water density science experiment

• Units Of Measurement
• Density Of Water

Density of Water

Water is an odourless, tasteless, transparent, and colourless chemical substance, which is the main constituent of this planet’s lakes, oceans, streams, and the fluids of most living organisms. Density is the mass per unit volume of a substance.

Table of Contents

What is the density of water.

• Factors Affecting Density of Water

Density of Water at Various Temperature Scales

Density of water experiment.

Some properties of water are given in the table below:

Watch the video and learn about the properties of water

The density of a material is defined as its mass per unit volume. It’s a measurement of how tightly matter is packed together. The density of a substance can be explained as the relationship between the mass of the substance and the volume it takes up.

The Density of Water can be defined as:

It is the weight of the water per unit volume, which depends on the temperature of the water.

Factors Affecting Water Density

There are several factors which can affect the density of a substance. Some factors which affect the density of water are given in the points below.

• The density of water is approximately 1 gram/ cubic centimetre (1 g/cm 3 ).
• It is temperature-dependent, but this relation is said to be non-linear, and also, it is unimodal in nature rather than monotonic.
• When it is cooled from room temperature, the liquid water tends to become increasingly dense, similar to other substances, but approximately at about 4°C, pure water is said to reach its maximum density.
• As it gets cooled further, it tends to expand and becomes less dense. This kind of unusual negative thermal expansion is related to strong, intermolecular forces, orientation-dependent, or interactions, and it is observed in the form of molten silica.

Read More: Thermal Expansion

Density vs Temperature 

Water does not have an absolute density as its density varies with temperature. It has a higher density in the liquid state than the solid. Check the Density Vs Temperature graph given below to understand how density changes with temperature.

Density VS Temperature Graph

You may also want to check out the topics given below!

• Unit of Density
• Relation Between Density And Volume
• What is Relative Density?
• Difference Between Density and Specific Gravity

The water density varies for different temperatures. The density (in kg/m3) of water for different temperature scale (ranging from 100 °C to -30 °C) is given in the table below.

To understand the density of water, let’s do a small experiment. We will need a tall glass cup, honey, water, coconut oil and food colouring,

Step 1: Pour a one-quarter cup of honey,

Step 2: Pour a one-quarter cup of coloured water gently on top of the honey.

Step 3: pour a one-quarter cup of coconut oil on top of the coloured water.

Now, you will notice that different substance has a different density, which means for the same volume different substances weigh differently, as they weigh differently heavier substances tend to settle at the bottom, like honey and lighter material like oil tends to float at the top.

Density of Several Liquids with Different Specific Gravity

Let’s extend our experiment further for more liquids, this time, we will use several liquids with different specific gravities , use the table given below for reference.

Frequently Asked Questions – FAQs

Why does ice float in water.

The maximum density of water occurs at around 4° Celsius. The density of ice is less than liquid water, so it floats. Upon freezing, the ice density decreases by about 9%.

What is the density of seawater?

At the sea surface, the density of ocean water is about 1027 kg/m 3 .

Why is the maximum density of water at 4°C?

The density of water is maximum at 4 °C because, at this temperature, two opposing effects are in balance.

What is the density of water at room temperature?

The density of water at room temperature (i.e., 22° C) in kg/m 3 is 997.77.

Why does water never has an absolute density?

As its density varies with temperature, water never has an absolute density.

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Select the correct answer and click on the “Finish” button Check your score and answers at the end of the quiz

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Interesting questions and nicely explained

Explanation is clear as it is easily understood. Thank you.

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Liquid Density Experiments

Liquid Density Experiment

• 3 150 mL beakers  (or use glass jars or clear plastic cups)
• vegetable oil (you can also experiment with various types of oil, i.e. olive oil, lamp oil, baby oil)
• several small objects - raisins, paperclips, pennies, small corks, etc.
• Write down what you think will happen when you place each object into the three different liquids based on your guess of the density of liquids. Because these liquids will have different densities, there will be a density tower, or different layers, that are visible, sort of like being able to see ice cubes (frozen water) in room temperature water.
• Pour 150 mL of water into beaker #1, 150 mL of corn syrup into beaker #2, and 150 mL of vegetable oil into beaker #3. (If you are using glass jars, use 2/3 cup of liquid, which is approximately 150 mL.)
• Gently set a raisin in each beaker. Does it sink or float? Write down what happens to the raisin in each beaker.
• Take the raisins out of the beakers and try a different object, such as a paperclip or cork. Record what happens in each beaker.

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Were your predictions right? Did the raisins and other objects sink and float when you expected them to? Did they float in one liquid and sink in another? Why do you think they acted the way they did?

The less dense liquid will float on top of the more dense liquid. If one of your objects floated in the corn syrup but sank in the water, what does that tell you about the densities of water and corn syrup? Take the experiment a step further to find out more.

•   600 mL beaker (or use a large jar)
• corn syrup and/or maple syrup
• vegetable oil (you can also experiment with various types of oil, i.e. olive oil, lamp oil)
• food coloring

Which is the most dense: water, corn syrup, or vegetable oil? Which is the least dense? Based on your results from experiment #1, predict which liquid you think is the most dense and which you think is the least dense.

• Place a few drops of food coloring into the beaker of water so you will be able to tell it apart from the other liquids. (This is not necessary if you are using dark corn syrup.)
• Carefully pour 200 mL of each of the liquids into a 600 mL beaker or a large jar. Let them settle.
• What happened? Did the three liquids mix together or separate into layers? Which liquid is at the bottom of the jar? Which is at the top?

Was your prediction right? If so, the liquid you thought was the most dense should be at the bottom of the jar. The next dense will float on top of that, and the least dense will float at the very top.

Now you know how the densities of the three liquids compare to each other. If you want to find out the approximate density of each, you can calculate it using this formula: Density = Mass/Volume.

On Earth, we measure mass (how much of a substance there is) by calculating weight (how heavy it is). Weigh each liquid in grams (make sure you subtract the weight of the beaker!) and then divide that number by the volume (number of milliliters) of the liquid.

The answer is density in grams (g) per milliliter (mL).

(Your answer will be more exact if you use a  graduated cylinder  instead of a beaker to measure the volume and weigh the liquid.)

Experiment #3: Hot and Cold

• 2 150 mL beakers (or use glass jars or clear plastic cups)
• food coloring (red and blue)
• Narrow Glass or beaker

Does temperature change the density of water? Write down what you think will happen when you mix cold water and hot water.

• Fill two beakers with 150 mL (2/3 cup) of water. Put several drops of blue food coloring in one beaker, and several drops of red in the second.
• Add a handful of ice to the blue water and put it in the refrigerator for a few minutes.
• Put the red beaker in the microwave for a minute.
• Take the blue beaker out of the fridge and the red beaker out of the microwave.
• Pour some of the blue water into the 10 mL graduated cylinder or narrow glass.
• Using a pipet, slowly add red water a drop at a time and watch what happens. (This part may take a little practice—if you add the red water too fast you will force the colors to mix. Hold the pipet near the surface of the water and keep trying until you get it!)

Experiment #4: Salty or Sweet

• 3 150 mL beakers (or use glass jars or clear plastic cups)
• 10 mL graduated cylinder (or tall, narrow glass)
• stir utensil

Will adding salt make the water more dense? Will adding sugar make the water more dense? Which is more dense, sugar water or saltwater? Write down what you think will happen to the density of water if you add salt or sugar.

• Fill three beakers with 150 mL (2/3 cup) of water. Add food coloring to make blue, red, and green water.
• Add 2 teaspoons of salt to the red beaker and stir until the salt is dissolved. Add 2 teaspoons of sugar to the blue water and stir until it is dissolved.
• Try putting a raisin in each of the beakers. Does it float? Remove the raisins with a spoon.
• Pour some of the red (salty) water into the graduated cylinder. Using the pipet, slowly add the blue (sugar) water one or two drops at a time. Record which sinks to the bottom and which floats on top.
• Add the green (pure) water drop-by-drop to the other two and record what happens.

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Water Density Science Experiments

How Does Salt Water Make an Egg Float?

Density is measured as the ratio of a material's mass in comparison to its volume, and is an important property of materials. All materials have their own specific density, which can sometimes be used to identify the material and predict its properties. Water is a common, everyday material that can be used to demonstrate many useful and interesting lessons about density.

Mixing Liquids

Water and oil do not mix; this is a well-known phenomenon that is actually a display of how liquids of different densities behave with each other. Liquids with low densities will float on those of higher densities. Put a little food coloring in some water to make it easier to see, then mix it in a beaker with equal volumes of corn syrup and vegetable oil. Wait and watch as the liquids separate. Which one is at the top? What does this tell you about the density of water? Try this with different liquids or chemicals for a more complex experiment.

Object Density

Since the density of water is well known, one can use it to learn about the densities of other objects. Take three beakers and pour some water into one, corn syrup into another, and vegetable oil into the last. Then take some small objects that are about the same size, like a balled-up piece of paper or foil, a small stone or a cork. Put these objects into each beaker and watch what happens. If the object floats, then its density is less than that of the liquid. This procedure, though different liquids are used, is sometimes used to find the specific gravity of oddly shaped objects with unknown densities, like rough gemstones.

Students who have been to the ocean will likely know that it is much easier to float in salt water than fresh water. This is because salt water is much denser than fresh water, and objects float when they are less dense than the substance that they are floating in. The ions in salts dissolve well in water, adding more mass but not affecting the volume very much. Take two small beakers of water and add salt to one. You'll need quite a bit of salt, at least several tablespoons. Stir to dissolve the salt, then place an uncooked egg in each beaker. If done correctly, the beakers look identical but the egg in the saltwater beaker floats.

Temperature and Density

Density is dependent upon several factors, including temperature. Hot water is less dense than cold water, and you can demonstrate this in a very visual way. Take two small jars of water, one hot and one cold, and put food coloring in each so that they can be easily seen. Put a thin piece of cardboard over the mouth of the jar of hot water and flip it upside down. Then put it over the mouth of the jar of cold water and take away the cardboard. For a short period of time, the colors will remain separate because the water on top has a lower density. This experiment can be a bit messy, so take precautions. As an alternative, you can use a dropper to put small amounts of hot water into a beaker of cold water and watch what happens. Cold water is denser than the hot water, but ice floats. Why do you think this is?

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Rainbow In A Jar: Water Density Experiment

Water science is awesome! This water density experiment  with sugar uses only a few kitchen ingredients but produces an amazing science experiment for kids!    Water experiments for kids make great hands-on learning projects for kids! In this experiment, kids will explore the density of liquids, things that dissolve in water, and color mixing.

Why is Science for Kids so Important?

Kids are curious and always looking to explore, discover, check out, and experiment to discover why things do what they do, move as they move, or change as they change!

Science learning surrounds us, inside and out. Kids love checking things out with magnifying glasses , creating chemical reactions with kitchen ingredients , learning about solids that dissolve in liquids, and exploring stored energy !

Look through all our Simple Kitchen Science Activities for home or school use!

Use the Scientific Method

This rainbow water density experiment is a fantastic opportunity to use the scientific method and record your experiment using the free mini worksheet pack below.

You can read about using the scientific method here , and find more information on the independent and dependent variables used in the density experiment below!

The first step in the scientific method is asking a question and developing a hypothesis.

What do you think will happen when you add one mixture of sugar and water to another? I think the mixtures will___________. This is the first step to diving deeper into science with kiddos and making connections!

Water Density Science Fair Project

You can also easily turn your water density experiment into a fantastic presentation along with your hypothesis. Check out the resources below to get started.

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

What is Water Density?

Density is all about the compactness of stuff in space. For this experiment, the more sugar in each glass of water, the greater the density of the water. Same space, more stuff in it! 

The denser the substance, the more likely it will sink. This is how our rainbow sugar water density tower works! Learn more about density!

Increasing the amount of sugar in the solution but keeping the water constant creates solutions with increasing densities. The more sugar you mix into the same amount of water, the higher the density of the mixture. So, density explains why the colored sugar solutions stack on top of each other inside the baster.

You could vary this water density experiment by looking at the density of different concentrations of salt dissolved in water!

YOU MAY ALSO LIKE: Viscosity Experiment For Kids

How to Make a Rainbow in a Jar

Note: You can also try a similar sugar water density activity with a Skittles rainbow in a jar .

SUPPLIES NEEDED:

• 4 Glasses or cups
• warm water and 1 cup measuring cup
• sugar and measuring teaspoon
• food coloring
• spoon and baster 

INSTRUCTIONS:

Recommended age: I suggest this experiment for upper elementary through middle school and beyond. It is not suitable for younger kids without plenty of adult assistance.

STEP 1:  Set out 6 glasses. Measure 1 cup of water into each glass. This is a great time to explain the importance of all the glasses having the same amount of water! You can read more about the scientific method for kids.

STEP 2: Add a few drops of food coloring to each glass of water. You could have your child mix the colors or help them with mixing the colors!

Note: From experience, we have found that 4 colors are the easiest to work with!

STEP 3.   Measure and add a different amount of sugar to each glass of colored water. We have since cut our experiment down to just 4 colors, but you can experiment with all of them.

• RED COLOR – 2 TBSP
• YELLOW COLOR –  4 TBSP
• GREEN COLOR – 6 TBSP
• BLUE COLOR – 8 TBSP

STEP 4.   Stir until as much of the sugar is dissolved as possible.

STEP 5.   Use your baster or pipette to create a colorful rainbow in a jar.

Tip: Have your child try two colors for an easier version!

• Squeeze the baster and put it in the red water. Release a little of the pressure to suck up some red water.
• Keep the baster squeezed, transfer it to orange, and release more to suck up some orange water.
• Continue to do this for all the colors. Leave enough pressure in the baster to get you through all six colors.

Create a Rainbow Water Density Tower

NOTE: This is probably a better experiment for elementary school or with a very patient kid. My son enjoyed trying to make the tower and simply experimenting with mixing colors.

This rainbow sugar water density tower does take a slow hand and patience.

We used a test tube from our favorite science kit! This time we found starting with the densest water {purple} worked the best.

STEP 1:   Use the baster’s measuring marks to ensure you get the same amount of each color. Add the purple to the tube.

STEP 2:   Next, add the blue, but add the blue very, very slowly. Slowly release the water along the jar’s side or glass.

STEP 3:   Continue to do the same thing,  working your way back through the colors. Slow and steady. We practiced a few times before we got a full rainbow.

You can experiment with different methods and challenge your kids to come up with a plan of action to make a rainbow in a jar.

We kept our artificial rainbow around for a couple of days. It’s so pretty in the light!

More Density Experiments to Try

To learn more about density, you could also try a  density tower  with various liquids or even a  homemade lava lamp .

Or how about a floating egg to demonstrate saltwater density ?

Check out this oil and water science with a fish theme for a preschool-friendly density activity.

More Science Experiments for Kids

Let’s look at even more awesome everyday science experiments every kid should try!

• Easy to Make Oobleck Recipe
• Fantastic Magic Milk
• Best Ever Naked Egg
• Fun Popsicle Stick Catapult

Helpful Science Resources

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

• Printable Science Project Pack 👇
• Best Science Practices (as it relates to the scientific method)
• Science Vocabulary
• All About Scientists
• Free Science Worksheets
• DIY Science Kits
• Science Tools for Kids
• Scientific Method for Kids
• Citizen Science Guide
• Join us in the Club

32 Comments

What a super clever and pretty science experiment!

Hello! I tried this experiment with my students today with little success 🙁 The purple and blue separated perfectly, but when green was introduced, it all mixed together from there on. Any thoughts? I’m so disappointed!! Your’s is PERFECT!!!

i love this website..<3

Thank you. I’ll give this a try at home – and if I am successful I’m sure my students can do it too. 🙂

Hope you have good luck! It might take a bit of practice, but it was fun to experiment.

Practice! We had a few with only a few colors too. You have to go very slowly.

it didnt work yours is perfict

It is a tougher project and you have to be quite slow and patient!

Hello, Iam a science teacher too. Thanks for sharing this experiment with us. But there is a point that ı cannot understand.

To make in a baster, squeeze baster and put in red water. Release a little of the pressure to suck up some water. Keeping it squeezed, transfer to orange, release a little more to suck up some water.

I cant understand these sentences because my english level 🙁 Should I make the test tube oily before pouring the colors? In addition Should I use syringe to take the colored waters in order to pour them? if you can explain i will be really grateful

I found this worked well when I added 4 drops of food colouring per glass rather than 2 drop per glass which I tried first. Try adding milk after, the result is really interesting!

Ours did not work at all. Huge flop even though we followed the directions explicitly. Very frustrating. Super messy. Unsuccessful.

The key is to make sure your sugar ratios are all different so they layers separate and you do need to be slow and patient adding in the layers.

We put a cup of sugar in the purple, half a cup in the blue, quarter cup for green, two tablespoons for yellow, one for orange and none for red. Slowly dribbling each color down the side of the test tube was key to avoid mixing layers.

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what grade is this experiment for?

You can use it with a mix of ages but I think it’s best for early elementary age kids. You can add our free science journal page to it as well.

So I tried to do the experiment and I found that if you actually add the different amounts of sugar to Gatorade colors it works for better results.

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Nice Blog. very easy process to do this experiment.kids also try this at home.

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We tried this experiment with 6 colors, a turkey baster and a large glass cylinder. Epic fail. Brown sugar water was our result. We found your instructions, tried again and has great success! We used 4 colors, a pipette and shot glasses and it worked beautifully! Adding the subsequent layers VERY slowly was key. The turkey baster had a tendency to dump too much water at a time. The pipette was easier to control. Thank you!

It is a bit more challenging than most of our activities. Starting with just 2 or 3 colors might help!

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How to Do the Hot and Cold Water Density Experiment

Categories Science Experiments

One of my favorite things to do are STEM activities and ocean science experiments ! I love seeing the reaction on a child’s face when they see science work before their eyes.

A lot of science experiments take a long time, but not the hot and cold water density experiment !

In this temperature density experiment, kids will experience water density, color mixing, molecule science, and a whole lot more with just one experiment that takes less than 10 minutes to complete.

Try it out at home or in the classroom!

Hot and Cold Water Density Experiment

If you love doing quick science experiments that wow, try this amazing hot and cold water experiment.

Kids will ask to do this one over and over again!

Why STEM Activities are Important for Kids

Today, science experiments for kids are more important than ever. Science and technology are huge parts of our world today, and the future will be even more science and tech-focused.

Kids who aren’t immersed in the world of science and STEM exploration from a young age will be left behind their peers, and may struggle to find work in the fast-changing landscape of future careers.

Science experiments are usually basic, but they can help spark a love of science and discovery in a child that will follow them throughout their life.

The simple science experiment that a child does today may spark their desire to discover something that will change the world in the future.

Every day, young children are using science experiments to solve real-world problems in medicine and technology that have never been uncovered before.

And all these scientific discoveries start with a firm foundation in science and STEM.

The Scientific Method for Kids

Every science experiment contains four elements:

Kids should start every science experiment with a question, even if that question is just “what will happen?”

A Hypothesis

Before doing any experiment, children should record what they believe will happen.

An Experiment

This is where the fun part comes into play. Test the hypothesis to determine if it answers the question fully.

A Recording and Analysis

As the test is completed, record what happened and analyze why.

Try different variables and try a new test to see if the original answer is confirmed or disproved.

Water Density Experiment Explanation

Here is the hot and cold water density experiment explanation.

The hot and cold water science experiment works because of the different density of hot and cold water.

Certain liquids are less dense than others. If you’ve ever made a density jar, it’s easy to see this in action.

But… water has the same density as other water, right? So why does it stay separated?

The secret is in the temperature of the water.

The molecules in hot water move faster than those in cold water. Hot water molecules bounce around and leave gaps. This makes hot water slightly less dense than cold water.

So when you put the cold water on the bottom, the denser cold water stays there.

But when you put the cold water on the top, heat molecules rise. So the colors mix right away.

Because you’re mixing primary colors, they mix into secondary colors when the hot water is on the bottom.

Supplies for the Temperature Density Experimemnt

Here are some essential supplies for the hot and cold water density experiment.

• Food coloring
• Cardstock paper

Our Favorite Water Science Kits

Here are some of our favorite water science kits that you can turn into ice science too!

• Water science kit for early elementary
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• Clean water science kit
• Water rocket kit

Water Density Experiment Set-Up

Before starting this experiment, you’ll need to laminate a small card slightly larger than the mouth of your mason jar.

Boil a pot of hot water and fill a large pitcher with ice water.

Fill three jars all the way to the top with ice water.

Fill three more jars up to the top with hot water (but don’t make it so hot that you can’t touch the sides of the jar).

Dye one cold jar yellow, one blue, and one red. Repeat for the hot jars.

More Water Experiments for Kids

• How to Make Water Slime that Looks Just Like Fresh Water!
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How to Do the Water Density Experiment

Learn how hot and cold water have different densities with this hands-on, colorful, and fun water science experiment! It's the perfect "wow" science experiment that gets strong reactions every time!

• Plastic mason jars

Instructions

First, do the experiment with the cold water on the bottom.

• Place the index card over the mouth of the hot water jar. Press slightly to make a seal.
• Flip the jar over and place it on top of the cold water jar (make sure it's a color combo that will make a secondary color).
• Line up the lip of the jars and carefully pull the card out. The water will stay separated!
• Repeat for the other four jars.
• Carefully grip the center of the jars and flip them. They will mix into secondary colors right away!
• Because cold water is denser than hot water, the colors do not mix until gravity pulls the cold water down into the hot water.

If you don't want the mess risk of flipping the jars, you can simply put the hot water jar on the top and use the index card over the cold water. Then, when you move the card out of the way the colors will mix and you won't have to flip any jars.

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Hot and Cold Water Density - Teach Kids How Temperature Effects Water Density

Posted by Admin / in Matter Experiments

An experiment to teach kids about the difference in density between hot and cold water and the natural flow of warmer or cooler water.

Materials Needed

• Two clear cups of equal size
• Index card or wax paper
• Food coloring (2 colors-blue and red)
• Casserole pan

EXPERIMENT STEPS Have an adult help with this experiment since hot water will need to be handled.

Step 1. Place a full cup of water in the freezer or refrigerator and allow it to cool for 15 minutes.

Step 2. Remove the water from the freezer and mix with a few drops of blue food coloring.

Step 3. Heat up a full cup of water. Have an adult help heat the water either in a microwave oven or on the stove. Hot tap water will work it if is very hot. Handle the hot water very carefully.

Step 4. Mix the hot water with a few drops of red food coloring.

Step 5. Place the cold (blue) water cup in the bottom of the casserole pan.

Step 6. Carefully hold the index card on top of the hot (red) water and flip it upside down, resting the cup on top of the cold (blue) water cup. If the cup opening size is larger than an index card, a piece of wax paper will also work for this step, however, if the wax paper stays in contact with hot water too long it will quickly start to stick to the cup.

Step 7. Quickly remove the index card allowing the cold water and hot water to mix. Observe what happens to the different temperature water.

SCIENCE LEARNED

Different temperature water has different density. The normal density of water is 62.4 pounds per cubic foot. Warmer water is less dense and will have a lower weight per cubic foot of space. Colder water is more dense and will weight more for each cubic foot of space. When the index card is removed between the hot and cold water, nothing really happens. The hot water stays elevated above the colder (blue) water. The cold water is more dense than the hot water. The red and blue coloring will stay separated until the water temperatures start to even out. This will actually take quite a while if the very hot and reasonably cold water is used for the experiment. The experiment cannot really be performed with the hot water starting on the bottom. The hot water will rise, but in the process the red food coloring will mix with the blue food coloring in the cold water and result in purple water.

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• matter experiments
• science experiments for kids
• water density experiment
• hot and cold water density
• water temperature density
• hot water density
• cold water density
• liquid matter experiment

posted by Admin

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