salt water density experiment worksheet

Salt Water Density Experiment

Introduction: Salt Water Density Experiment

Step 1: Materials

Step 2: Procedure

Step 3: Additional Ideas and Resources

Extension/Modification Ideas:

• Use a triple beam balance of electronic scale to teach or practice that skill
• Use hot and cold water instead.
• Compare salt and fresh water and connect with the environment.
• Have older students teach this to younger students.
• Use other liquids to make density columns. (Water, oil, alcohol, etc.)
• Make a much larger one as part of a science night.
• Let students try making different density salt solutions and try to figure out which ones work the best and how that relates to density.

Other Density Demos:

• Egg in salt water or tap water
• Ice in water or rubbing alcohol

Attachment: I attached a Word document that is a template for a guided lab report that you feel free to modify and use. Other Ideas and Resources: These are just some ideas and alternate extensions. Some additional references will many different versions of this same idea: DENSITY: SALTWATER COLUMN LAB TEACHER PREPARATION Explains a different way to prepare solutions and some "discussion" questions as a worksheet for students Liquid Rainbow Written from the standpoint of ocean science for elementary school. Contains a lot of "teacher lingo" (e.g. key concepts, big idea, objectives, etc.) GEMS: Discovering Density book This book costs $18, but I think is where I first saw the idea for this lab. The handouts are free online in Spanish. So that might make this a cool activity to do with students learning Spanish too! Steve Spangler 7-Layer Density Column This link provides a video showing a different density experiment with different types of liquids to see how their relative densities are different. They do use the word "heavier" instead of density. He uses a slightly different way of layering. NOAA Lesson Plan: Hot, Cold, Fresh and Salty Another Earth Science/Oceans connection. This lesson plan gives ideas about having students compare hot and cold water and fresh and salty water. These are extensions that would be great to add to a simpler lesson like the one I posted.

Step 4: Real World Connection

In research labs, human blood is carefully pipetted to form a layer on top of a substance called Ficoll-Paque (made by GE). When this tube is centrifuged, the red blood cells (the most dense) go to the bottom, the Ficoll is (the next most dense), then the white blood cells, and finally the plasma (the least dense). Labs use this technique to isolate different parts of the blood. For instance, if you want to isolate the white blood cells, you can remove the plasma layer (yellow) and then gently extract the thin cloudy white layer that contains the white blood cells. Wikipedia's Ficoll-Paque Article This page describes the basics of Ficoll Ficoll-Paque PLUS Manufacturer's Description A short paragraph from the manufactures that uses the word density multiple times Ficoll-Paque Instructional Video This video shows the layering of blood on top of the Ficoll very slowly and gently and the final layers that form

Step 5: Graphic Organizer Word Document

Someone let me know the Word document does not open currently. I tried uploading another version but it also says forbidden. Message me and I can try to send it to you.

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Salt Water Density Experiment

Can you make a fresh egg float in water? Will an egg float or sink in salt water? What is density? What is buoyancy? Answer these questions with this easy floating egg salt water experiment. Check out all our classic science experiments for more great ideas!

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

• 2 Tall glasses big enough to hold an egg

Floating Egg 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!

Science Information

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 excellent 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 salt comes from the rocks on the land that have been broken down by erosion and are carried 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? 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!

Turn It Into A Floating Egg Science Fair Project

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

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

To turn the floating egg experiment into a science fair project using the scientific method, start by posing a clear question. For example, “How does the salt concentration in water affect an egg’s buoyancy?” Formulate a hypothesis predicting the outcome: “The higher the salt concentration, the more likely the egg will float.”

Design the experiment by preparing several solutions with varying amounts of salt dissolved in water ( variables ), then placing an egg in each solution and observing whether it floats or sinks.

Collect and record data on the egg’s buoyancy in each solution, noting the specific salt concentrations. Analyze the results to see if they support your hypothesis. Finally, present your findings, discussing how the salt concentration affects the egg’s buoyancy and reflecting on any potential improvements or further questions during the experiment.

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?

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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Sink or Float: Density of Salt Water

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Today I want to show you a Sink or Float Salt Water Density activity we did.  I have been wanting to do this activity for a long time and I’m glad we finally got around to it!

We experimented with the salinity of water and how it affects items sinking or floating.  We did this on the density of water based on its salt content by using fresh water, and also water with the approximate salt content in the ocean, the Great Salt Lake, the Dead Sea (bordering Israel and Jordan).

I have spent a lot of time around different bodies of salt water in my life. I grew up in Florida right by the ocean and spent many many days swimming in the ocean there.

I also had the opportunity to do a semester abroad in Israel and swam in the Dead Sea while there.

Now, I live near the Great Salt Lake and have had the opportunity to visit it with my children.  The last time we visited the Salt Lake as a family, I started thinking about trying this sink or float experiment at home with my kids.

I remember swimming in the Dead Sea. The amount of salt in the water makes your skin sting a bit when you go in.  It is nearly impossible to not float due to the high density of the water. It is a strange feeling to just float so easily in water with very little effort.  There is a similar feeling in the Salt Lake.

Different amounts of salt in the water will create different densities. Denser water will create greater buoyancy, meaning things will float more. We decided to simulate this by trying to recreate water with the same amount of salt as each of these bodies of water.

Since we had some background knowledge to this already, we knew our predictions would likely be correct. The more salt you add to water, the more dense it will be, and thus the more likely it will be that items will float in it.

How to Do the Sink or Float: Density of Salt Water Experiment

Supplies We Used:

Quart sized glass jars, wide mouth

Measuring cup and teaspoon

Various household objects

In deciding how much salt we put into the water, we based it on the percentage of salt in each body of water. I used a food scale to measure it in grams. This makes it a little easier anymore accurate.

Our control was the fresh tap water. We filled one jar with 3 cups or 720 g. of regular water and tested what would float in it. We used a few different items to compare. We put the same amount of water in each jar with varying amounts of salt percentages.

Quantity of Salt in Ocean Water:

The next jar was our ocean water. Salty ocean water is 3.5% salt. So in a jar with 3 cups or 720 g. of water that would equal 25.2 grams of salt. A teaspoon was approximately 6.5 g. of salt or 3 3/4 tsp. salt.

Quantity of Salt in the Great Salt Lake

For our third jar of water, we created water similar to the salinity of the water in the Great Salt Lake. This one is tricky because the salt levels fluctuate based on the water levels of the lake and also the location in the lake. Some areas have a higher salt content than others. I decided to go with sort of a middle, average range of 15%. That equaled 108 grams of salt which is a little more than 1/3 c of salt in 3 c. of water.

Quantity of Salt in the Dead Sea

The fourth jar of water represented the Dead Sea. The water in the Dead Sea is one of the saltiest bodies of water on the earth’s surface.  There is eight times more salt in Dead sea than ocean 36% salt!  At 36% salt that equals 259.2 grams of salt (about 3/4 c.) of salt in the 720 g. (3 c.) of water.

Saltiest Body of Water: Gaet’ale Pond

The Dead Sea is not the saltiest body of water on earth. Gaet’ale Pond in Ethiopia is 43% salt, but you can’t swim in this one!  It’s typically over 120 degrees Fahrenheit and emits toxic gases.  We did not test out the density of this one, but it is a fun fact to teach!

Will it Sink or Float?

Once the jars have both the salt and water, stir them with a spoon until the salt is dissolved as much as possible. It may get a little messy, so if you are concerned about mess, do this experiment outside, over a sink or in a small tub to catch the spills.

Now you can test out the density of each of the jars of water by seeing what things will sink or float in each jar.

Objects to Try for the Sink or Float Experiment

We tested out each of the jars of water with several common household items.  You can try anything, but here are some ideas:

• wooden blocks
• hard-boiled egg vs. a raw egg
• cherry tomatoes
• plums, apples, oranges, grapes
• highlighter pens (pencils and crayons would work well)
• ping pong balls or bouncy balls, aluminum foil rolled into a tight ball
• small toys- like lego, or army men, small toy cars
• small objects like a coin, a paper clip, dry pasta, eraser, bottle cap, buttons, coins

Try a variety of dense objects and buoyant objects so you can get a better idea of how they work.

It was really fun to make a prediction of each object and then see which guesses were correct. Sometimes we were surprised by the outcome. It was also surprising to see how much more things would float in the the saltiest water.

Our predictions that overall liquids with more salt will have a higher density and fresh water will have a low density.

Sometimes an object would sink in the fresh water, but float in all of the salt water jars, no matter the amount of salt. Sometimes we could see that the object would sit higher or lower at the top of the water.

We really enjoyed this experiment and hope you will, too!

See More Water Experiments: 25 Water Science Experiments and Activities!

Also check out this  Density Experiment for Kids where we tested the density with different liquids and substances including corn syrup, gel, and more!

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

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Salt Water Density Experiment

How does food coloring react to salt & fresh water.

We love experiments that are no fuss and easy! Paired with our FREE observation lab sheet, how can you go wrong! Your students get to predict what they think will happen, make observations, and then conclude why. This experiment uses simple kitchen items to mesmerize your students. We use this Salt Water Density Experiment while investigating our Earth’s Water Unit since it is an effective at displaying the difference in density between salt and fresh water.

*Don’t miss our Floating Egg Experiment with FREE lab sheets that also investigates the difference in density between fresh and salt water. Wait… there’s more! Discover how the freezing point of salt water and fresh water differ in this experiment, “Does Fresh or Salt water freeze faster?”

As a Christian Book and Amazon affiliate, we may earn commissions from qualifying purchases. Thank you for your support. As always, we only recommend items that we truly feel will benefit your homeschooling experience. We appreciate it.

Important Terms and Facts to Introduce

Before conducting the experiment, there are a few things you should cover with your students to create a meaningful learning experience. First, spend time talking about the terms below. We discuss the meaning of salinity and density amongst other terms.

– Density is the amount of mass in a given volume.

– Salt is also called Sodium Chloride.

– Salinity  describes the amount of salt dissolved in water. Saline water is water with salt dissolved in it. 

– Solution is a type of homogeneous mixture composed of two or more substances.

– Solute is a substance dissolved in another substance, known as a solvent .

– Water’s density is 1 g/ml.

Salt Water Density Experiment Observation Sheet

The Salt Water Density Experiment Observation Sheet will guide your students through predictions, observations, and give students a place to write a conclusion. Teacher will need to guide student through the experiment and science explanation.

Gather Materials

The materials list is likely to be found within your kitchen. You will need 2 clear glasses, water, salt, and food coloring. Yes, that is it!

Salt Water Density Experiment Lab Procedures

Make predictions.

We started by filling both glasses up with about 1 1/2 cups of water. To create salt water, we added 2 tablespoons of salt to one of the glasses and stirred until completely dissolved.

Next, the students made their predictions about what they thought would happen when we added the food coloring to each glass. One of mine thought that the fresh water would be lighter in color while the salt water would be darker. Two other students predicted that the food coloring would produce bubbles in the salt water.

Make Observations

The first glass we put food coloring into was the fresh water. We only put 3 drops of blue food coloring in. There is no need to stir. This is the optimum time to just observe and then draw your observations. You will notice that the food coloring drops went to the bottom of the glass.

Next, we added the drops of food coloring to the salt water. As you can tell from the next photo, it immediately stopped when it hit the saline solution. It stayed in a layer above the salt water.

Draw Conclusions

the kids and I talk about why they think the food coloring reacted the way it did. In the end, we discuss how salt added mass to the density of the water causing it to become more dense. The density of water is a little less than 1 g/ml. So, if something sinks in water, like the food coloring, it is more dense. If something floats on a liquid, like the food coloring in the salt water glass, it is less dense. 

What I find interesting though, is that if you wait thirty minutes or so, the food coloring in both glasses will disperse. This is because the density of all of the liquids are close enough that the water molecules will eventually collide and join. Liquid molecules move and slip past each other. Pretty cool, huh?

DOWNLOAD Salt Water Density Experiment Observation Sheet

More free resources.

John 4:14  – But whosoever drinketh of the water that I shall give him shall never thirst; but the water that I shall give him shall be in him a well of water springing up into everlasting life.

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Density of Salt Water

Salt makes salt water denser than fresh water, and the hands-on experiment on this worksheet proves it in a colorful way! Budding scientists will learn about the density of salt water and perform an experiment with food coloring, salt water, and fresh water.

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Salt Water Density Experiment

Updated:  20 Jul 2019

A hands-on science experiment about salt water density.

Non-Editable:  PDF

Pages:  4 Pages

• Curriculum Curriculum:  NC

Years:  5 - 6

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Key Stage 2 (KS2) – Upper

Key Stage 2 (KS2) - Upper covers students in Year 5 and Year 6.

The principal focus of science teaching in upper key stage 2 is to enable pupils to develop a deeper understanding of a wide range of scientific ideas. They should do this through exploring and talking about their ideas; asking their own questions ab...

Working scientifically

Properties and changes of materials.

This science experiment allows students to identify that liquids have different observable properties and can change under different situations.

Students conduct the experiment in small groups, then complete the worksheets provided.

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This worksheet originally published in Learn Science! for grades 5-6 by © Dorling Kindersley Limited .

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