salt sugar and water experiment

Salt vs. Sugar – A Dissolving Problem

This formative assessment looks at two household chemicals (table salt and sugar) and compares their properties while looking at how they dissolve in water. The “Salt vs. Sugar” formative assessment explores students’ thinking about the question “How does structure influence reactivity?” The main idea that is being targeted is for students to think about what is happening at the molecular level during the solution process. This activity is important for students because it helps create a context for what some of the vocabulary and concepts mean by providing tangible examples of these concepts (such as the concept of saturation).

Teacher reflections

Because of the asynchronous flow of the remote learning period, this was challenging to be able to fully communicate with my students during this activity to fully understand their chemical thinking as they were working. I think this activity could have worked better in a synchronous remote learning environment, however, because some students may not have access to the materials needed for this activity at home, materials could have been prepared in a way in advance to get them to the students so they could perform this activity at home. Doing it in a synchronous environment could have also led to interesting suggestions, ideas, or follow ups that students might have thought about on the fly as they were doing the activity. Often times, these ideas and thoughts might be missed in an asynchronous environment where students have time to consider their answer in what they deliberately share at the end, and it might be refined and missing elements of their chemical thought process. Outside of the asynchronous vs synchronous challenge of the formative assessment, I found this formative assessment rather successful in giving students an opportunity to explore aspects they know about molecules and how they interact with each other (specifically, polar intermolecular forces) and see if they can make a model or conclusion about why these chemicals dissolve differently.

Remote learning

During the Remote Learning session, Google Classroom was the primary tool for instruction and organization of learning materials. For this specific Formative Assessment, two documents were provided to students: one was a Google Doc with the questions and instructions for the activity, the other was a Google Slides presentation containing several pictures that were taken during a demo of the activity (in case some students did not have access to the materials at home for this activity, they could work with the image slides to make their observations). One consideration to alter this formative assessment would be to convert the questions to a Google Form instead to perhaps make it easier for some students to input their answers, especially if they didn’t have access to a computer but could use a phone (students had indicated that Google Docs can be very difficult to use on a phone’s touchscreen).

Examples of student work

Pre-activity questions

Post-lab questions

General Safety

For Laboratory Work:  Please refer to the ACS  Guidelines for Chemical Laboratory Safety in Secondary Schools (2016) .  

For Demonstrations: Please refer to the ACS Division of Chemical Education Safety Guidelines for Chemical Demonstrations .

Other Safety resources

RAMP : Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies

Science Practice: Analyzing and Interpreting Data

Analyzing data in 9–12 builds on K–8 and progresses to introducing more detailed statistical analysis, the comparison of data sets for consistency, and the use of models to generate and analyze data.

Analyzing data in 9–12 builds on K–8 and progresses to introducing more detailed statistical analysis, the comparison of data sets for consistency, and the use of models to generate and analyze data. Analyze data using tools, technologies, and/or models (e.g., computational, mathematical) in order to make valid and reliable scientific claims or determine an optimal design solution.

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The rainbow density tower experiment is a great way to teach your kids about how the density of water can change when something is dissolved in it and is a good way to introduce older children to the idea of how salty seawater and freshwater interact in our oceans. Max was amazed by the result of this experiment, and had thousands of questions about what was going on! This experiment can be performed with salt or sugar. It can be performed with at least two different types of food colouring, but the more you use the better it looks! Why don’t you try to make 3 or 4 layer density tower, or even 6 layer tower as we did in the video below.

It’s important to consider the volumes of the glasses and the tall beaker. Ideally, the volume of water in It’s important to consider the volumes of the glasses and the tall beaker. Ideally, the volume of water in the glasses will fill the tall beaker/vase. If you don’t have the correct equipment for this, just make sure you don’t accidentally fill the tall beaker/vase up only a few of your mixtures! Ideally, an equal volume of each coloured liquid is added. 

Fill up the glasses with cold tap water. Remember – use one glass for each different colour of food colouring that you are using!

Add a few drops of food colouring to each of the glasses, so the water in each glass turns a different colour.

Add the sugar or salt to the glasses. This should be done in an orderly fashion so that the water in the glasses becomes progressively saltier (or sugarier). The first glass should be left without salt/sugar. Using a teaspoon to measure, add one teaspoonful of sugar/salt to the first glass. Add two to the second glass, three to third etc.

Stir each glass thoroughly with the teaspoon, making sure to wipe down the spoon with a paper towel between glasses. These are now ready to be transferred to the tall beaker/vase!

Pour the glass with the most sugar/salt added into the tall beaker/vase.

Add torn up pieces of blotting paper to the tall beaker/vase. You should add enough that they create a near-continuous surface on the top of the water in the beaker.

Now it’s time to prepare the funnel. Attach the straw to the end of the funnel with some sticky tape.

Take the funnel and straw and arrange the straw in the beaker so it will feed water to just above the layer of blotting paper. If the straw enters the layer of water below, the layers will get mixed up and the experiment won’t work. Similarly, if you pour the water in vigorously or let the water drop from a height, the layers will be disturbed.

Carefully and slowly begin pouring the second saltiest glass of water into the funnel, raising the staw as the water level rises.

Repeat this process, working from the glasses with the most salt/sugar added, until you get to the one with no salt/sugar added.

Sit back and watch the colourful layers become more and more distinct!

You may also like 8-Layer Density Column

If you liked Rainbow Density Tower, you may like our 8-Layer Density Column experiment too.

This experiment doesn’t just look great, it can teach us a few cool things about water and what happens when something dissolves, and about the concept of density.

When a solid substance like salt or sugar is mixed into the water – it disappears! This is because it is soluble – which is a fancy word that means it dissolves. What happens when the salt or sugar dissolves? It doesn’t just disappear but becomes suspended in the water. The water makes the salt/sugar molecules break apart into smaller pieces, which are then carried apart by the water. Nature likes things that are evenly spread out, so the salt/sugar will mix into the water until it is evenly spread.

Why do the different coloured layers of water stay distinct from one and another, and not mix? The different layers of water have different amounts of salt/sugar added to them. This changes a characteristic of the water known as density. Water with two teaspoonfuls of salt/sugar dissolved in it is more ‘dense’ compared to water with one teaspoonful of water dissolved into it. A good way to imagine salty water is that it is ‘busier’ with salt particles.

More dense, or busier water, is heavier than less dense water. More dense water will want to stay at the bottom of the beaker, and the less dense water will effectively float on top of it. The two liquids will only mix a little but are generally quite happy to stay separate.

When we’re talking about salt/sugar dissolving in water, there are some keywords that we should understand. In this experiment, salt or sugar (or the thing that dissolves) is called a solute , and water (what the sugar/salt dissolves into) is called a solvent. When the salt/sugar is dissolved in the water, a solution is produced. So a solute + a solvent = a solution! 

What happens when sugar or salt dissolves to form a solution? The answer is not as simple as the particles becoming suspended in water. Instead, we have to imagine a salt/sugar molecule and understand what holds it together. Let’s take salt – which is made up of ions of sodium and chloride, which have an ionic bond holding them together (an ionic bond is a force that holds two different particles together through a force similar to that seen in magnets). When salt is added to water, the sodium and chloride ions are more attracted to charged water particles than they are to each other. So effectively the water molecules pull the sodium and chloride ions apart, breaking the ionic bond that holds them together! The same happens with sugar, which has a slightly more complex molecular structure. 

Why do the different coloured layers of water stay distinct and separate, rather than mixing? This happens because the different salt/sugar solutions have different densities. The density of a solution will correlate directly with how much salt/sugar has been added to it. Solutions of different densities won’t mix because the more dense solution will naturally want to sink below the less dense solution (in some ways density can be thought of as how ‘heavy’ a liquid is!). Mixing will occur gradually at the boundary, or if stirred, but otherwise the different solutions are happy to not interact.

This is an interesting concept when we think about salty seawater and the fresh water that is added to the oceans from melting ice (which is fresh, or not salty). Saltwater and freshwater will behave differently – with saltwater sinking deeper in the oceans and freshwater wanting to stay at the surface. This is a very important concept in oceanic science and plays a big part in ocean circulation. Temperature is another important variable in oceanic circulation. If you want to know more about this, google ‘thermohaline circulation.

Water temperature is a variable that can be altered in this experiment and gives a range of interesting results. 

On the one hand, heat helps a solute to dissolve into a solvent. Why not measure how many spoonfuls of sugar or salt will dissolve in a glass of cold water vs a glass of warm water? 

Temperature is also a major control of density. A cold solution will be denser than a warm one, even if they have the same amount of solute dissolved in them. What happens if the temperature of the different solutions is mixed up, with some being warm and others being cold? (Spoiler alert: your nice colourful layers of water will probably mix!). 

Thank you! I will try it with my daughter tonight

Hi John! I am glad to hear this. I am sure you will have a wonderful time together exploring density and rainbows (:

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Salt Water Density Experiment

Can you make a fresh egg float in water? What will happen to an egg in a saturated solution of salt water? Will an egg float or sink in salt water? What is density? What is buoyancy? There are many questions and hypotheses (predictions) to make with this easy salt water experiment, and you can learn about it all with just water, salt, and eggs! Check out all our classic science experiments for more great ideas!

SALT WATER DENSITY EXPERIMENT

Let’s get ready to investigate! Head to the kitchen, open the pantry, and be prepared to get a little salty. And if you are curious about the rubber egg experiment in the video, click here .

YOU WILL NEED:

• 2 Tall glasses big enough to hold an egg

SALT WATER EXPERIMENT SET UP:

STEP 1:  Start by filling one glass about 2/3 of the way full with water. Ask the kids what will happen if you carefully drop an egg into the glass of water. Now go ahead and do it!

STEP 2:  In the other glass, fill to the same height with water. Now stir in 3 tablespoons of salt. Mix well to dissolve the salt! Ask the kids what they think will happen this time and demonstrate!

TIP: Now’s a great time to talk about mixtures. By combining salt and water, you are making a mixture, an important science concept ( Grab a free printable list of science words )!

A mixture is a material made up of two or more substances mixed together. No chemical reaction takes place, and you can separate the substances in the mixture. You can have a mixture of liquids, solids, or gases.

The second egg should float due to the water’s density change!

SALT WATER DENSITY IN THE CLASSROOM

Kids can easily experiment with different objects from around the room. Small plastic items will work best with the measurements of salt and water provided.

If the item still sinks in the salt water, ask the kids what they think! Should they add more salt? Have each kid contribute an item to the experiment!

This is a great experiment to add to your ocean science lesson plans because the ocean is salty!

So many great saltwater density questions:

• Do you float better in salt water?
• What about some of the biggest mammals on earth that float easily in the ocean?
• Does the density of the saltwater play a role?

Why is the ocean salty? The simple answer is that the salt comes from the rocks on the land that has been broken down by erosion and is carries by streams to the ocean.

WHAT IS DENSITY?

Why do some objects sink while another object floats? An object sinks because it is denser or heavier than water and vice versa. Our sink and float experiment is another exciting way to look at items that might surprise you using only water.

Big items that feel light, like a ping pong ball, are less dense than smaller items that feel heavy, like a gold ring. When added to water, objects denser than water sink, and those less dense than water float. Hollow things often float as air is less dense than water. Learn more about what is density.

You can experiment with many objects that sink and float in water, but what happens when you add salt to the water? Can you change whether the object, like the egg, still sinks?

How does salt affect the density of water?

Adding salt to water densifies it. As the salt dissolves in the water, it adds mass (more weight to the water). This densifies the water and allows more objects to float on the surface that would sink in fresh water. This is an example of a physical change !

Do objects float better in saltwater or freshwater?

What other items can you find to test? Most items will generally float in this salt water experiment even if they sink in freshwater. Just look at the egg!

CHECK OUT MORE SIMPLE SCIENCE IDEAS

• Sink the Boat Buoyancy Challenge
• Freezing Point of Water
• Frost on a Can (not just for winter!)
• Sink or Float Experiment
• Do Oranges Sink or Float?
• What Dissolves in Water?

Turn It Into A Science Fair Project

Science projects are an excellent way for older kids to show what they know about science. They can also be used in all sorts of environments, including classrooms and groups.

Kids can take everything they have learned about using the scientific method , stating a hypothesis, choosing variables , making observations , and analyzing and presenting data.

Want to turn one of these experiments into an awesome science fair project? Check out these helpful resources.

• Science Project Tips From A Teacher
• Science Fair Board Ideas
• Easy Science Fair Projects

Helpful Science Resources To Get You Started

Here are a few resources that will help you introduce science more effectively to your kiddos or students and feel confident yourself when presenting materials. You’ll find helpful free printables throughout.

• Best Science Practices (as it relates to the scientific method)
• Science Vocabulary
• 8 Science Books for Kids
• All About Scientists
• Free Science Worksheets
• Science Supplies List
• Science Tools for Kids
• Scientific Method for Kids
• Citizen Science Guide
• Join us in the Club

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

15 Comments

When I click the link to go to your blog from my email, a virus (weird website) keeps popping up. I like your blog. But you may want to check into the virus.

I think Liam’s explanation of water density is perfect – smart kid! These projects are a perfect way to *show* kids the difference, instead of just trying to explain it to them (like you said, nearly impossibly for preschoolers!)

I can see salt water being a big hit around here for experimenting! This looks so fun! Pinning for the future!

Lots of stirring but lots of interesting fun! Thanks for pinning!

Thanks Emma! He’s a smart cookie and likes to see things too understand! Not big on listening a whole bunch just yet 😉

Thanks I will look and see what I can see! Glad you like it!

Very good post. I absolutely love this site. Continue the good work!

I like this experiment but it is not about weight it is about density.

Yes, I have been meaning to update it a bit more. Thank you.

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• Fifth Grade

Lesson 2.1 - Using Dissolving to Identify Substances

Lesson overview for teachers.

View the video below to see what you and your students will do in this lesson. 

Youtube ID: kStOJKoykvM

Downloads:   Lesson Plan (PDF)   |  Student Activity Sheet (PDF)   |  Student Activity Sheet Answers (PDF)   |   Student Reading (PDF)   |   Teacher Background (PDF)   |   Connections to NGSS (PDF)

Students will be able to plan and carry out an investigation to compare the solubility of different substances, and develop and explain a particle-level model to describe the process of dissolving. Students will also be able to explain that substances dissolve by different amounts because of the molecules they are made from.

Key Concepts

• For a dissolving test to be fair, the same amount of each substance being tested, and the same amount of water need to be used.
• The amount of a substance that dissolves in a certain amount of water is a characteristic property of that substance.
•  The different atoms and molecules of a substance give it its characteristic solubility.

NGSS Alignment

• NGSS 5-PS1-3:  Make observations and measurements to identify materials based on their properties.

In earlier grades, students observed and tested objects and materials, and saw that the items could be grouped based on their characteristic properties. In this and the following lessons in Chapter 2, students continue to develop this idea and see that the characteristic properties of a substance can be used to identify the substance.

In this lesson:

• Students are given labeled samples of salt and sugar. They are also given unknown samples marked A, B, and C. One is salt, one is sugar, and the other is alum, which looks like it could be either salt or sugar.
• Students first use a dissolving test to see how salt and sugar dissolve in water. Students then run the same dissolving test on substances A, B, and C; identify the salt and sugar; and conclude that the other substance must be something different.
• Students then see an animation to help explain that the substances are made of different atoms and molecules, so they dissolve differently.

Download the student activity sheet and distribute one per student when specified in the activity. The activity sheet will serve as the Evaluate component of the 5-E lesson plan.

Make sure you and your students wear properly fitting safety goggles.

Clean-up and Disposal

Remind students to wash their hands after completing the activity.

All common household or classroom materials can be saved or disposed of as you ordinarily would. 

Teacher preparation

• 8 clear plastic cups (per student group)
• 3 tall clear plastic cups

Preparing the materials

• Label 5 cups Sugar , Salt , A , B , and C for each group.
• Place 1 teaspoon of sugar and 1 teaspoon of salt in their labeled cups.
• Place 1 teaspoon of alum in cup A, place 1 teaspoon sugar in cup B, and place 1 teaspoon salt in cup C. Do not tell students what is in cups A, B, and C.

Materials for each group

• Sugar in labeled cup
• Salt in labeled cup
• Cup labeled A with alum
• Cup labeled B with sugar
• Cup labeled C with salt
• 3 empty clear plastic cups labeled A, B, and C
• 3 empty cups (to measure and pour water from)
• Graduated cylinder or teaspoon

1. Have a class discussion about how to tell the difference between salt and sugar (without tasting).

Hold up two clear cups of salt and sugar. Tell students that salt and sugar look very similar but, as students know, they are very different.

Ask students:

• Other than tasting the salt and sugar, what test could we do to see how salt and sugar are similar or different? Students may suggest comparing how they smell or comparing how easy or hard it is to crush them. If students do not suggest a dissolving test, you can suggest it. 

Tell students that they will investigate whether it is possible to tell one substance from another based on how much the substance dissolves. Tell students that they will first compare how well salt and sugar dissolve in water. Then they will use their results to figure out what the unknown substances are in cups A, B, and C.  Tell students that one contains salt, one contains sugar, and the other contains either salt, sugar, or something else. Explain that the class will design a dissolving test to try to figure out what substance is in which cup.

Give each student an Activity Sheet (PDF) . Students will record their observations and answer questions about the activity on the activity sheet.

2. Help students design a dissolving test.

Have a discussion with students about the best way to design a dissolving test to see if there is a difference between salt and sugar.  

Question to Investigate:  Can you identify substances based on how well they dissolve in water?  

• If we want to compare the dissolving (solubility) of sugar and salt, should we use the same amount of sugar and salt? Yes
• Should we put them in the same amount of water to dissolve them? Yes
• Should the water be at the same temperature? Yes
• Place ½ teaspoon of salt and ½ teaspoon of sugar into their labeled cups.

Note: A solubility test is normally measured by the mass of a substance that dissolves in a given volume of water. Using volume (1/2 teaspoon) for the salt and sugar instead of mass is probably acceptable for this age group for showing that different substances have different solubilities. In middle school, students can weigh the solutes for a solubility test that uses equal masses.  

• Add 10 milliliters (2 teaspoons) of water to two separate cups.
• At the same time, pour the water into the sugar and salt cups.
• Gently swirl the cups to see whether sugar or salt dissolves the most.

Expected results

The sugar will dissolve completely but some salt will remain undissolved.

• What did you observe? The sugar dissolved completely and faster than the salt. The salt dissolved much more slowly than the sugar and did not dissolve completely, but almost.

3. Help students design and conduct a dissolving test on the substances in cups A, B, and C.

Discuss with students how they should test the substances in cups A, B, and C. Students should understand that they need to test them the same way they tested the sugar and salt so they can compare them to what they saw before.

• Place ½ teaspoon from cup A into empty cup A. Place ½ teaspoon from cup B into empty cup B. Place ½ teaspoon from cup C into empty cup C.
• Add 10 milliliters of water (2 teaspoons) to 3 empty cups.
• At the same time, you and a partner pour the water into cups A, B, and C and gently swirl the cups to see which dissolves most similarly to sugar and salt. Also note whether any of the powders could be something other than sugar or salt based on how it dissolves. 

The substance in cup B dissolved completely and the fastest. It was like the sugar. The substance in cup C dissolved more slowly than the sugar and did not dissolve completely. It was like the salt. The substance in cup A didn’t seem to dissolve much. It dissolved even slower than the salt and there was a lot that didn’t dissolve. It was not like sugar or salt.

• Which cup do you think had the sugar? B
• Which cup do you think had the salt? C
• Which cup do you think had a different substance? A            

Let students know that the other substance is called alum.

4. Explain that the different atoms and molecules of a substance make it dissolve in a characteristic way.

Show the animation  Dissolving Different Substances .

Note: The animation uses two types of models. For the salt, the model shows the sodium and chloride ions as individual spheres with their respective charges. For the sugar and alum, no individual atoms are represented. The structures of these molecules are complicated and made up of many atoms bonded together in complex ways. Therefore, simple shapes of hexagons and diamonds with positive and negative charges are used to represent the molecules of these substances.

Explain that since the atoms and molecules that make up sugar, salt, and alum are different, and have different charges, each substance has a different structure. They also, as a result, interact differently with water molecules. Because each substance is made from different atoms in different arrangements, they dissolve differently. 

5. As a demonstration, have students add salt, sugar, and alum to dirty water to show that alum cleans water more effectively than salt or sugar.

Alum has an interesting property that is different from many other substances. One way to tell the difference between salt, sugar, and alum is to do a water cleaning test.

Materials for the demonstration

• Masking tape
• Plastic spoon for stirring
• Use masking tape and a marker to label the three clear plastic cups  Salt ,  Sugar , and  Alum .
• Add water to the three cups until they are about ¾-full.
• Add about 1 teaspoon of dirt to each cup and stir until the water looks dirty in all the cups.

Demonstration

• Have three students add ½ teaspoon of salt to its labeled cup, ½ teaspoon of sugar to its cup, and ½ teaspoon of alum to its cup.
• Stir the mixture very well in all three cups.
• Let them sit undisturbed and check them in about 15 – 30 minutes.

The water in the container with the alum should look clearer than the water with the salt or sugar. It should only take 10 - 15 minutes to see a noticeable difference.   

This test shows that alum has a characteristic property of being able to make dirty water clearer. It is also another way of telling that the alum is different from salt and sugar even though it looks similar to both.

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FREE K-12 standards-aligned STEM

curriculum for educators everywhere!

Find more at TeachEngineering.org .

• TeachEngineering
• Concentrate This! Sugar or Salt...

Hands-on Activity Concentrate This! Sugar or Salt...

Grade Level: 10 (9-12)

(four 55-minute sessions)

Expendable Cost/Group: US $3.00

Group Size: 2

Activity Dependency: None

Subject Areas: Algebra, Chemistry, Science and Technology

NGSS Performance Expectations:

TE Newsletter

Engineering connection, learning objectives, materials list, worksheets and attachments, more curriculum like this, pre-req knowledge, introduction/motivation, vocabulary/definitions, troubleshooting tips, activity extensions, activity scaling, user comments & tips.

In the field of chemical engineering, it is important to understand the dependency of concentration on the physical properties of a liquid. Small changes (intentional and unintentional) in the composition of a liquid mixture can make dramatic changes to the liquid's boiling, melting or freezing point, density, viscosity or surface tension. Chemical engineers must understand how these changes can impact the function of a substance so they can account for, and design, new substances. For example, small changes can make the difference between your car starting in the winter or not, depending on whether or not the correct chemical composition of anti-freeze or motor oil was used.

After this activity, students should be able to:

• Follow step by step procedures to conduct an experiment.
• Apply the concept of concentration changes to alter boiling point.
• Correctly use units of concentration.
• Calculate solute mass from a known concentration and solvent mass.
• Determine when boiling occurs and measure a liquid's boiling point.
• Apply the understanding of boiling points and altering boiling points to a real-life engineering situation.
• Math competency: Skills and appreciation for data collection used in real life.
• Quantitative literacy: Ability to follow procedures and provide recommendations.
• Engineering applications: Engineering design process, material selection and cost considerations.
• Cultural relevancy: How to follow procedures, collaborative work in small groups and hands-on activities.

Educational Standards Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards. All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN) , a project of D2L (www.achievementstandards.org). In the ASN, standards are hierarchically structured: first by source; e.g. , by state; within source by type; e.g. , science or mathematics; within type by subtype, then by grade, etc .

Ngss: next generation science standards - science.

Common Core State Standards - Math

View aligned curriculum

Do you agree with this alignment? Thanks for your feedback!

International Technology and Engineering Educators Association - Technology

State standards, washington - math, washington - science.

Section 1- Boiling Point Data

Each group needs:

• beaker tongs or hot gloves
• 300 ml beaker
• thermometer
• burner or hotplate
• 200 ml water
• Section 1 Worksheet
• graduated cylinder
• glass stir rod
• aluminum foil (4" x 4" piece) used to form a lid over beaker during boiling

To share with the entire class:

• electronic balance (capable of weighing 200 ml water plus beaker weight)
• salt, approximately 250 g for every other group (each group only tests one solute)
• sugar, approximately 540 g for every other group (each group only tests one solute)

Section 2 - Data Analysis

• Section 2 Worksheet

Section 3 - Design

• Section 3 Worksheet
• salt, approximately 100 g per group
• sugar, approximately 180 g per group

Students should be familiar with:

• Math concepts: line graphs and fractions.
• Science concepts: concentration, mass, weighing practices, boiling point.

However, this activity could be used as a means of introducing some or all these concepts.

(The motivation for this activity is to familiarize students with concentrations by providing opportunities for them to first create solutions and calculate the concentration based on solute mass, test solutions for boiling point, then predict performance of other concentration based on data analysis, and then finally to calculate solute mass based on the needed concentration, and verify their prediction through testing boiling point of the new solution. Students also will understand the importance of determining the cost of a solution and relate this cost analysis to the engineering design process; engineers must optimize cost of materials in designs.)

How do chemical engineers design new materials and products in the lab? The method of test, analyze and validation is common practice in engineering. Today you will be doing the same thing. This gives you the opportunity to explore and understand data analysis in true lab situations where you must try to control as many variables as possible to produce the most accurate results.

What is the connection between chemistry and chemical engineering? (Listen to student ideas.) Chemical engineering is the application of a person's knowledge of chemicals, mixtures and solutions to solve real-world problems. What might be some examples? (Listen to student ideas.) There are so many examples. One example is that chemical engineers design specific anti-freeze and motor oil chemical solutions to help your car work more efficiently and effectively in specific conditions.

Before the Activity

• Gather materials.
• Make copies of Section 1 Worksheet , Section 2 Worksheet and Section 3 Worksheet.
• Test the salt and sugar concentrations to confirm the boiling point curves. Be sure to include the boiling point of the pure water sample.

With the Students

Before start of the lab:

Introduction to Solutions

• Discuss what makes a solution: a solvent plus a solute.
• Give examples of solutions and have students come up with their own examples (use Worksheet 1 to help guide this).
• Describe concentration as a means of describing (defining) a solution. Concentration is a measure of how much of some substance is contained in a mixture.
• Introduce units and decide which ones will be used in the labs.
• Introduce equation to calculate concentration based on masses of solute and solvent (use Worksheet 1 to help guide this).
• Discuss why concentration might be an important property of a mixture and how concentration may change other known properties (density, viscosity, surface tension, boiling point, freezing point). Specifically, use this information to introduce the concept of chemical engineering.
• Salt water fish tanks.
• Saline solutions used in hospitals.
• Why salt is put down on roads in the winter or why we make homemade ice cream by spreading salt on the ice. This is an example of engineering the defined environment- applying what engineers know about melting points and solutions to fix a real-world problem.
• Discuss how to use lab equipment.
• Review how to use and read a thermometer.
• Review how to use a balance and tare weights if necessary (ensure they are familiar with grams as opposed to ounces which sometimes appear on electronic balances).
• Introduce the definition of chemical engineering and describe real-life problems that chemical engineers might try to solve. Refer to the Introduction and Motivation section as an example.

Day 1: Section 1

• Hand out Section 1 Worksheet .
• Introduce the activity, engineering connection, and strategy for the four-day lab:

Day 1 : Section 1 Worksheet (definitions and determining boiling point of various solutions).

Day 2 : Section 2 Worksheet (data analysis and determining the best line of fit on a graph for various concentrations of salt and sugar).

Day 3 and 4 : Section 3 Worksheet (design and test a solution to have a specific boiling point based on previous calculations; connect this "design criteria" to what engineers must do, that is, meet specifications).

• Discuss results (if time at the end of class, once everyone is done).

Day 2: Section 2

• Hand out Section 2 Worksheet .

Day 3: Section 3

• Hand out Section 3 Worksheet .
• Discuss how students can calculate the solute mass necessary to achieve the required boiling point.
• Have students design their solutions and begin conducting the tests.

Day 4: Section 3 (continued)

• Report results and check solutions.

boiling point: The point at which one can see a steady/continuous/rapid boiling of a liquid. This point is also characterized by a constant temperature, as long as the concentration is not being changed.

concentration: A measure of how much of some substance is contained in a mixture.

solute: The material being dissolved in a solution, typically the material present in a lesser mass, and the material that is changing state. In this activity example, the salt and sugar are the solutes.

solution: A mixture of two or more substances. In this activity, salt water solution or sugar water solution.

solvent: The liquid substance able to dissolve other substances. In this activity, water is the solvent. The solvent does not change its state when forming a solution.

At activity end, review and grade completed student worksheets to gauge their mastery of the concepts.

Safety Issues

• Students should not drink any chemicals even those labeled water or soda because contamination is always possible.
• Students should always use safe lab practices especially when working with heat. Use tongs when handling hot containers and wear lab goggles to protect eyes.

Be sure to test the boiling point of the water that will be used. A deviation of a few degrees in boiling point may exist, depending on elevation and water supply.

Ensure that the thermometers being used are accurate and precise enough to capture half-degree changes in temperature. One option is to use digital thermometers. Also, ensure that the thermometer range covers the range of boiling points possible with the solutions (~212 °F to 240 °F).

During boiling, if water vapor (steam) is escaping from the beakers, it means the concentration inside the beaker is increasing due to a loss in solvent mass. To ensure the least error, encourage students to keep beakers completely covered. If possible, use rubber bands to secure the foil lids on the beakers.

To reinforce students' understanding of concentration, provide them with two or three unknown solutions for which they must determine the concentrations. Then, as an added challenge, challenge students to develop a method to determine if the unknown is a salt or sugar solution. This would be based on the mass of the solution as long as they are given the mass of the solvent.

Ask students to create concentration curves based on other measurable properties such as density. They could then compare to see if one measurement is a better predictor for determining an unknown.

Have students perform cost analysis of their solutions for section 3, comparing their group results to other group results.

• For lower grades, minimize testing to only one solute (salt) then have students collect data as a class. During section 3, have students calculate the cost to create the required boiling point solution.
• For upper grades, have students determine the effect each solute has on the boiling point error. For example, for a one-degree boiling point increase, it requires more sugar than salt. Therefore, the same precision of weighing results in a lower error associated with the sugar solution than the salt solution. Have students come up with methods to minimize these measurement errors. In addition, have students come up with an equation to determine the boiling point of a solution containing water + salt + sugar.

Students learn how to classify materials as mixtures, elements or compounds and identify the properties of each type. The concept of separation of mixtures is also introduced since nearly every element or compound is found naturally in an impure state such as a mixture of two or more substances, and...

Contributors

Supporting program, acknowledgements.

This content was developed by the Culturally Relevant Engineering Application in Mathematics (CREAM) Program in the Engineering Education Research Center, College of Engineering and Architecture at Washington State University under National Science Foundation GK-12 grant no. DGE 0538652. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.

Last modified: November 8, 2021

Sugar Rainbow- Density Science Project

Introduction: Sugar Rainbow- Density Science Project

This is a really very simple yet beautiful experiment that barely requires just sugar/salt and water to do. It works on the principle of density. Let's begin! :)

• 10 spoons of Sugar (Salt can be used instead)
• Equal amount of water in 5 containers
• Food colouring or paint
• A pipette or dropper

Step 1: Take Equal Amount of Water in 5 Containers

take approx. an equal amount of room temperature water.

Step 2: Add a Different Colour to Each Container

Food colouring or paint can be used.

Step 3: Adding Sugar

Add spoons of sugar to the containers in the following order:

• 1st container - 0 spoons
• 2nd container - 1 spoon
• 3rd container - 2 spoons
• 4th container - 3 spoons
• 5th container - 4 spoons

And mix it till all the sugar is dissolved.

Step 4: Take a Glass Jar

Step 5: Order of Filling

the solutions should be filled in decreasing order of sugar. that is,

the colour with 4 spoons of sugar goes first, followed by 3 spoons, 2 spoons, 1 spoon and 0 spoons.

Step 6: Filling the Solutions

You have to fill up each colour one by one using the pipette or dropper very slowly , touching the side of the container (as shown in the picture) .

This is a very important step, if done otherwise, the solutions may mix together

This step requires a lot of patience! But the results are amazing too!

Step 7: The Science Behind It

it works on the principle of density.

The more the amount of sugar in water, the more is the density of water. A more dense liquid is heavier than a less dense liquid because a more dense liquid has more mass per unit volume as compared to a less dense liquid.

So, the water with less density (Less amount of sugar) will float over the water with more density (more amount of sugar) and not mix with it, which creates this beautiful rainbow effect.

Step 8: And Its All Done !

Thank you everyone for your time reading this instructable :)

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April 10, 2014

Salty Science: Floating Eggs in Water

A density demonstration from Science Buddies

By Science Buddies

Key concepts Density Mass Volume Concentration Buoyancy Water Introduction Have you ever wondered why some objects float in water and others sink? It has to do with the density of the objects compared with the density of the water surrounding them. If an object is less dense than the water around it, it will float. Because salt water is denser than freshwater, some things float more easily in the ocean—or extremely salty bodies of the water, such as the Dead Sea. You can make your own dense water by adding salt to tap water. In fact, if you add enough salt, you can make the water so dense that an egg will actually float in it! Explore how this works in this science activity.   Background If you put an egg in a cup of tap water, it will sink to the bottom. Why is this? Because the density of the egg is higher than the density of tap water, so it sinks. Density is the mass of a material per unit volume. For example, the density of freshwater under standard conditions is approximately one gram per cubic centimeter.   But, if you add enough salt to the water, the egg will actually float back up to the surface! Adding salt to the water increases the density of the solution because the salt increases the mass without changing the volume very much.   When enough salt is added to the water, the saltwater solution's density becomes higher than the egg's, so the egg will then float! The ability of something, like the egg, to float in water or some other liquid is known as buoyancy. But just how much salt is needed to make an egg float? In this science activity you'll figure that out by making solutions with varying concentrations of salt in them.   Materials

Measuring cup

Large container, such as a large bowl or cooking pot (It must be able to hold at least three cups.)

One half cup of table salt

Five cups that hold at least 16 ounces each

Permanent marker (if you are using plastic cups) or masking tape and a pen (to label nondisposable cups)

Three spoons for mixing salty solutions

Soup spoon for egg transfers

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  Preparation

Take the egg out of the refrigerator and allow it to warm to room temperature. Be sure to always wash your hands after handling uncooked eggs because they may carry salmonella.

Pour one and one half cups of water into your large container.

Add one half cup of salt to the large container and stir to dissolve some of the salt (it will not all dissolve yet).

Add one more cup of water to the large container (making two and one half cups total) and stir to dissolve the remaining salt. The salt should be completely dissolved before you go on to the next step. It may take several (five to 10) minutes of stirring, so you may need to be patient. Why do you think it's important to start out with a solution that has such a high concentration of salt?

Arrange the five cups on a surface, going in a line from left to right. Label the cups 1 to 5. If you are using plastic cups, you can use a permanent marker to label them. If you are using nondisposable cups, you can use masking tape and a pen to label them.

Add three quarters cup of the salty solution you prepared to cup 1.

Add three quarters cup of plain tap water to cups 2 through 5. (Cup 5 will be plain tap water.)

Add three quarters cup of the salty solution you prepared to cup 2 and mix it. What is the salt concentration in cup two compared with cup one?

Add three quarters cup of the salt solution from cup 2 to cup 3 and mix it. What is the salt concentration in cup 3 compared with cups 1 and 2?

Add three quarters cup of the salt solution from cup 3 to cup 4 and mix it. What is the salt concentration in cup 4 compared with the other cups?

Use a soup spoon to place an egg in cup 5. Does the egg float?

Use the spoon to take the egg out and place it in cup 4. Does the egg float?

Repeat this process with cups 3, 2 and then 1. In which cup does the egg first float? If the egg floated in more than one cup, did you notice any difference in how it floated? What does this tell you about the density of the egg?

Extra: In this science activity you figured out, within a factor of two, how much salt it takes to float an egg. You could narrow down the range further by testing additional saltwater solutions to try and determine the egg’s density. To do this, start your solution with the salt concentration in which the egg first floated and make a new dilution series, as you did before. Now in which cup does the egg first float? What does this tell you about the density of the egg?

Extra: Repeat this activity using several more eggs, possibly both hard-boiled and uncooked eggs. Do you get the same results with other eggs or is there some variation between different eggs? For testing hard-boiled versus raw eggs, you should test the same egg, first raw and then after hard-boiling it to investigate any differences.

Extra: Find out how much salt there is in seawater. From the results of your activity, do you think an egg would float or sink in seawater?

 [break] Observations and results Did the egg float in cup 1 and 2, but not in cups 3, 4 or 5?   You likely saw that the egg floated best in cup 1, floated a little less in cup 2 (but part of it was above the surface) and did not float in the other cups. Cup 1 had the undiluted salty solution that you originally prepared, which was one half cup of salt in two and one half cups water total. The concentrations of the salt solutions in cups 2 to 4 were halved as you increased in cup number; for example, the concentration of the salt in cup 2 was half that of cup 1, and the concentration of the salt in cup 3 was half again of cup 2. (Cup 5 had plain tap water.) The egg should have sunk in cups 3, 4 and 5 because the density of the egg was higher than the density of the solutions (or plain tap water) in those cups. Cups 1 and 2 had more salt in them than the other cups (with cup 1 having the most salt), which means these solutions were denser. The egg should have floated (with part of it above the water surface) in these two cups because the solutions were denser than the egg. The actual density of the egg is in between the density of the solution in cup 3 and that in cup 2.   More to explore What Is Density? , from Charles E. Ophardt, Elmhurst College Why Is the Ocean Salty? , from Herbert Swenson, U.S. Geological Survey Publication Fun, Science Activities for You and Your Family , from Science Buddies How Salty Does the Sea Have to Be for an Egg to Float? , from Science Buddies

This activity brought to you in partnership with Science Buddies

Salt or Sugar: Which Dissolves Faster in Different Liquids?

Solutions are nothing more than mixtures of different compounds or elements. You encounter solutions every day without even realizing it.

Even the air you breathe-which contains water-is a solution of a liquid and a gas. If you drank a soda today, you actually drank of solution of a gas dissolved in flavored water. If you're wearing a bracelet made of sterling silver, you're wearing a solution of two metals.

In this experiment, you'll be working with a liquid solution, which is one of three types of solutions. The other types are gaseous solutions and solid solutions.

So What Seems to Be the Problem?

Mixing a liquid in a gas makes another type of solution, called a gaseous solution. An example of this type of solution is humidity. Humidity is water (a liquid) dissolved in air (a gas).

In a solid solution , such as sterling silver, copper that has been heated at high temperatures is mixed with silver that also has been heated until it melts. The copper is the solute , which is the substance that will dissolve into the solvent . The silver is the solvent.

The type of solution is determined by the state of matter of the solvent. If the substance doing the dissolving is a liquid, the solution is called a liquid solution. If the solvent is a gas, the solution is called a gaseous solution. And you guessed right: A solid solvent will form a solid solution.

There are a few factors that generally increase the amount of solute that can be dissolved. If you want to dissolve more sugar in the same amount of water, for instance, you could heat the water. You also could grind the sugar into smaller particles to increase its surface area, or you could stir the mixture.

In the years that you've been using salt and sugar on your foods, you've probably noticed that each piece of salt-which actually is a crystal-is a little smaller than each piece of sugar, which also is a crystal.

The problem you'll be attempting to solve in this experiment is whether sugar or salt dissolves faster when mixed into various liquids. Does the size of the pieces affect how quickly they mix with the liquid?

When you dissolve sugar or salt in a liquid-say, water-what happens is that the sugar molecules move to fit themselves between the molecules of water within a glass or beaker. The illustration below shows how the different molecules are arranged in the container.

In your experiment, you'll see how salt and sugar molecules move within different liquids and dissolve at different rates.

The title of this section, "Salt or Sugar: Which Dissolves Faster in Different Liquids?" could serve as your project title, if you want. You also could consider one of the following titles for your project:

• The Great Salt vs. Sugar Dissolving Contest
• Using Salt and Sugar to Explore How Substances Dissolve

Whatever name you choose is fine. Let's take a minute now to consider why this project is a valuable use of your time.

What's the Point?

And when the excessive solute has been dissolved by heating the solution, it's said to be supersaturated .

The point of this experiment, in addition to learning whether salt or sugar dissolves faster in various liquids, is to learn how molecules interact in a solution.

As you saw in the preceding illustration, the water molecules take up most of the room in the container. But there is still some available space in which the sugar or salt molecules can fit. Through your experiment, you'll learn how fast the sugar molecules fit into those spaces, as compared to the salt particles.

Knowing this will help you better understand the process that occurs as a substance dissolves.

The control in your experiment will be water. The other liquids in which you dissolve salt and sugar will be the variables.

Remember when you conduct your experiment that it's very important that the liquids you use are all the same temperature. You already learned that sugar dissolves faster in a warm liquid than in a cool one, so you know it wouldn't be an accurate experiment if some of the liquids you use are warm and some are cold. The temperature of the liquid would become a variable.

Therefore, all the liquids you use-including water-should be at room temperature. If you normally keep them in the fridge, be sure to allow them to sit out on the counter overnight until they are all the same temperature.

To give you a little more flexibility when you conduct the experiment, you may choose the liquids in which you'll dissolve sugar and salt. There's no point in having to go out and buy additional liquids if you've already got what you need.

Just make sure you choose liquids that are different from each other in taste, color, odor, and purpose. You'll also need to select those that allow you to observe the salt and sugar as it dissolves. If you use milk or orange juice, for example, you won't be able to watch the salt and sugar dissolve. Some suggestions for liquids to consider are:

• White vinegar
• Glass cleaner (such as Windex)
• Tea or iced tea (each at room temperature)
• Apple juice
• Rubbing alcohol

All of these are commonly found around the house, perhaps saving you a trip to the store.

What Do You Think Will Happen?

Now that you know how solutions are formed and some of the factors that will affect the speed at which the sugar and salt you'll be using will dissolve, you should be able to make a good guess as to which one will dissolve faster.

While you won't know until after your experiment if properties of the different liquids you choose will affect the rate at which the salt and sugar dissolve, you do know that salt crystals are generally smaller than sugar crystals. And you know that the temperature of the liquids will not be a factor in your experiment.

Just try to use your past experiences, the information you've read earlier in this section, and your common sense to come up with a sound hypothesis.

Remember that your hypothesis must be stated as an objective sentence, not a question. So go ahead and -make your guess as to whether the salt or sugar will dissolve faster, and let's get started with the experiment.

Materials You'll Need for This Project

Some liquids suggested for use in this experiment are white vinegar, club soda, ginger ale, glass cleaner, rubbing alcohol, apple juice, lemonade, and tea. If you want to substitute another liquid for one or more of the ones suggested, that's fine. Just be sure that all liquids are clear and at room temperature.

The amounts of materials listed below are enough for you to conduct the experiment three times with each liquid. You'll need:

• 12 clear, plastic cups (10 ounce [300 ml])
• One permanent marker
• One (1 teaspoon) (5.0 ml) measuring spoon
• One ( 1 2 teaspoon) (2.5 ml) measuring spoon
• One (1 cup) (240 ml) measuring cup
• 8 teaspoons (40 ml) salt, divided in 16 ( 1 2 teaspoon) portions
• 8 teaspoons (40 ml) sugar, divided in 16 ( 1 2 teaspoon) portions
• 48 ounces (1,440 ml) water at room temperature
• 24 ounces (720 ml) each of five different, clear liquids, all at room temperature
• One clock or watch with a second hand
• One clear plastic cup containing eight fluid ounces (240 ml) water at room temperature

Remember to make sure that all liquids are at room temperature.

Conducting Your Experiment

When you've gathered all your materials, you'll be ready to begin your experiment. Just follow these steps:

• Using the permanent marker, write "salt" on six of the plastic cups, and "sugar" on the other six.
• Place 1 / 2 teaspoon (2.5 ml) of salt into each of the six cups labeled "salt."
• Place 1 / 2 teaspoon (2.5 ml) of sugar into each of the six cups labeled "sugar."
• Add 8 ounces (240 ml) water to one cup containing salt, and one cup containing sugar. Immediately record the time at which the water was added on a data chart similar to the one shown in the next section, "Keeping Track of Your Experiment."
• Observe the solutes (salt and sugar) dissolving in the solvent (water). Record on the data chart the time at which it appears to you that each solute has completely dissolved. These times will probably not be the same.
• Calculate the elapsed time during which the dissolving occurred. Take the time at which the water was added to the cups and the dissolving started, and subtract it from the time the dissolving ended. This gives you the total minutes it took for the salt and sugar to completely dissolve in the liquid.
• Repeat steps 4 through 6, using each different liquid instead of the water.
• Wash, rinse, and thoroughly dry each of the 12 cups.
• Repeat steps 2 through 8 two more times, for a total of three trials for each of the six liquids.
• Calculate an average dissolving time for the salt and the sugar in each of the six liquids.

Remember that to find the average time it took for the salt and sugar to dissolve in each liquid, you add the three times recorded for each one, then divide them by three. The number you get when you divide the times is the average time.

Keeping Track of Your Experiment

Charts such as the following one can be used to record information for each solvent. Simply change the names of the solvents in the heading.

Be sure to record the times as you go along. Don't depend on your memory to write them down later. You're going to have a lot of numbers by the time you finish your experiment.

Putting It All Together

What did you notice about the rates at which the salt and the sugar dissolved? Did you prove your hypothesis to be correct? Or incorrect? Could you detect any type of pattern as you added the salt and sugar to the various liquids? Was it obvious that the salt dissolved better and faster in some liquids compared to the sugar? Can you think of any reasons for which that might have occurred?

Do you think that the chemical natures of the solute and the solvent affected the dissolving rates? Use the information you gathered when you researched your topic to help you answer these questions.

The more you know about your project, the better able you'll be to analyze your data correctly and come up with a sound conclusion.

Further Investigation

As mentioned earlier, the factors affecting the solubility of solid solutes are:

• Increasing or decreasing the temperature of the solvent
• Increasing the surface area of the solute

If you wanted to take this project a step or two further, you could design an experiment that would test one-or perhaps all-of these variables.

You could easily compare the rate at which sugar cubes dissolve in liquid with the dissolving rate of granulated sugar.

Or you could use the same solute-say, sugar-and test whether stirring the solution caused it to dissolve faster. Heating and cooling the solvent as you add the same solute also would be a possibility for further experimentation.

If you're curious and willing to experiment, you probably can think of many variations for this project. And, because the experiment calls for only common, inexpensive materials, you should be able to experiment to your heart's content.

Easy and fun hands-on chemistry experiment

Students learn about molecules and solutions with this hands-on science activity, performing a series of experiments to determine whether sugar or salt dissolves faster when mixed into various liquids.

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Science project, what makes ice melt faster.

Grade Level: Middle School; Type: Chemistry

This experiment explores how salt and sugar affect the melting rate of ice in water.

Research Questions:

• Does adding salt to ice and water slow down, speed up, or not change the rate the ice melts in the water?
• Is salt the only substance to have this effect? What about sugar?

Knowing how to speed up the melting rate of ice is very important information for anyone who needs to de-ice roads or driveways after a winter storm. While it seems simple, adding salt to ice water actually activates two complex, and contradictory, chemical reactions. The salt disrupts the equilibrium of water and ice, slowing down the amount of water freezing into ice and speeding up the amount of ice melting into water. However, because of this disruption, salt lowers the temperature of the water, making the overall melting rate decrease. Which reaction will win out? We’ll also test the effect of sugar on ice.

• Three cups of equal size, one labeled “control,” one labeled “salt” and one labeled “sugar”
• Notebook and pen

Experimental Procedure:

• Fill each cup with water.
• Add the same amount of ice to each (about four to five cubes, depending on size of cups).
• In the cup labeled “salt,” sprinkle on a tablespoon of salt. Do not stir.
• Immediately sprinkle a tablespoon of sugar into the cup labeled “sugar.” Do not stir.
• Start the stopwatch.
• Note down the amount of time it takes for the ice to completely melt into water for each cup.
• Clean out the cups and repeat experiment three times or more, always keeping careful notes.
• Analyze this data. Figure out the average time it takes for ice to melt in plain water, water with salt added and water with sugar added.
• For further evaluation, try using different amounts of salt. Feel free to experiment with other substances as well, like rubbing alcohol or sand.

Terms and Concepts: molecular thermodynamics, equilibrium, freezing point, melting point, hydrogen bonds

References:

• http://www.ehow.com/info_8526760_salt-affect-ice-water.html
• http://antoine.frostburg.edu/chem/senese/101/solutions/faq/why-salt-melts-ice.shtml
• http://antoine.frostburg.edu/chem/senese/101/solutions/faq/why-salt-cools-icewater.shtml

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• Why We’re Unique

Salt and the boiling temperature of water

Introduction: (initial observation).

At home hot water is used for cooking and heating systems such as hot water radiators. In laboratories hot water is used in water baths. Hot water has many industrial applications as well.

One problem with water is that it never gets hotter than 100º Celsius. Any additional heat will only cause more evaporation. Being able to control or modify the boiling point of water may be helpful for any applications requiring heat transfer.

In this project you will study the effect of table salt on the boiling temperature of water. Report your results in a table and draw a graph to visually display your results.

If you have any questions, click on the “Ask Question” button at the top of this page to send me your questions. I may respond by email, but often I update this page with the information that you need.

You will also need to know:

• How to select a project?
• What are variables (Dependent, Independent, Control)?
• What is a control experiment?
• How can I do analysis and discussion?
• Do I need a graphs or a chart?
• What is an abstract? How to write it?
• Samples of display boards   
• How to write a report?

Project Advisor

Information Gathering:

Find out about boiling and boiling point point. Read books, magazines or ask professionals who might know in order to learn about the effect of salt on the boiling point of water. Keep track of where you got your information from.

matter : anything that occupies space and has mass.

mass : the quantity of matter contained by an object. Mass is measured in terms of the force required to change the speed or direction of its movement.

liquid : the state in which matter takes the shape of its container, assumes a horizontal upper surface, and has a fairly definite volume.

boiling point : the temperature at which the vapor pressure of a liquid equals the pressure of the gas above it.

temperature : measure of the hotness or coldness of a body.

pressure : force exerted on a unit area. The SI unit of pressure is the Pascal (Pa).

gas : the state in which matter has neither definite volume nor shape.

boiling -point elevation: the elevation of the boiling point of a liquid by addition of a solute.

Effect of air pressure

A liquid boils when its vapor pressure becomes equal to atmospheric pressure. Low atmospheric pressure causes the boiling point to go down; high pressure drives it up. Atmospheric pressure varies a bit from day to day, depending on the weather, and it varies from place to place, depending on the altitude.

Other related links:

• Boiling Point
• Boiling point elevation
• Boiling temperature of water solutions

Question/ Purpose:

What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.

The purpose of this project is to determine the effect of salt on the boiling point of water.

Identify Variables:

When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.

• The independent variable (also known as manipulated variable) is the amount of salt.
• Dependent variable (also known as responding variable) is the boiling point of water.
• Controlled variables are the air temperature and pressure. Perform all your experiments in the same day while the air pressure and temperature will not be subject to noticeable changes.

Hypothesis:

Based on your gathered information, make an educated guess about the effect of salt on boiling point of water.

Following are two sample hypothesis:

Sample hypothesis 1:

I hypothesize that salt will reduce the boiling point of water. My hypothesis is based on my information that salt reduce the freezing point of water and it is used as an anti freeze in winter.

Sample hypothesis 2:

I hypothesize that salt will increase the boiling point of water. My hypothesis is based on my information that salt does not boil as easy as water, so when mixed with water it may make it hard for water to boil as well.

Experiment Design:

Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”

Introduction : In this experiment you will test the effect of table salt (sodium chloride) on the boiling point of water. You may repeat this experiment with other solutes such as sugar, Epsom salt (Magnesium sulfate) and Salt cake (Sodium sulfate). Experiment involve preparing salt-water solutions with different amounts of salt; heat them to the boiling temperature and then measure and record the temperature while the solution is boiling.

• Fill up a glass beaker or a small pot with 100 ml distilled water.
• Place a thermometer in the water several centimeters from the bottom of the pot. Make sure you are using a thermometer with at least one degree markings to insure accurate measurements.
• Begin to heat the water. Take temperature readings every 10 seconds.
• Continue reading the temperature until it remains constant for at least four measurements. This is the boiling point.
• Repeat the steps 1 to 4; however, each time add a different amount of salt to the water. Suggested amounts of salt are 5, 10, 15, 20 and 25 grams as shown in the following table.

Your results table may look like this:

• Use tap water or drinking water if you don’t have access to the distilled water
• If your pot or beaker are big and you need to do your experiment with more water, increase the amount of salt at the same ratio.
• C = Celsius Temperature Scale (Centigrade)
• F = Fahrenheit
• If you don’t have a scale to weight 5 grams salt, use one small tea spoon. That will hold approximately 5 grams of salt.
• The first experiment with pure water is also the control for your other experiments.
• 102ºC and 106ºC in the above table are possible answers reported by other students. Please note that they may be wrong or inaccurate!

Make a bar graph:

For each of the six solutions that you test make a vertical bar (so your graph will have 6 vertical bars). The height of each bar will represent the boiling temperature of one specific solution. The name of the bar will be the amount of salt added.

The bar graph in the right is for a similar experiment with only 3 different solutions. 0 is for no salt, 1 is for 1 table spoon and 2 is for 2 table spoon salt in one quart of water.

Materials and Equipment:

• Thermometer* (available at science suppliers),
• Glass beakers or metal pots,
• Electric stove (hotplate)

* Glass and dial thermometers shown above are available at MiniScience.com and klk.com. Either of the two models may be used for freezing temperatures. Dial thermometers last longer; however, glass thermometers are more accurate.

Results of Experiment (Observation):

The above table will be completed and used as the result of your experiment. You may also write in a paragraph or two the result. What you write may be an answer to the following questions:

1. What was the highest temperature that the salt water reached?

2. At what temperature does the pure water boil?

If the thermometer extends beyond the outside of the pot it reads a higher temperature. Heat from the stove burner makes the thermometer read higher. Keep the thermometer over the pot when making temperature measurements.

Calculations:

No calculation is required

Summary of Results:

Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.

It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.

Conclusion:

Using the trends in your experimental data and your experimental observations, try to describe the effect of salt on freezing point of water. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.

Related Questions & Answers:

What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.

Possible Errors:

If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.

If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.

References:

Visit your local library and find books about salt, water, general chemistry, physical chemistry or chemical physics. Look for chapters that discuss changes in physical properties of a substance when mixed with other substances.

List the books and the online resources that you use in this part of your report.

It is always important for students, parents and teachers to know a good source for science related equipment and supplies they need for their science activities. Please note that many online stores for science supplies are managed by MiniScience.

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Science Project

Floating Egg Science Experiment ( Using Salt, Sugar & Saline Water)

• December 10, 2020
• 10 Minute Science , 5-6 Year Olds , 7-9 Year Olds , Physics , Rainy Day Science

Hello everyone! Today we have come up with simple ‘ Floating Egg Science Experiment with a twist’ that can be done within 5-10 minutes.

My kids call it as a pre-breakfast activity. This is an easy and funny experiment to teach density for kids .

We know that some things float in the water and some others not. Do u know why the things sink in the water!? Let us learn something about floating science using eggs.

Floating Egg Experiment

This activity is a cool way to learn the concept – density! We are going to perform the experiment with four different liquids to understand the science behind floating objects in water.

We commonly see that eggs sink when we put in the water. What is the reason behind this!? Does egg sinks the same way when dropped in other liquids? We will perform a simple activity to learn the science behind it.

Try our 20+ Egg Science Experiments

Materials Required for the Activity

• Saline water (You can find saline water in any of the local pharmacies)
• Four glass jars (Either you take glass jars or beakers, make sure they are tall and wide enough to drop an egg)
• Four Raw Eggs (Ensure the eggs are not broken or given any crack to avoid the unnecessary mess with the leaky eggs during experiment)
• Fill one tall drinking glass or glass beaker about ¾ full of water.

• In the same way, fill the other glass with salt water. To prepare salt water, put 1-2 cups of salt in 500ml of water. Stir it with the spoon. That’s it. You are done with making salt water.

• Now it is second drinking glass turn! Fill it with sugar water. Prepare the sugar water same like how we made salt water in previous step.

• Saline water! Yes, we are using saline water as well to observe the floating science with eggs. Fill the fourth glass beaker with saline water.

• Finally, we have arrived to the kid’s favourite step i.e. dropping egg into the tall drinking glasses.

My younger daughter is eagerly waiting for my instructions to drop the egg in the liquids. When I said so, she carefully dropped the raw eggs into the four glasses filled with four different liquids each.

Ask your kids to observe the results that in which liquid the dropped eggs are floating or sinking.

On the initial test, we only had egg floating in the salt water. The sugar water was not dense enough to make the egg float. So we tried to add more sugar to the already prepared sugar solution.

Finally we made the egg float in the sugar water as the water is now more dense due to the added sugar.

How Does the Floating Egg Science Experiment Work?

Let us discuss the results of our experiment. The raw egg dropped in the tap water sinks immediately as soon as it is dropped. On the other hand the egg in the salt water floats.

We observe the same results with the sugar water as well. The raw egg floats nicely in sugar water as well.

How about our egg in the saline water? The egg didn’t float surprisingly in the saline water.

Now let us discuss on what made the eggs in salt & sugar water float and why the egg in normal tap water and saline water sink!?

Science behind floating egg

The egg in the glass of regular tap water sinks to the bottom because the density of egg is more compared to density of water.

Why the egg in salt water floats? When the salt is added to the water, it increases the density of the water and hence the density of the egg slowly becomes lesser than the salt water.

You are dissolving the more the salt into the water means you are increasing the density of water. The denser the liquid is the easier for the object in the water to float.

The same formula applies to the sugar water. The density of sugar water is more than the density of egg.

On the other hand, saline water is made of salt and water. However, the density of the saline water that we used seems to be lower than than egg. Thus it floated in the sugar water and sinked in the saline water.

Density is a concept dealing with how closely a substance is packed to be together.

We will compare this concept with our daily life things. For example: consider we have two bowls one is filled with salad and the other is with rice.

Both are of taken in same quantity but we feel the salad bowl is lighter than the rice bowl because the ingredients are packed tightly in the rice bowl than the salad of lettuce and vegetables which are very light in nature.

In the same way, the molecules in the salt, sugar, and saline water are packed more closely and makes the salt, sugar, and saline water denser than the water where the molecules are packed lighter thus making it less denser.

Even the egg has some density but less than the salt water and hence the egg floats in salt, sugar, and saline water.

So, when you go to swimming pool or beach or ocean, observe that you will float easily and lightly compared to salt water. The denser the liquid, the easier you will float! Amazing right!?

Experiment Extensions

Try different liquids and different substances to dissolve in the water in order to make an egg float.

Try these Density Science Experiments :

9 Layer Density Tower

Hot & Cold Water Experiment

DIY Sugar Density Rainbow

Oil, Food Color & Water – Fireworks

How to make Lava Lamp

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Experiments With Salt Melting Ice

Science Projects and Research With Salt, Sugar, Water and Ice Cubes

Teachers interested in using salt and ice experiments in the classroom can incorporate a range of theories and methods into lessons. Discuss the properties of salt and its effect on water, the influences on melting ice, or the creation of ice crystals in the winter. Using salt and ice to explore melting points allows students to develop an understanding of substances and their chemical reactions.

How can salt lower the freezing point of water?

This experiment involves students testing the properties and effects of salt on ice and water. Students need 2 cups of water, salt, ice cubes and access to a freezer. First put a tablespoon of salt into one of the cups of water, and place both cups into the freezer. Check each cup every 10 minutes and take a guess as to which cup's water will freeze first. Next, take two ice cubes out of the freezer and put them on a plate. Sprinkle some some salt on one of the ice cubes. Observe and record which ice cube melts the fastest. These two experiments allow students to determine that salt lowers the freezing point of water. Students can infer that salt water can still freeze, but the temperature must be colder than fresh water.

Thread the Ice

Demonstrate the properties of solids and liquids by using an experiment with water and ice. Students need an ice cube, a bowl, some thread and salt. Place the ice cube in the bowl and put the thread across the ice. Sprinkle some salt along the thread and on to the ice cube. Wait for two minutes, and carefully pull the ends of the thread. The thread is now frozen to the ice. The teacher can explain that liquid water has molecules that move around, while the molecules in the solid ice are fixed and do not move. Describe the process of ice melting in terms of the exchange of molecules due to temperature changes. The salt is diluted by the water that has melted off the ice, allowing the ice to capture some of the molecules of water which causes the ice to freeze around the thread.

Salt vs. Sugar: Melting Ice

Compare the effects of salt and sugar on water and ice. Students observe the properties of ice, and that salt speeds up the rate of ice melting compared to sugar or nothing. Students need three zip-lock bags, a teaspoon, ice cubes, salt, sugar and a plastic sheet to cover the work area. First label each zip-lock bag with either control, salt or sugar. Place an ice cube in each of the bags. Measure a teaspoon of salt and place it in the bag labeled salt. Measure a teaspoon of sugar and sprinkle it in the bag labeled sugar. Seal the bags and observe the three ice cubes in the different conditions. Students can infer which ice cube will melt the fastest by watching the transformation of each ice cube.

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Science projects and research with salt, sugar, water..., second-grade science lessons using salt, freezing point explanation for kids, science projects on what liquid freezes faster, sugar dissolves in water faster than salt science projects, experiments with salt and sugar ice cubes, how to perform science experiments using salt, the effects of salt on ice cubes, one day science fair project ideas, density experiments for kids, how to prevent an ice cube from melting quickly, high school science experiments with plants, preschool blubber experiment, osmosis experiments with potatoes for kids, substances that affect the rate of melting ice, osmosis science activities for kids, osmosis experiments with gummy bears, food coloring & science projects, how does a sugar crystal grow, 5th grade solubility experiment.

• CSIRO: Salt vs. Ice
• Project Labs: Ice cubes and salt

About the Author

Amanda Wehner is a primary teacher with a Master of Teaching degree. Her dissertation focused on researching the current crisis amongst boys and literacy skills. Before completing her research, Wehner had received an undergraduate degree with a double major in psychology and biology.

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