should quickly be able to see the colored water begin to crawl up the paper towel.

10. Don’t forget to do the first part of the recording sheet. Students will predict what they think will happen.

This walking water experiment is AWESOME!

Keep checking back every couple of minutes. Soon you will be able to see that the water has crawled all the way up the paper towel and is beginning to walk back down into the empty cup next to it.

Since the cup on either side of an empty cup has colored water in it, the two colors begin to mix in the empty cup. So cool!

Keep coming back throughout the two hours or soon and observe what is happening.

Question to Ask

What do you think will happen to the water?

What is happening now?

Why do you think the colors are changing?

Why might the water be able to move up against gravity like that?

How this Science Experiment Works

The water moves up the paper towels through a process called capillary action. The paper towel is made from fibers and the water is able to travel through the gaps in the fibers. The gaps in the paper towel act like capillary tubes and pull the water upward. This is what helps water climb from a plant’s roots to the leaves at the top of the plant or tree.

The water is able to move upward against gravity because of the attractive forces between the water and the fibers in the paper towel.

I even removed one of the red cups and made a color wheel so I could introduce the kids to that as well.

I hope your kids have a great time with this super cool walking water science experiment!

Other Cool Science Experiments for Kids

This rainbow  Walking Water Science Experiment  is one of our most popular science activities!

Try this super simple  Oobleck recipe  that only requires two household ingredients!

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You can also make a rainbow of flowers with this super cool  color changing flowers experiment !

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Did you know you can put paper under water and it will stay dry? Give it a try with this keep paper dry under water experiment . The kids love this cool trick!

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Walking Water Experiment

March 26, 2015 By Emma Vanstone 18 Comments

Every now and then we like to try a more ‘traditional’ science experiment and walking water is one I’ve been trying to catch on video for ages. This super simple experiment works quickly and is very impressive. The science behind it, can be a bit tricky for little ones, but you could start by spilling a little bit of water on a table and demonstrating how the paper towel absorbs the water.

Glasses or jars of the same size

Paper towel

Food colouring

Place coloured water into the glasses on the outside, leaving the middle one empty.

Cut a piece of kitchen roll in half and fold up each.

Place a piece of kitchen roll so it runs from the glasses with water into the empty one.

Sit back and watch.

Can you predict the colour of the water in the middle glass.

Is it faster if you wet the paper towel first?

Would this work if you used a more viscous liquid, vegetable oil for example?

What happens if you use a thicker paper towel?

Why does this work?

The water travels up the kitchen roll by a process called capillary action. The water moves against gravity along the tiny gaps within the fibres of the kitchen roll. Water molecules bind to the paper towel through a process called adhesion, but also stay close to each other as they are cohesive. The gaps in the towel act like capillary tubes, pulling the water upwards.

Another example of this process is where water travels from the roots of a plant to the leaves, we call this transpiration , which is driven by capillary action.

Last Updated on April 5, 2016 by Emma Vanstone

Safety Notice

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

Reader Interactions

November 02, 2015 at 10:30 pm

a producer for walking water

December 07, 2015 at 7:14 pm

its an amazing easy last minute science project

January 09, 2016 at 7:18 pm

love this but can’t do it since someone else did it are there any similar ones I need it asap

May 05, 2017 at 6:21 pm

Ya u can do this

January 20, 2016 at 4:06 am

can I see a sience board about this?

May 12, 2016 at 9:00 am

I’ve tried this several times. The colors are mixing in the wrong cups. For example I have a red cup, empty one in the middle, then a blue at the other end to make purple. It’s making purple in the blue cup. The middle cup becomes blue instead of mixing with the red and turning purple. What am I doing wrong?

May 05, 2017 at 6:22 pm

What you are doing wrong is you need to put them farther apart on your sides then they will not mix

October 18, 2016 at 6:11 pm

My son is doing this project and although the blue and read didnt turn purple, (it turn a very light color) we are still going to continue with it. The purpose of the project is to show how water travels, right. The purpose isnt to see what color the next color will be, although the colors are beautiful : ) We did 7 cups instead. It looks great!!

November 02, 2016 at 10:55 pm

this is the most coolest thing I have ever seen! I can really use this for a science fair!

December 30, 2016 at 7:40 pm

man this experiment is taking a long time to do for a science fair. I wish I can change my experiment for my science fair, but apparently I CAN’T!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

March 29, 2017 at 3:55 am

Thanks to Sheila Couch… I need to experiment where the colors go to make the correct colors in the school science fair… How sad how no one answered Sheila Couch’s question… I guess I have to guessing what goes where…

September 25, 2017 at 1:03 pm

I’m going to do this for my science project this year its about to look lit!

October 02, 2017 at 1:11 pm

I’m about to do a project on this so its about to be lit on my board! 🙂

October 07, 2017 at 5:07 am

Interesting about science and also curiousness !! Wonderful experiment can do with home supplies..

January 12, 2018 at 2:31 pm

Good prediction

January 12, 2018 at 2:34 pm

I’re gonna use it

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Science Experiments

Color Changing Walking Water Science Experiment

Science or magic? This super quick, gravity defying experiment may surprise young scientists and work like magic, but don’t worry! The color changing walking water experiment is science through and through and fun for all ages.

Based on the very popular Walking Water Science Experiment using two glasses, you can observe the water walking AND changing color with only a few supplies you probably already have in your kitchen. This article includes a video to show you just how easy it is with detailed step-by-step instructions and the scientific explanations you need to understand how it works!

JUMP TO SECTION: Instructions | Video Tutorial | How it Works

Supplies Needed

• 3 Glasses of Equal Height
• Paper Towels
• Food Coloring (Blue & Yellow)

Color Changing Walking Water Science Lab Kit – Only $5

Use our easy Color Changing Walking Water Science Lab Kit to grab your students’ attention without the stress of planning!

It’s everything you need to  make science easy for teachers and fun for students  — using inexpensive materials you probably already have in your storage closet!

Color Changing Walking Water Science Experiment Instructions

Step 1 –  Prepare two strips of paper towel between 1 and 2 inches wide. Tip: We used one section of paper towel and folded it in half and then in half again until it was the correct width. Set the paper towel strips aside and gather the rest of the supplies

Step 2 – Next, Position your three empty glasses about 2-3 inches apart. Pour water into the two outside glasses until they are halfway full. Leave the middle glass empty.

Step 3 – Add a few drops of food coloring to the water. Add blue food coloring to one glass and yellow food coloring to the other glass. Stir the water until the food coloring is fully combined.

Helpful Tip: If you don’t have blue & yellow food coloring, you can use red & yellow or red & blue. 

Step 4 – Take one of the strips of paper towel that you prepared in step 1. Place one end of the paper towel into the glass with the blue water. Then place the other end into the glass that is empty.

Step 5 –  Take the other strip of paper towel that you prepared in step 1. Place one end of the paper towel into the glass with the yellow water. Then place the other end into the glass that is empty.

Take a moment to make some observations. What happened to the paper towel that was placed in the water? Do you think it is possible for the water in the first glass to move to the empty glass? What do you think will happen if the water moves to the middle glass? Write down your hypothesis (prediction) and then leave the glasses to sit and come back to check on them in about an hour.

Step 6 – Return to the glasses and observe what has happened. What happened during the hour you were waiting? What do you think will happen if you wait a little longer. Do you think all the water in the outside glasses will move to the middle glass? Why or why not? Write down your hypothesis (prediction) and then leave the glasses to sit and come back to check on them in two hours.

Color Changing Walking water Science Experiment Video Tutorial

How Does the Experiment Work?

Why Does the Water Move Between Glasses? The water appears to defy gravity, but in reality, it moves because of a process called capillary action . Water is able to move against the force of gravity because water molecules stick to each other AND they stick to the fibers of the paper towel. As water molecules are attracted to the fibers of the paper towel, they pull other water molecules with them. The adhesive forces between the water and the fibers of the paper towel are stronger than the cohesive forces between the water molecules. This allows water to travel from one cup to another.

Capillary action is the combined force of attraction among water molecules and with the molecules of surrounding materials.

Why Does Water Change Color? Did you know that three basic colors can combine together to make any other color? These three basic colors are red, blue and yellow. They are referred to as primary colors. When two primary colors combine in equal amounts, they produce a secondary color. In this experiment, we chose blue and yellow (two primary colors) for the outside glasses. When the blue and yellow water mixed in the middle glass it turned green (a secondary color).

More Science Fun

Eventually, the water will stop moving over once both cups are filled with the same amount of water. Expand on the experiment, by estimating how long it will take for the water to move to the second jar. Then set a timer and find out how close your estimate was.

You can also try this experiment with other colors!

Red + Yellow = Orange Red + Blue = Purple

In addition, you can also try these other fun experiments that contain mixing colors:

• Coloring Changing Water Science Experiment – Science or magic? Try this experiment at home with your kids and watch their eyes light up as you pour the liquid into the bowl and “create” a new color.
• Discover How Colors are Made   – This is a simple experiment that demonstrates how different colors are made.

I hope you enjoyed the experiment. Here are some printable instructions:

Instructions

• Prepare two strips of paper towel between 1 and 2 inches wide. Tip: We used one section of paper towel and folded it in half and then in half again until it was the correct width.
• Once you have your two paper towel strips ready, set them aside.
• Next, Position your three empty glasses about 2-3 inches apart.
• Pour water into the two outside glasses until they are halfway full. Leave the middle glass empty.
• Add a few drops of food coloring into the water. Stir the food coloring until the water is all one color. Tip: Use blue food coloring in one glass and yellow in the other.
• Take one of the strips of paper towel that you prepared in step 1. Place one end of the paper towel into the glass with the blue water. Then place the other end into the glass that is empty.
• Take the other strip of paper towel that you prepared in step 1. Place one end of the paper towel into the glass with the yellow water. Then place the other end into the glass that is empty.
• Observe the experiment right away. Do you notice that the water is “walking” up the paper towel? Now, leave the glasses alone and come back to check on them in an hour or two.
• Return to the glasses and observe what has happened.Tip: The longer you wait to check on the glasses, the more water will have moved to the middle glass. The water will stop moving over when all of the cups are filled with the same amount of water.

Reader Interactions

December 26, 2016 at 5:57 am

I want many science experiments for my kids.Thanks for your sharing.

December 10, 2019 at 7:33 pm

Thank you because I really needed something to do for my science fair and now i’m good to go

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Walking Water Experiment – How does it work?

Water appears to magically defy gravity and move upwards. It actually does defy gravity – but we understand the magic! The magic is called capillary action .

What causes water to walk?

Water walks because…

• water molecules are attracted to each other,
• water molecules are attracted to the molecules that make up paper, and
• water molecules are more attracted to the molecules that make up paper than they are too each other.

So, when the paper towel touches the water, the water is pulled towards it. Water molecules also attract each other, so the water pulls more water molecules with it and these water molecules pull more water molecules and so on, creating movement of water up the paper.

This movement of water up the paper towel is also helped by the air spaces in the paper towel – the gaps between the paper molecules. Water pulls itself up into these gaps where is is then able to reach the paper molecules that surround the gap where it is again pulled towards the paper molecules and into the next gap and so on.

The food coloring, which is in the water, moves because:

• they are also attracted to paper molecules, and
• they are also moving along with the movement of the water molecules.

When molecules of the same type are attracted to each other this is called  cohesion .

When molecules of different types are attracted to each this is called  adhesion .

Why are water molecules attracted to each other?

Water molecules are in a tug of war with themselves. Water is made up of oxygen and two hydrogen molecules. Oxygen is a big strong tough molecule and hydrogen is a much smaller, weaker molecule. Oxygen is winning the tug of war by pulling electrons (which are negatively charged) closer to itself and, in doing so, oxygen is becoming slightly negative.

Hydrogen, on the other hand, is losing the tug of war; the electrons are being pulled away from it, so it is becoming slightly positive. Water molecules are therefore slightly negative on the oxygen side of the molecule and slightly positive on the hydrogen side of the molecule – like a tiny magnet. They are not actually magnetic, it is an electric charge, but magnets are a useful analogy. When a negatively charged oxygen atom is attracted to a positively charged hydrogen atom on another water molecule, this is called hydrogen bonding .

Why are water molecules attracted to paper molecules?

Paper molecules, called cellulose, also have these oxygen-hydrogen tug of wars going on. These tug of wars create charged regions on the cellulose molecules that attract the water molecules, just like water molecules are attracted to each other.

Why are water molecules more attracted to paper molecules than each other?

Paper molecules, cellulose, are covered in oxygen-hydrogen tug of wars. They are everywhere on the cellulose molecule. This makes it very attractive to water. It is likely that a number of these oxygen-hydrogen groups attract a single water molecule.

Why does the paper get wet before the color arrives?

You may have noticed the paper towel gets wet ahead of the food coloring. If you haven’t check it out next time you do it. The movement of the water molecules carries the food coloring molecules along with it but the food color molecules move slower than the water because they are so much bigger than the water molecules and find it trickier to move around the paper molecules.

Rainbow Walking Water Experiment

This experiment is so simple to set up, and so rewarding to watch. Whilst it takes a little time (up to two hours) to complete, it kept my kids interested as they popped in to check on progress. You do start to see the effect straight away.

What do you need for the walking water experiment?

• Clear cups – glass or plastic. It is best if they are the same size. If you wish to do the rainbow walking water version like we did, you will need six.
• Food coloring
• Paper towel. We used only three pieces. We cut each piece in half, then folded each half into thirds lengthways. Do whatever fits best in your cup. We needed to chop an inch or so off the end of ours so it fitted comfortably in the cup.
• Extra paper towel for cleaning the spoon

How to do the walking water experiment?

• Arrange your cups in a circle. Add water to every other cup, i.e. to three of the cups. Try to get the same amount of water in each cup.
• Add food coloring to the cups with water. Primary colors give the rainbow effect, but experiment however you like. Stir the water to make sure the food coloring is evenly mixed (remember to wipe the spoon between cups so the colors don’t transfer).

• Fold the strips of paper towel and place one end in a paper cup and the other end in the adjacent cup, like this:

• You will start to see movement straight away. Watch as the water creeps up the towel and collects in the neighboring cup. See the earlier part of this post for an explanation of how this works. Notice the clear line between the colors in the previously empty cups:

• After a few hours

• To see the experiment at speed, see the video below:

You may have some further questions – my children did:

• Will the water keep walking and all the cups end up the same color?
• Does the water stop walking? If so, why?
• What happens if your towel is already wet
• What happens if you put some cups lower than other cups

Let’s consider…

Here is a side view taken late in the experiment:

It is a bit tricky to see, but do you notice that the levels are all the same? Why is that?

Why does the water stop walking?

At a certain point you will notice that the walking water stops. The water does not completely move from one container to the other. The water stops walking when the level of each container is the same. The forces that move the water one direction have become balanced with the forces moving the liquid the other direction, which is why the levels are the same.

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Super Cool Walking Water Science Experiment For Kids * ages 3+

This super cool walking water science experiment is so simple to set up and is an excellent way to demonstrate capillary action and transpiration to kids. My kids were totally amazed at the outcome as the water appears to move from one cup to another!

MATERIALS NEEDED (affiliate links):

Red, yellow & blue food coloring

6 clear glasses

Paper Towels

WHAT TO DO:

1. Start by adding water to three of the cups so that they are about 3/4 full of water.

2. Alternate each cup containing water with an empty cup and arrange them in a circle.

3.Then add a few drops of food coloring to each cup so that one cup is red, one is yellow and one is blue.

4. Next take paper towels and fold them in half or fourths to make long strips.

5. Link all the cups together using the paper towels by placing one end of each paper towel in each cup.

6. Wait several hours or overnight and watch how the water travels through the paper towels and mixes to form new colors. Amazing! 😲

This activity is great to do any time of the year but really fun to do in the spring for a rainbow themed activity.

WHY IT WORKS:

The water is able to move up and through the paper towel because of a process called capillary action. The water travels up the tiny gaps in the fibers of the paper towel. The water molecules are cohesive so they stay close to each other, but they also bind to the paper towel through a process called adhesion. This process is similar to the way water travels from the roots of the plants to the leaves called transpiration.  The gaps within the paper towel act like the capillary tubes of plants and pull the water upwards.

Check out our experiment with celery to demonstrate transpiration!

Check out our other fun science experiments !

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Rainbow Walking Water Experiment

Simple science starts here! This  walking water experiment is incredibly easy and fun to set up for kids. All you need are a few simple supplies you can find in your kitchen cupboards. Watch the water travel as it makes a rainbow of color, and learn about capillary action too! We love easy science experiments for kids!

What You Will Learn

The walking water experiment is a fantastic way to introduce kids to several key scientific concepts:

Capillary Action : This experiment demonstrates capillary action, which is the ability of water (or other liquids) to move upward against gravity through narrow spaces, such as the gaps between paper towels or the fibers of a paper towel.

Absorption : Kids can learn about absorption, which is the process of one substance being taken up by another substance. In this experiment, they observe how water is absorbed by the paper towels and then transported from one cup to another.

Color Mixing : The walking water experiment also allows for exploring color mixing. Using colored water in the cups, kids can observe how the colors blend as the water travels through the paper towels, creating new colors that overlap.

Properties of Water : Through this experiment, kids can learn about the unique properties of water, including cohesion (water molecules sticking together) and adhesion (water molecules sticking to other substances, like paper towels).

Experimental Method : It introduces children to the scientific method by encouraging them to make predictions, conduct experiments, and observe and analyze the results.

Watch the Walking Water Video:

Walking water experiment.

If you want to make this into a walking water science fair project where you are using the scientific method, you need to change one variable. You could repeat the experiment with different types of paper towels and observe the differences. Learn more about the scientific method for kids here .

Walking Water Experiment Hypothesis Example: “I predict that if I place pieces of paper towel in cups filled with different colored water and connect them, then the water will move up the paper towels and travel from one cup to another.

• Test Tubes and Rack (clear plastic cups or mason jars work well too!)
• Food Coloring
• Paper Towels
• Timer (optional)

Instructions:

STEP 1 . You can set up as many or as less jars as you like for this part.

We used 9 test tubes of primary colors (3 x red, 3 x yellow, 3 x blue). We added red, yellow, and blue food coloring (one color per test tube) in a pattern.

Give each test tube (or glass or cup) a little stir to distribute the color evenly. Try to put the same amount of food coloring in each container!

STEP 2. Cut thin strips of paper towel to fit in the test tubes. If you are using glasses or cups, you can judge the best size strip to fit what you are using.

Place the paper towel strips into the test tubes. There will be two ends in each tube.

STEP 3 . Wait and watch what happens. At this point, you can set up a stopwatch to make note of how long it takes for the colors to meet and mix.

Once you have inserted the towels, it’s the perfect time to talk about what your kids see happening (observations). Do they want to improve their hypothesis or have new ideas about what might happen?

How Long Does It Take?

The whole process starts pretty quickly, but it does take a while for the colors to begin to mix. You may want to leave it and return to see the colors mixed.

This would be a great time to pull out the watercolors and do some color mixing art! Or how about setting up a homemade lava lamp experiment while you wait?

Make sure to check on your walking water science experiment every once in a while to see the changes constantly occurring. The kids will be amazed at how the water seems to defy gravity!

The Science Behind Walking Water

Walking water science is all about capillary action , which also can be seen in plants. You can even check out our celery and food coloring experiment to see this!

What is capillary action? Capillary action is the ability of a liquid to flow upward against gravity in a narrow space, like a thin tube or a porous material. Capillary action can happen due to combining two main forces: cohesion and adhesion.

Cohesion is the attraction between molecules of the same substance. In the case of water, water molecules are strongly attracted to each other, creating a sort of “pull” that keeps the molecules together.

Adhesion is the attraction between molecules of different substances. Water molecules are also attracted to the surfaces of materials like glass, paper, and plants.

How Does the Water Walk?

The colored water travels up the fibers of the paper towel. The gaps in the paper towel are similar to the capillary tubes of a plant that pull the water up through the stems. The fibers of the paper towel help the water move upward which is this walking water experiment looks like it is defying gravity. How else does water move up the tree?

As the paper towels absorb the colored water, the water travels up the towel strip. It meets up with the other colored water that has traveled up the neighboring strip. Where the primary colors interact, they turn into the secondary colors. Both colors will continue to travel as long as the towel fibers will absorb the water.

We left our walking water science experiment out overnight and had a mucky-looking puddle of water underneath the rack the next day. The paper towels had become oversaturated!

Free Printable Junior Scientist Guide!

Using the Scientific Method

The scientific method is a process or method of research. A problem is identified, information about the problem is gathered, a hypothesis or question is formulated from the information, and the hypothesis is put to test with an experiment to prove or disprove its validity. Sounds heavy…

What in the world does that mean?!? The scientific method should be used as a guide to help lead the process. You don’t need to try and solve the world’s biggest science questions! The scientific method is all about studying and learning things right around you.

As kids develop practices that involve creating, gathering data evaluating, analyzing, and communicating, they can apply these critical thinking skills to any situation.

To learn more about the scientific method and how to use it, read more here.

Even though the scientific method feels like it is just for big kids…

This method can be used with kids of all ages! Have a casual conversation with younger kiddos or do a more formal notebook entry with older kiddos!

More Fun Water Experiments to Try

Check out our list of science experiments for Jr Scientists!

• Color Changing Flowers
• Sink or Float Buoyancy
• Salt Water Egg Float
• Candle Rising Water Science
• Sugar Water Rainbow (Density)
• Oil and Water

Printable Science Projects For Kids

If you’re looking to grab all of our printable science projects in one convenient place plus exclusive worksheets and bonuses like a STEAM Project pack, our Science Project Pack is what you need! Over 300+ Pages!

• 90+ classic science activities  with journal pages, supply lists, set up and process, and science information.  NEW! Activity-specific observation pages!
• Best science practices posters  and our original science method process folders for extra alternatives!
• Be a Collector activities pack  introduces kids to the world of making collections through the eyes of a scientist. What will they collect first?
• Know the Words Science vocabulary pack  includes flashcards, crosswords, and word searches that illuminate keywords in the experiments!
• My science journal writing prompts  explore what it means to be a scientist!!
• Bonus STEAM Project Pack:  Art meets science with doable projects!
• Bonus Quick Grab Packs for Biology, Earth Science, Chemistry, and Physics

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i was wodering where can i buy this Test Tubes and Rack

This looks like such a cool activity!

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Walking Water Rainbow Science Experiment

Let’s make a walking water rainbow! There’s no better way for little scientists to learn about capillary action and color mixing than by making water walk (yes – walk!) in this colorful rainbow science experiment. This science experiment is a favorite of ours because it’s so easy to set up and the results are almost immediate.

Check out the simple step-by-step below and then gra b 30 more jaw-dropping (but easy prep!) science experiments kids will love from our shop!

Getting Ready

To prep, I gathered our supplies:

• 6 wide-mouth glasses or jars
• Paper towels (use the kind where you can select a size)
• Food dye or liquid water colors (red, yellow, and blue)

I grabbed the six small glasses first .  We’ve had success using wide-mouth drinking cups and canning jars, too.  Even though they all worked, just remember that bigger glasses will need more food coloring.

I ripped off six sheets of paper towel and folded each sheet in thirds, lengthwise.

We were using pretty small glasses, so I cut a few inches off the folded paper towel so it would fit in the glasses.

It’s a good idea to test your paper towel strip to make sure they fit properly in your glasses.  They should be able to go from the bottom of one jar to the next without sticking up in the air too much. The paper towel on the left shows the just-right height.  It’s important to set up this rainbow science experiment for success!

Making a Rainbow

This colorful rainbow science experiment is so simple and quick, it’s perfect for even the youngest little scientists.  My 3 year old, Q, couldn’t wait to get started.

First, I had him line up the glasses and fill the first one with a good squirt of red watercolor , the third with yellow, and the fifth glass with blue.  We left the other glasses empty.

Next, I helped Q add water to the glasses with color until the colored water almost reached the top.

We moved the glasses into a circle and added the paper towels .  Starting with the red, we added one end of the paper towel and then put the other end in the empty glass next to it.

We continued around until the last paper towel was placed into the red glass.

We saw the color wick up the paper towel right away.  This rainbow science experiment doesn’t take long to get going!

After another several minutes, the colored water had almost travelled the whole length of each paper towel.

Five minutes later, the water had traveled all the way up and then down the paper towel and was dripping into the empty glass.

The yellow and red water dripped into the empty cup to make orange!  It made for a good lesson on color mixing.

After another five minutes, we could see the water level had dropped in the red, yellow, and blue glasses and rose in the once empty glasses as the water continued to travel from the more full glasses to the less full glasses.

We grabbed a snack and watched our beautiful rainbow science experiment during the next 20 minutes. The water continued to walk from the primary colored glasses to fill the secondary-colored glasses until all the jars were filled equally.

Not Working?

If you aren’t seeing much movement within a few minutes, it may be that you need to add more water to your colored water glasses.  It really needs to be almost at the top for the water to walk quickly.  So try topping off those glasses and seeing if that gets things moving.

If you see the water moving up the paper towel but it seems like it’s taking forever , it may be the type of paper towel you are using.  You want a paper towel that will really hold a lot of water.  We have used Bounty Select-a-Size and Target’s Up and Up Brand Select-a-Size with success.

It really is worth the extra effort of trying different cups and paper towels to get this activity to work.  And once you have had success, don’t throw out those beautifully-colored paper towels or the colored water!  We gently squeezed out our paper towels and let them dry in a heap on a baking sheet.  We ended up with gorgeous tie-dyed looking paper towels to use for crafts and we used the leftover water as watercolors for painting with later.

The Science Behind It

This rainbow science experiment is as magic as the science behind it.  The colored water travels up the paper towel by a process called capillary action . Capillary action is the ability of a liquid to flow upward, against gravity, in narrow spaces.  This is the same thing that helps water climb from a plant’s roots to the leaves in the tree tops.

Paper towels, and all paper products, are made from fibers found in plants called cellulose .  In this demonstration, the water flowed upwards through the tiny gaps between the cellulose fibers.  The gaps in the towel acted like capillary tubes, pulling the water upwards.

The water is able to defy gravity as it travels upward due to the attractive forces between the water and the cellulose fibers.

The water molecules tend to cling to the cellulose fibers in the paper towel.  This is called adhesion .

The water molecules are also attracted to each other and stick close together, a process called cohesion .  So, as the water slowly moves up the tiny gaps in the paper towel fibers, the cohesive forces help to draw more water upwards.

At some point, the adhesive forces between the water and cellulose and the cohesive forces between the water molecules will be overcome by the gravitational forces on the weight of the water in the paper towel.  

When that happens, the water will not travel up the paper towel anymore. That is why it helps to shorten the length that colored water has to travel by making sure your paper towel isn’t too tall and making sure you fill your colored liquid to the top of the glass.

Rainbow Science Activity Extensions

Turn this demonstration into a true experiment by varying the water level (volume) you start with and seeing how long it takes the water to reach the empty glass.

Or start with the same volume of colored water and change the brand, type (single vs double ply, quilted vs not) or length of paper towel to see how long it takes for the water to “walk” to the empty glass.

You could even use the same volume of water, same length and brand of paper towel but vary the height of the filled glass , by raising them up on books, to see how that affects the speed of the water as it “walks” to the empty glass.

Have you had enough fun with the paper towels?  Try using other paper products to see how the type of paper effects the results.  Try toilet paper, printer paper, newspaper or a page from a glossy magazine.  What do you predict will happen?

Grab a Record Sheet

Help kids keep track of their results by grabbing our free record sheet! Then grab 30 more jaw-dropping (but easy prep!) science experiments kids will love from our shop!

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The Walking Water Experiment For Kids

by Science Explorers | May 24, 2019 | Blog | 0 comments

What is the walking water experiment? An activity involving two cups, some water and some scientific magic, of course! It’s the perfect, low-cost do-it-yourself experiment for you to try with your kids. If you’ve been looking for a way to introduce your children to basic science concepts through hands-on discovery, the walking water experiment will do the trick.

If you’re wondering if the walking water experiment is just for kids, it’s not! This experiment wows people of all ages. It’s never too late to unlock your inner scientist and nurture your intellectual curiosity. Your kids will love seeing how excited you are.

Keep reading to learn more about how to make water walk.

How to Make Water Walk

This experiment is extremely conservative when it comes to materials and preparation. To set up for this experiment, you will need the following:

• Two glasses of equal size
• Water (any temperature/kind of water works)
• Blue food coloring
• Paper towel

As you can see, this is a very low maintenance experiment. With almost no cleanup, this is the perfect activity to do with your children when you have some free time.

The Walking Water Experiment For Kids: Six Easy Steps

Once you have your materials together, the rest is easy. Follow these simple steps to wow your kids and show them the possibilities of science:

• Set your two identical glasses about 2 inches apart. Pour water into one of the cups until it’s halfway full.
• Add a few drops of your favorite food coloring to the water.
• Stir the food coloring until the water is one color.
• Take a strip of paper towel and fold it until it’s 1 to 2 inches wide.
• Place one end of the paper towel strip into the colored water and the other end into the empty glass. Let them sit for one hour.
• Return to the glass and observe what happened.

Spoiler alert: you will find that half of the colored water traveled to the other side of the cup! The paper towel will also be the same color as the water you started with.

The Rainbow Walking Water Experiment For Kids

If you want to take this experiment to the next level, you can take on the rainbow edition. Place seven cups two inches apart each. Then, follow these instructions:

• Fill the 1st, 3rd, 5th, and 7th cup halfway with water.
• Add five drops of red food coloring to the 1st and 7th cup.
• Add five drops of yellow food coloring to the 3rd cup.
• Add five drops of blue food coloring to the 5th cup.

For this experiment, you need six sections of paper towel. Follow the same protocol as steps four and five from the above directions. Leave the cups alone for one hour, then return to make your observations.

Your kids will be very excited to come back to a fully formed rainbow! As the water travels from one cup to the other, the colors mix. This is also a prime opportunity to teach some art fundamentals: primary and secondary colors. The three primary colors are red, yellow and blue. Secondary colors are shades you can make from the three primary colors, like orange, green and purple.

The Science Behind the Walking Water Experiment

At first, this experiment appears to defy gravity.

How does the water get from one cup to the other? With a little bit of magic called capillary action. Essentially, the adhesive force between the paper towel and the water are more powerful than the cohesive force inside the water itself. This results in the paper towel pulling the water up. The water keeps traveling up the paper towel, across the bridge and into the other cup.

Ready to Try the Walking Water Experiment?

Now that you know how to make water walk, it’s time to introduce your kids to the magic of science. If you think your child would benefit from a more immersive science experience,   our science summer camps   might be the perfect fit. We also run   after-school science clubs   for kids demonstrating early signs of scientific interest. If your child is a budding scientist, enrolling them in our club is the best way to nurture their growing brain.

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Walking Water Experiment

We love simple science experiments. And this one is really easy to set-up and the kids are always amazed at the end result. Learn about color mixing and capillary action in this easy walking water experiment!

RELATED: Grow a Rainbow Experiment 

Walking Water Science Experiment

This science project is fun for kids of all ages to try! Kids will be amazed at the rainbow created using capillary action. You can also use this activity to teach about color mixing and rainbows.

See also our Grow a Rainbow experiment.

Watch the Video Tutorial

Here is what you will need for this activity:  

• Paper Towel – 6 folded half sheets
• Food Coloring – we like the liquid gel food coloring (you just need 1 drop) but regular food coloring works too
• 7 Small Clear Cups or Glasses

What is the Science Behind This Experiment?

This science experiment is a great example of coloring mixing and capillary action.

Kids can learn about how secondary colors are formed when the orange, green and purple colors are made in the empty cups.

Capillary action is what makes the dye move up the paper towel.  The water moves upward through the paper towel, lifting the food dye molecules with it. This same phenomenon is what allows trees to get water from the ground with their roots. Paper towels are made from fibers found in plants, called cellulose.

How to do the Walking Water Experiment

1. Start by filling up 4 clear cups with water.

Fill the water to almost the top of the cup.

The more water there is, the faster the walking water will travel.

2. Add 1 drop of red food coloring to two of the cups, 1 drop of blue food coloring to one of the cups and 1 drop of yellow to one of the cups.

If using regular food coloring you may need to add a few drops.

For the red and blue, make sure this is not too concentrated.

Once the colors mix, if they are too concentrated then the purple will look more black than purple.

3. Place the cups in a line starting with red on each end.

Line them up like this: 1. Red 2. Empty Cup 3. Yellow Cup 4. Empty Cup 5. Blue Cup 6. Empty Cup 7. Red Cup

When the colors mix then the order of the rainbow will show this way.

4. Fold over 6 pieces of paper towel (half sheets) and trim about 1/4 off the end so they are not too long.

5. Place a paper towel into each cup and connect with the empty cups.

6. The water and dye will immediately start to move up the paper towel into the empty cups.

Blue and red will mix to make purple.

Blue and yellow will mix to make green.

And red and yellow will mix to make orange.

7. Wait 2-3 hours for the empty cups to fill with the new color that is mixed from the other 2 cups.

Now your walking rainbow is complete! You can now see each color from the rainbow in the cups and your empty cups have now been filled with the secondary colors – orange, green and purple!

Note – if you would like to do the experiment in a circle instead of a straight line to save space, just make 1 red cup and place the cups in a circle (as shown in the first image).

Kids will love watching the water travel and seeing the new colors being made in this easy science experiment!

More Science Experiments for Kids

Try this fun and easy Grow a Rainbow Experiment . You only need washable markers and paper towel!

For another fun experiment, make some oobleck! 

Try a rainbow rain cloud in the jar experiment!

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Fluffy Slime Recipe

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