hot cold water experiment

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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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!
• Fortnite Slurp Drink Water Density Experiment
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• Milk jug water wheel

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 Experiment

July 20, 2022 By Emma Vanstone Leave a Comment

This easy science activity demonstrates the difference in density between hot and cold water. It can be a bit messy so I would either do it outside or put the jars in a tray.

The demonstration works as cold water is more dense than hot water so the hot water sits on top of the cold.

When water is heated, water molecules move around faster, bounce off each other and move further apart. As there’s more space between the water molecules the density of warmer water is less than the same volume of cooler water.

You’ll need

Two small or medium glass jars

Small sheet of card

Food colouring

Tray – optional but advised

How to make hot and cold water density jars

Fill one of the jars with hot water and add a couple of drops of red food colouring.

Fill the second jar with cold water and add a drop of blue food colouring.

Check both jars are as full as possible.

Hot water on top of cold

Place a sheet of card over the jar filled with hot water and carefully place it on top of the jar with the cold water.

When the jars are balanced, carefully remove the card.

The two colours of water should remain separate.

Cold water on top of hot

Refill the jars and try again. This time place the cold water on top of the hot water.

The two colours of water should mix.

Density of water

Warm water is less dense than cold water so the red warm water sits on top of the cold water when the card is removed from between the jars.

If you put the hot water on the bottom the colours mix as the denser cold water drops down into the less dense hot water.

Our photo isn’t perfect as it’s hard to remove the card between the jars without some water spilling out, but do send me a photo if you get a better result.

Another density demonstration can be done using salt to increase the density of one jar of water. In the image below the blue water has the salt added.

Safety Notice

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

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

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Science Experiments

Easy Water Temperature Science Experiment + Video & Lab Kit

Can you see thermal energy? Yes, with just a few common kitchen items!

Although we can explain that molecules move faster when hot and slower when cold, in this science experiment kids will be able to see thermal energy in action and explore the concept hands-on.

We’ve included a materials list, printable instructions, and a simple explanation of how the experiment works. Enjoy our demonstration video to get started!

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

Supplies Needed

• 3 Glass Jars
• Room Temperature Water
• Food Coloring

Water Temperature Science Lab Kit – Only $5

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

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

Water Temperature Science Experiment Instructions

Step 1 – Begin by preparing three identical jars of water. Fill one jar with cold water, one jar with room temperature water, and one jar with hot water.

Helpful Tip: For cold water, fill the jar and put it in the fridge for an hour or two. For the room temperature water, fill the jar and leave it on the counter for an hour or two. For the hot water, boil the water on the stove or put it in the microwave for a minute or two.

Before moving to the next step, take a moment to observe the jars. The temperature of water should be the only difference. Do you think the water temperature will impact what happens when the food coloring is added to each jar? Write down your hypothesis (prediction) and then continue the experiment to see if you were correct.

Step 2 – Place 2-3 drops of food coloring in each jar and observe what happens.

You’ll notice right away that the food coloring behaves differently in each jar. Was your hypothesis correct? Do you know why the food coloring slowly mixed with the cold water and quickly mixed with the hot water? Read the how does this experiment work section before to find out the answer. 

Video Tutorial

How Does The Experiment Work?

When observing the food coloring in the water, you will immediately notice that it behaves differently based on the temperature of the water.

Even though the glasses of water look the same, the difference in the water temperature causes the molecules that make up the water to behave differently. Molecules that make up matter move faster when they are warmer because they have more thermal energy and slower when they are colder because they have less thermal energy. In this experiment, the molecules in the hot water are moving around much faster than the molecules in the cold water.

Thermal Energy is the total energy of the particles in an object.

When placed into water, food coloring will begin to mix with the water. The food coloring will mix the fastest in the hot water because the molecules are moving fast due to their increased thermal energy. These fast-moving molecules are pushing the molecules of food coloring around as they move, causing the food coloring to spread faster.

The food coloring in the room temperature water will take longer to mix with the water because the molecules are moving more slowly due to their decreased thermal energy.

Lastly, the food coloring in the cold water will take a long time to mix with the water because the molecules are moving even slower due to a further decrease in thermal energy.

More Science Fun

Eventually, the food coloring will mix throughout all of the jars. Expand on the experiment, by estimating how long it will take to mix with the water in each jar. Then set a timer and find out how close your estimate was.

In addition, you can also try these other fun experiments using water and food coloring:

• Walking Water Science Experiment – Can water walk upwards against gravity? No, not really, but what makes water seem like it defies gravity is what we’re going to explore in this easy science experiment.
• Color Changing Walking Water Science Experiment   – Much like the regular walking water science experiment, but with an added “colorful” twist.
• Coloring Changing Water Science Experiment – Science or magic? Try this experiment at home with your kids and watch their eyes light up as you pour the liquid into the bowl and “create” a new color.

Water Temperature Experiment

• Three Glass Jars

Instructions

• Begin by preparing three jars of water. Fill one with cold water, one with room temperature water, and one with hot water. Helpful Tip: For cold water, fill the jar and put it in the fridge for an hour or two. For the room temperature water, fill the jar and leave it on the counter for an hour or two. For the hot water, boil the water on the stove or put it in the microwave for a minute or two.
• Place 2-3 drops of food coloring in each jar.
• Observe what happens to the food coloring. Does it behave differently in each jar?

Reader Interactions

May 5, 2017 at 1:17 pm

thank you for u showing my kids this they love it.

March 30, 2019 at 11:58 pm

You’re amazing!!!!

April 7, 2022 at 10:35 am

I like it a lot it’s so cool that I did it for my class and got a A+

March 9, 2022 at 6:10 pm

I will be using this at Parent Science Night tomorrow!

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Learn about Hot and Cold Temperature: Easy Science Experiments for Kids

Teach kids about temperature as they perform easy science experiments with hot and cold water and the our free printable.Thank you for visiting. This post…

Teach kids about temperature as they perform easy science experiments with hot and cold water and the our free printable.

Thank you for visiting. This post may contain affiliate links to recommended products at no extra cost to you. Read our Disclosures and Terms of Use . Don't miss out again, become a  Reader here <--it's FREE. 

We did 6 different science activities to learn about temperature and the difference between hot and cold. We have a free printable activity to go along with all the hands-on activities so your little scientists can have fun understanding temperature while learning more about the world around them. Each of the activities are super simple to set up, mainly because most of the supplies come straight from your kitchen faucet.

I loved watching my kids try out these science experiments. They were so eager to check everything out and best of all their understanding of temperature grew. I think that my favorite activity was watching the food coloring disperse in hot and cold water–such a simple activity and yet so pretty to watch! If you enjoy watching your kids do science as much as I do, check out this free homeschool science curriculum . 

More Science Experiments:

• Grow a Rainbow Science Experiment
• Snowflake Symmetry Activity
• How to Make Crystal Balls

Learn about Hot and Cold Temperature Science Experiments

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• Voss Water bottle (or plastic bottle)
• Red and blue food coloring
• Thermometer (We used a candy thermometer)
• Water balloons
• Ice Cube tray
• Glass measuring cups

DIRECTIONS:

Frozen Water

Fill containers half full with water. Mark the water line with a marker or I used a rubber band because we use our water bottles a lot. Put them in the freezer until they are completely frozen. Have children look at the new water lever (ice level). The frozen line should be above the water line because when water freezes it expands because the hydrogen bonds in the water that form are more spread out then when it is in liquid state.

Red and Blue Food Coloring Race

Fill one tall container with ice cold water and another tall container with hot water (not boiling). Have child drop a few drops of red food coloring in the hot bottle and blue food coloring in the cold water and watch (this experiment is very fast so don’t look away). Technically you could use whatever color food coloring you have but since red and blue help to reinforce the difference in temperatures we used those colors. The blue food coloring should move slower through the water compared to the red food coloring because the water molecules in the hot water have more energy and move faster then the water molecules in the cold water.

Blue Ice Melt

Fill a pitcher with water and add drops of blue food coloring. Fill an ice tray with the blue water and put it in the freezer until the ice is solid. Fill a container with room temperature water and place the blue ice inside. The ice should float and the blue water that melts from the ice cube should sink. This is because cold water (and air) is more dense compared to regular temperature water and will sink in warmer water. They may have heard before that hot air rises and cold air sinks, now they can visualize it.

Hot & Cold Balloons

Fill small balloons with some air. We used water balloons. Make them relatively the same size. Place one in cold water and one in hot water. We used a pink balloon for the hot water and the blue balloon for the cold water. The hot water balloon should get larger as the air expands as it gets warm and the cold water balloon should shrink as the air inside condenses.

Thermometer Reading

After the balloon test we used our thermometer to measure the water temperatures and then we wrote the temperature on our Hot and Cold Molucule Craft (See below).

Hot and Cold Molecule Craft (Available to download for free below)

Have children glue molecules in the hot and cold cups showing their understanding of hot and cold. The hot molecules should be spread out and moving around while the cold molecules should be condensed and slow moving.

DOWNLOAD THE PRINTABLE HERE:

Print the directions here:.

Hot and Cold Temperature Science Experiments

• Thermometer

Instructions

• Frozen Water Fill containers half full with water. Mark the water line with a marker or I used a rubber band because we use our water bottles a lot. Put them in the freezer until they are completely frozen. Have children look at the new water lever (ice level). The frozen line should be above the water line because when water freezes it expands because the hydrogen bonds in the water that form are more spread out then when it is in liquid state. Red and Blue Food Coloring Race Fill one tall container with ice cold water and another tall container with hot water (not boiling). Have child drop a few drops of red food coloring in the hot bottle and blue food coloring in the cold water and watch (this experiment is very fast so don't look away). Technically you could use whatever color food coloring you have but since red and blue help to reinforce the difference in temperatures we used those colors. The blue food coloring should move slower through the water compared to the red food coloring because the water molecules in the hot water have more energy and move faster then the water molecules in the cold water. Blue Ice Melt Fill a pitcher with water and add drops of blue food coloring. Fill an ice tray with the blue water and put it in the freezer until the ice is solid. Fill a container with room temperature water and place the blue ice inside. The ice should float and the blue water that melts from the ice cube should sink. This is because cold water (and air) is more dense compared to regular temperature water and will sink in warmer water. They may have heard before that hot air rises and cold air sinks, now they can visualize it. Hot & Cold Balloons Fill small balloons with some air. We used water balloons. Make them relatively the same size. Place one in cold water and one in hot water. We used a pink balloon for the hot water and the blue balloon for the cold water. The hot water balloon should get larger as the air expands as it gets warm and the cold water balloon should shrink as the air inside condenses. Thermometer Reading After the balloon test we used our thermometer to measure the water temperatures and then we wrote the temperature on our Hot and Cold Molucule Craft Hot and Cold Molecule Craft Have children glue molecules in the hot and cold cups showing their understanding of hot and cold. The hot molecules should be spread out and moving around while the cold molecules should be condensed and slow moving. We used marshmallows. Available here: https://alittlepinchofperfect.com/learn-hot-cold-temperature-science-experiments-kids/

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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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Liquid Density Experiment

in Matter Experiments

Experiment with the density of different types of liquids.

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Water Cycle Experiment

Experiment to show all the phases of the water cycle.

Inverted Bottles

Investigate convection by using food coloring and water at different temperatures.

• Four identical wide-mouth glass bottles
• Two index cards
• Food coloring, two colors
• Hot and cold water
• Two plastic plates or trays (to hold any spilled water)
• A partner (optional)

• Cut a piece of index card so it’s slightly bigger than the opening of a bottle, and then place the card on the mouth of the second hot-water bottle. Gently tap the index card. This will help to make sure that the card is in contact with the entire rim of the bottle.

Try to do this next step at the same time to both sets of bottles: Carefully slide the card out from between each set of bottles without spilling the water. (You might need a helping hand to do this.) Watch what happens to the fluid in each set of bottles.

When you removed the cards from one set of bottles, the hot water stayed on top and the cold water stayed on the bottom, with the colors staying pretty much the same. In the other set, however, something very different happened. The hot water rose, and the cold water sank. As this motion occurred, the colors mixed. This happened because of differences in density, which is defined by the amount of material in a given volume.

Everything is made of molecules. Hot molecules move more than cold molecules, and things that are hot typically take up more space than the same things when they are cold. This means it takes fewer hot-water molecules to fill a bottle than cold-water molecules. Hot water is therefore less dense than cold water.

Gravity can separate fluids by their density. Because the cold water has more mass per unit volume than hot water, the force of gravity on a given amount of cold water is larger than that on the same amount of hot water. This forces the cold water downward and causes the hot water to be pushed or lifted upward. This motion of fluids is called convection. In the set of bottles where the hot water was above the cold water, the cold water was already on the bottom, so there was no convection.

Have you ever climbed on a stepstool or ladder to change a lightbulb? If so, you might have noticed that the air higher up in the room is warmer. This is due to convection.

The next time you go swimming in a pool, try noticing the temperature difference between the surface water and the deeper water. Again, convection may have separated fluids by density, and the water below will be cooler.

Compare two bowls of hot soup. Leave one alone and blow across the surface of the other. Compare them, and you’ll find that the bowl you blow on will cool faster than the one you leave alone. When you blow on hot soup, you help drive the process of convection. The top surface cools and sinks, and the hot soup below rises and also gets cooled.

Convection affects fluid movement on small scales, as in this Snack, but it affects fluid movement on very large scales, too. As a result, this investigation can also be used to teach earth and space science phenomena. Convection is an important part of the weather cycle. It drives ocean currents, as well as the motion of semi-solid rock within the earth. Convection even moves material in stars.

Related Snacks

BEARDED SCIENCE GUY

How to do the hot and cold water experiment, hot and cold water experiment supply list.

2 tumbler glasses

Food coloring

Small sheet of plexiglass or other hard plastic

Don't forget your safety gear!

Safety goggles

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Home » Articles » STEM » STEM Science » How to Demonstrate Diffusion with Hot and Cold Water

How to Demonstrate Diffusion with Hot and Cold Water

We all need some space sometimes, right that’s true down to a molecular level. molecules don’t like to stay too close together and will try to move to less crowded areas. that process is called diffusion and we will explore all about it in this simple but revealing experiment., article contents.

What is Diffusion?

Have you ever smelled your neighbor’s lunch on your way home? Or smelled someone’s perfume minutes after that person was gone? You experienced the diffusion!

Diffusion is a movement of particles from the area of high concentration to an area of low concentration. It usually occurs in liquids and gases.

Let’s get some complex-sounding terminology out of the way. When talking about diffusion, we often hear something about the concentration gradient (or electrical gradient if looking at electrons). Gradient just means a change in the quantity of a variable over some distance. In the case of concentration gradient, a variable that changes is the concentration of a substance. So we can define the concentration gradient as space over which the concentration of our substance changes.

For example, think of the situation when we spray the air freshener in the room. There is one spot where the concentration of our substance is very high (where we sprayed it initially) and in the rest of the room it is very low (nothing initially). Slowly concentration gradient is diffusing – our freshener is moving through the air. When the concentration gradient is diffused, we reach equilibrium – the state at which a substance is equally distributed throughout a space.

It’s important to note that particles never stop moving , even after the equilibrium is reached. Imagine two parts of the room divided by a line. It may seem like nothing is happening, but particles from both sides are moving back and forth. It’s just that it is an equal probability of them moving from left to right as it’s from right to left. So we can’t notice any net change.

Diffusion is a type of passive transport . That means it doesn’t require energy to start. It happens naturally, without any shaking or stirring.

There is also a facilitated diffusion which happens in the cell membranes when molecules are transported with the help of the proteins.

You may remember hearing about Osmosis and think about how is this different from it. It is actually a very similar concept. Osmosis is just a diffusion through the partially permeable membrane. We talked about it more in our Gummy Bear Osmosis Experiment so definitely check it out.

What causes Diffusion?

Do particles really want to move somewhere less crowded? Well, no, not in the way we would think of it. There is no planning around, just the probability.

All fluids are bound to the same physical laws – studied by Fluid mechanics , part of the physics. We usually think of fluids as liquids, but in fact, air and other types of gas are also fluids ! By definition , fluid is a substance that has no fixed shape and yields easily to external pressure.

Another property of the fluids is that they flow or move around. Molecules in fluids move around randomly and that causes collisions between them and makes them bounce off in different directions.

This random motion of particles in a fluid is called Brownian motion . It was named by the biologist Robert Brown who observed and described the phenomenon in 1827. While doing some experiments with pollen under the microscope, he noticed it wiggles in the water. He concluded that pollen must be alive. Even though his theory was far off, his observation was important in proving the existence of atoms and molecules.

Factors that influence Diffusion

There are several factors that influence the speed of diffusion. The first is the extent of the concentration gradient . The bigger the difference in concentration over the gradient, the faster diffusion occurs.

Another important factor is the distance over which our particles are moving. We can look at it as the size of a container. As you may imagine, with the bigger distance, diffusion is slower, since particles need to move further.

Then we have characteristics of the solvent and substance. The most notable is the mass of the substance and density of the solvent . Heavier molecules move more slowly; therefore, they diffuse more slowly. And it’s a similar case with the density of the solvent. As density increases, the rate of diffusion decreases. It’s harder to move through the denser solvent, therefore our molecules slow down.

And the last factor we will discuss is the temperature . Both heating and cooling change the kinetic energy of the particles in our substance. In the case of heating, we are increasing the kinetic energy of our particles and that makes them move a lot quicker. So the higher the temperature, the higher the diffusion rate.

We will demonstrate the diffusion of food coloring in water and observe how it’s affected by the difference in temperature. Onwards to the experiment!

Materials needed for demonstrating Diffusion

• 2 transparent glasses – Common clear glasses will do the trick. You probably have more than needed around the house. We need one for warm water and one for cold water so we can observe the difference in diffusion.
• Hot and cold water – The bigger the difference in temperature in two glasses, the bigger difference in diffusion will be observed. You can heat the water to near boiling or boiling state and use it as hot water. Use regular water from the pipe as “cold water”. That is enough difference to observe the effects of temperature on diffusion.
• Food coloring – Regular food coloring or some other colors like tempera (poster paint) will do the trick. Color is required to observe the diffusion in our solvent (water). To make it more fun, you can use 2 different colors. Like red for hot and blue for cold.

Instructions for demonstrating diffusion

We have a video on how to demonstrate diffusion at the start of the article so you can check it out if you prefer a video guide more. Or continue reading instructions below if you prefer step by step text guide.

• Take 2 transparent glasses and fill them with the water . In one glass, pour the cold water and in the other hot water. As we mentioned, near-boiling water for hot and regular temperature water from the pipe will be good to demonstrate the diffusion.
• Drop a few drops of food coloring in each cup . 3-4 drops are enough and you should not put too much food color. If you put too much, the concentration of food color will be too large and it will defuse too fast in both glasses. 
• Watch closely how the color spreads . You will notice how color diffuses faster in hot water. It will take longer to diffuse if there is more water, less food color and if the water is cooler.

What will you develop and learn

• What is diffusion and how it relates to osmosis
• Factors that influence diffusion
• What is Brownian motion
• How to conduct a science experiment
• That science is fun! 😊

If you liked this activity and are interested in more simple fun experiments, we recommend exploring all about the heat conduction . For more cool visuals made by chemistry, check out Lava lamp and Milk polarity experiment . And if you, like us, find the water fascinating, definitely read our article about many interesting properties of water .

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The immiscibility of hot and cold water

The density of hot and cold water.

Does water always mix with water? You might be tempted to answer yes. But the truth is that specific parameters such as temperature and gravity can prevent two solutions of the exact nature from mixing. With this experiment, you’ll understand everything!

You will need:

• Two water glasses
• Food coloring
• A rigid plastic plate
• Otherwise: a Ziploc bag and rigid cardboard of 10 cm x 10 cm

From 6 years

Difficulty : easy

This experience requires the help of an adult

Let's experiment.

Fill a glass with tap water, add a few drops of food coloring and place it in the refrigerator overnight.

The next day, fill the second glass to the brim with hot water and add a few drops of food coloring. Place your two glasses in a dish

Place your piece of hard plastic on top of the hot water glass and gently turn it over to balance it on top of the cold water glass. The air pressure in the room should keep the plastic stuck to the glass.

With the help of an adult, carefully remove the rigid plastic at the interface and observe what happens. Do the colors mix?

This step requires a lot of agility. Also, try again if you don’t get it right the first time.

Now you will repeat the experiment and place the glass of cold water over the glass of hot water. What do you observe?

Understand the experiment

Observations.

Amusingly, you find that the colored liquids do not mix when the glass of hot water is placed on top. However, the colors mix when you use tempered water in each glass or place the cold water glass on top. Can you guess what’s happening?

Hot and cold water have different densities.

The water mixes with water, right? And yet, you notice that the colors stay on their side. Does the temperature have anything to do with it? Yes, the temperature changes the density of the water. In cold water, the water molecules are closer together. Coldwater is, therefore, denser. That means that cold water weighs more than hot water. The water molecules in hot water are further apart. So hot water is less dense than cold water. For the same volume of liquid, hot water will be lighter.

If you put the glass of hot water on top of the glass of cold water, the colors do not mix. You even get the impression that the yellow color is floating on top of the blue. When you remove the plastic, the two solutions don’t mix because the heavier cold water stays at the bottom. In contrast, the lighter hot water stays on top.

When gravity gets involved.

Suppose you invert the glasses to put the cold water solution on top, the solutions mix. That makes sense because the forces of gravity will pull down the heavier cold water. It sinks, causing the colors to mix in its path. That’s why you get green.

Why do icebergs float?

If cold water is heavier, why doesn’t ice sink? And yet, ice cubes, ice floes, and icebergs float.

In the solid-state, atoms and molecules are closer together. Solids are, therefore, denser than liquids, except in the case of ice. As water molecules form, they leave larger spaces to form crystals. This decrease in density makes them lighter.

Moreover, icebergs are formed with fresh water from glaciers. But the polar seas are salty, therefore, denser. It is for all these reasons that icebergs float instead of sinking.

Did you know?

The variations of warm and cold water in the seas and oceans form powerful ocean currents circulating on the bottom and surface of the oceans. These ocean currents help redistribute the heat stored in the oceans around the world and regulate the climate.

You can try the same experiment, but this time using salt. Saltwater is heavier than pure water. By adjusting the salinity of the water, you can reproduce the density stages in a vertical container.

Other fun experiments to do at home

The color decomposition of your markers

The primary colors are cyan, yellow and magenta. Three colors from which all others derive. One way to find out what the color of the felt-tip pens is made of is to play with water, a coffee filter and use the principle of capillary action. […]

The volcano science experiment

Observing a chemical reaction in your kitchen is possible with the volcano science experiment. Build your volcano with sand. And then let’s move on to making lava. […]

A treasure map with invisible ink

Invisible ink is very useful for drawing treasure maps or writing secret messages. Only those who know chemistry will find a way to reveal your message. Let’s use onion juice to prepare the invisible ink. […]

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Hot and Cold Water Science EXPERIMENT

Are you looking for a science experiment to do with your kids at home? Then, wow your preschoolers or kindergarteners with a science experiment that teaches them how the density of water changes when it is heated. After all, who doesn’t enjoy science activities for kindergarten that only require common household items?

SUPPLIES FOR THE WATER SCIENCE EXPERIMENT

You will need an adult to supervise this activity as it involves hot water.

• Two identical wide mouthed small clear glass jars
• Food Coloring – Red and Blue
• Index or plastic card ( Old playing card can be used if it covers the mouth of the jar )
• Shallow Dish/Plate or baking pan
• Hot and Cold Water

How do you do hot and cold water density experiment?

Fill one jar with cold water and the other with hot water.

Pour blue food coloring into the cold water and red food coloring into the hot water.

Make sure both jars are completely filled with water. To avoid spills, place them in the shallow plate.

Tap the card gently on top of the hot water jar. The card should completely cover the jar’s mouth. It will aid in the formation of a seal between the water and the jar.

Pick up the hot water jar with care (you’ll need an adult for this part) and turn it completely upside-down.

If the jar is tilted but not completely turned over, the water will gush out and make a mess. So, without hesitation, flip the jar over.

You may not need to place your hand on the card because the vacuum created inside the jar keeps it on the surface.

Before attempting it with hot water, it is best to practice turning the jar upside down with an index card placed on top of it under the sink using tap water.

Place the red jar upside down on top of the blue jar. Check that the edges of both jars are perfectly aligned all around.

Allow someone to hold both jars while you slowly and patiently pull out the card from between the jars.

RELATED POST : HOW DOES WATER WORK AS A MAGNIFYING GLASS

DENSITY EXPERIMENT : THE SCIENCE OF Hot and Cold Water

Why does hot and cold water not mix?

Empty and clean both jars. Carry out the previous experiment, but this time turn the blue jar upside down and place it on top of the red jar. What happens next? Why does the water mix this time?

The reason for this is that when two liquids of different densities are combined, the liquid with lower density floats on top of the denser liquid.

Hot water has a lower density than cold water.

When water is heated, the water molecules begin to bounce off each other, causing them to move farther apart and thus create more space between the molecules.

Eventually, a volume of hot water contains fewer molecules and weighs less than a volume of cold water.

As a result, hot water is less dense than cold water.

RELATED POST : WHAT IS WATER COHESION AND WHY IS IT IMPORTANT

When you place the jar containing hot water on top of the jar containing cold water, the cold water does not have to rise because it is denser than the hot water and thus remains at the bottom.

When you place the jar with cold water on top of the jar with hot water, the hot water rises to the top because it is less dense, mixing with the cold water along the way and creating purple water.

FURTHER EXTENSION ON Water Density

Try the same experiment with a jar of salted water and a jar of plain water. And let us know in the comments section which one is more dense.

Check out some of these great books on science experiments that are simple and fun to do at home if you want to stir up your children’s scientific curiosity.

(Disclosure : Some of the links below are affiliate links, meaning, at no additional cost to you, I will earn a commission if you click through and make a purchase)

Thanks for reading! We hope you enjoyed this post on hot and cold water science experiments. Be sure to check out our other posts for more fun and interesting STEM activities you can do at home with your kids. As always, if you have any questions or comments, feel free to leave them below. Happy experimenting!

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February 14, 2021 at 2:30 pm

Oh love a bit of easy STEM! maybe this is a good one for half term, if I have jars….

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Balloon In Hot and Cold Water – Experiment

• March 30, 2021
• 7-9 Year Olds , Household Items , Physics

Let’s discuss about ‘Balloon in hot and cold water experiment’ in this article. This interesting balloon experiment helps children to learn about density , surface tension , and air pressure .

Balloon in hot and cold water experiment

• The volume of air changes based on the temperature surrounding it.
• Air expands or contracts based on increase or decrease in surrounding temperature.

Things you need to do Balloon Experiment

1) Two plastic/ glass container (bottles)

2) Balloons

3) Hot Water

4) Ice cubes as a cold water source

5) Containers to place hot and cold water

Preparation Steps

1) You can prepare your children or students by asking “How can you inflate the Balloon without touching it?”.

2) Note down their expected answers. But discuss their solutions only after performing the experiment to catch the science concepts behind it easily.

Step by Step Directions

Let’s start with the hot air experiment.

Step-1: 

Take a glass container and add cold water. Then, add few ice cubes to it to keep it cold.

Step-2: 

Pick another glass container and add some amount of hot water into it. Ensure the hot water’s hotness need not to be sizzling.

As step 3, bring our Balloon over the neck or mouth of the crystal clear plastic bottle in an upside-down position. And fix the mouth of the Balloon to the mouth of the bottle as shown in the picture.

Make sure the bottle is empty before you attach the Balloon to it.

Repeat the same method and prepare another set of water bottle and Balloon using the other empty bottle.

In this step, keep the ballon attached bottle inside the container, which consists of hot water. Let the bottle sit in hot water for some time.

You will observe the Balloon starts inflating itself without any external force. Amazing, isn’t it!?

Step-5: 

And then bring the same and another set of water bottle into the container which consists of cold water. And allow it to sit for some time to see the results.

You will observe the Balloon starts shrinking itself by deflating the air inside it.

Note:  If you feel the hot water is becoming cool, replace it with another hot water cup. In the same way, if you feel the cold water is becoming hot due to outside temperature impact, add some more ice cubes and make it cool. In this way, you can maintain the temperatures of the water while repeating the experiments.

Science Behind Expanding Balloon on Hot Water

The quantity of air occupied in a particular space, i.e., an open or closed container, denotes ‘Volume.’ 

Well, an empty water bottle is also populated with a certain amount of air molecules inside it—the air molecules inside and outside the bottle move with equal pressures at normal surrounding conditions.

In this activity, when we attach a balloon over the bottle’s mouth and place it in a hot water container, the Balloon starts inflating. It is because the hot air molecules enter into the Balloon from the bottle, which is in a hot water container.

These hot air molecules move faster inside the Balloon and occupy more space as they become less dense than usual. When they become less dense, it requires more space to settle, and that is why the Balloon starts inflating to provide more space for hot air molecules.

And when the Balloon inflates in hot water, bring it into the container containing cold water. Here, the cold air molecules replace the hot air molecules because hot air molecules cool down due to cold water.

When the air molecules become colder, air molecules’ density gets back to a denser state and requires less space to occupy. That is why the inflated Balloon deflates when the bottle is placed inside a cold water container.

This is how the volume of air calculated:

Volume= Mass x Density

Safety Tips

Have adult supervision at all times during the experiment to avoid any unforeseen incidents.

Suggested to wear gloves and safety glasses while doing experiments with hot water.

Avoid handling hot water by small kids.

Learning for Elementary, Middle School, and High School Students

The same experiment can be used differently based on the level /grade of the students.

Elementary Students

When kids are in elementary school, it is the best time to learn about different states of matter, i.e., solids, liquids, and gases. Solids and liquids are visible to the naked eye, and hence students can easily catch up with the properties and characteristics. And it is easy for them to compare various objects and liquid things and determine the state of matter properties.

But when coming to gases, it is difficult for them to determine their properties because gases won’t appear to the naked eye, and children go confused. That is why we need to explain them clearly by concentrating much on performing various science experiments that involve gases. One such experiment is the ‘Balloon in a bottle’ experiment.

Through this experiment, students can quickly learn about gases and their properties.

Middle School Students

In middle school, students focus on macroscopic particles and determine the objects around them and tell whether they have solid or liquid or gaseous properties. Because at this level, they will get to learn about states of matter in regards to their arrangement, position, and movement. Also, they can explore that all forms of matter are made of atoms and molecules that consist of weight, especially gases. As the air is invisible, they think that gases do not have mass, but they learn about gases containing mass with this experiment.

Besides, they can explain the conservation of matter with a good reason using the concept of closed systems.

High School Students

At this level, as the name suggests, students become sharp and can apply their knowledge on gases. This knowledge helps in understanding even the difficult context of gases, i.e., ‘Gas Laws.’ Also, they can apply Charles Law and explain Gas Law. And using conservation of matter principles and laws, they will make out the differences in temperatures and their relation to the volume of gas.

In this way, students at different school grades learn the gaseous properties by performing this super classic experiment of ‘Balloon in a Bottle.’

Laws Behind the Experiment

Gas Law or Gas Laws is/are a collection of laws which include Boyle’s Law, Charles’s Law, Gay-Lussac’s Law, Ideal Gas Law, and Avogadro’s Law. These laws combine to state how an amount of gas reacts to changes in temperature, pressure, and temperature. The following are such statements these combined laws work on:

1) The complete temperature of a gas

2) The amount of volume working with a gas

3) The amount of pressure experienced between the walls of a container and a gas

4) The mass of a gas

The above-mentioned combination laws were a great invention during the 18th century, and here are the definitions of each law:

    Boyle’s Law:  The law which states the kith and kin between the volume and pressure of a given amount of gas is nothing but Boyle’s Law.

    Charles’s Law:  Charles’s Law is the law that tells about the absolute temperature of a gas and its association with the volume employed by it. 

    Avogadro’s Law:  The type of law which states the correlation between the number of moles of a gas and the amount of volume occupied by it refers to Avogadro’s Law. 

    Gay-Lussac’s Law:  Gay-Lussac’s Law tells that the relation between the absolute temperature and its pressure is directly proportional at constant volume. 

    Ideal Gas Law:  Ideal gas law is a combination of three laws, i.e., Boyle’s Law, Charles’s Law, Avogadro’s Law, and hence refers to the term ‘combined gas law.’ This law states the differential behavior of gases at different conditions and concludes that a gas’s pressure is directly proportional to the absolute temperature. 

Pressure, volume, and temperature are the three significant physical factors that determine the behavior of gases. When these parameters are at standard conditions, the activities of all types of gases remain the same. The states of gases can vary based on the condition. 

So, the gas law and all other five laws state all gases’ behavior is associating with all three physical parameters.

Boyle’s Law Formula: P∝1/V

Charles’s Law Formula: V∝T

Avogadro’s Law Formula: V ∝ n

Ideal Gas Law Formula: PV= nRT

Gay-Lussac’s Law Formula: P ∝ T

Here, P= Pressure of the gas, V= Volume of the gas, T= Absolute Temperature of a gas, n= Number of moles, R= Equilibrium Constant.

Here are some worksheets that would complement the science experiment. Attempting these worksheets might help studnets to sustain the knowledge gained through the experiment. On the other hand, teachers use these worksheets to understand and monitor student’s previous and current knowledge.

https://scied.ucar.edu/sites/default/files/files/activity_files/BalloonOnBottle_0.pdf

https://www.flinnsci.com/api/library/Download/e2dfff9fc2324f51889429583a51ac63

https://ps21pd.weebly.com/uploads/1/2/0/6/12065719/kinetic_theory_-_hot_and_cold_balloons.pdf

https://www.sciencenorth.ca/sites/default/files/2020/June%202%20Grade%207%20Particle%20Theory%20Offline%20ENG.pdf

Practical Applications

Let’s learn how to apply these science concepts in real life applications happening around us.

Hot air balloon:  Yes, the science behind hot air balloon and Balloon in the bottle activities is similar, i.e., hot air rises, sending the cool air to replace the space created by it. When you provide heat flames in the hot air balloon set up, the heat energy enters into the Balloon.

Generally, the hot air consists of less dense air molecules, which tend to rise. That’s why and the hot air balloon rises in the sky until they provide enough heat.

Not only air, any substance that exhibits less dense molecules than the surrounding gaseous or liquid matters float . Forex: Wood floats on top of the water because wood consists of less dense molecules than water. This phenomenon of increasing the molecules’ speed regarding the increase in temperature of a gas refers to ‘Thermal Expansion.’ And the wonder of floating objects due to the pressure or force exerted is ‘Buoyancy.’

Sun Producing Wind on Earth:  The winds produced by Sun on the Earth also exhibit the same phenomenon, i.e., thermal expansion and buoyancy.

Earth’s temperature is uncertain, so we cannot predict its long-term weather and climatic conditions. It is because different parts of Earth receive heat from Sunlight at different times as Earth is round and rotating.

So, the Sun can’t provide Sunlight to all parts of the Earth at the same time. Hence, Earth receives different air temperatures at places closer to the surface of the Earth. Besides, the Sun’s angle is focussing its Sunlight on the Earth also plays a significant role in changing the temperatures of Earth.

According to the above concepts, several continents on Earth receive more heat than other continents. Comparing land and water, land absorbs more heat faster than water, and therefore we see continents with more land exhibits high temperatures.

But during nights land releases heat more quickly than air and hence we feel cooler climates at night time. In this way, Earth reveals different climatic conditions and atmospheric temperatures during the day and night times.

Let us discuss these concepts in detail with a practical example, i.e., Off-shore and On-shore Winds. During nights, the oceans’ surface gets warmer so quickly because the surrounding land cools down and shows lesser temperatures.

As a result, the warmer air becomes less dense and rises upwards, leaving the space on the surface occupied by the cold air from the land. Thus, creating the off-shore winds that produce renewable and pure energy.

And at daytime, we experience on-shore winds that mean the land absorbs more heat from the Sun and exhibits warmer air. This hot air does not remain on the land surface; instead, it rises into the air because it consists of less dense air molecules.

Simultaneously, the temperature at the ocean level exhibits less heat than the land surface temperature. So, the cold air from the ocean surface replaces the hot air molecules’ space creating on-shore winds.

Lesson Plan

Here is the best lesson plan on the ‘Balloon in hot and cold water’ experiment.

Preparations

1) Ask the students whether they can inflate the Balloon without touching it. Note down their answers and discuss their solutions after the experiment.

2) First, invite your student’s answers and discuss their solutions with a scientific reason.

3) You can encourage and inspire students by telling them that they are upcoming engineers, chemists, and other respectable designations. Forex: if a student predicts the answer would be ‘by adding baking soda and vinegar,’ explain why his response went wrong. Then, encourage him by saying he/she is thinking smartly like a chemist. In this way, depending on their predictions, a teacher can inspire them with specific designations.  

4) If a student does not respond to your challenge of inflating a balloon without touching it, then give him an example and ask him/her to compare. Let the student come up with his/her answer with a bit of explanation.

Guide your students on the instructions of the ‘Balloon in hot and cold water’ experiment step by step, clearly as mentioned at the top of this post. You can also ask and discuss a few questions related to the subject while experimenting. Such that students feel more encouraged and involved in the topic rather than feeling bored.

Here are the basic questions you can discuss with students:

1) Why does the Balloon inflated on itself?

2) What is the difference between hot and cold water changes and their impact on the Balloon?

3) How long the Balloon takes time to inflate itself in hot water?

Explain about Misconceptions

Students think that hot air blows up the Balloon as the hot air rises upwards. But prove it as a misconception by reversing the bottle with an inflated balloon. Still, the Balloon remains inflated without deflating. It is because hot air rises when there is cold air beside it.

Finally, explain the background science involved in this experiment and discuss students’ predicted answers with a scientific reason. Tell them clearly that their answers may not apply in this science activity, but they may use them in another way of experimenting.

In hot water, the Balloon inflated because of hot air molecules, and in cold water, the Balloon deflated because of cold air molecules. The hot air molecules are less dense in weight and tend to rise and occupy more space. That’s the reason the hot air molecules travel inside the Balloon and make it expand. In contrast, the cold air molecules are denser in weight and require less space, causing the Balloon to deflate.

Take an empty plastic water bottle. Attach a balloon (make sure it is not leaking anywhere on its surface) to the bottle’s mouth using its neck part by placing it upside down. That means the mouth of the Balloon and the bottle gets attached in opposite directions using their mouthparts. Now place the bottle set up in a container that consists of hot water in it. Leave it for some time. The Balloon starts inflating by filling its inside part with hot air molecules.

Bring the Balloon’s mouth part in an upside-down position over the neck part of the bottle. And then stretch the Balloon’s opening around the neck part of the bottle. But before that, you need to uncap the bottle. That’s it! Your Balloon’s opening nicely sits over the bottleneck part.

Boyle’s Law is valid at very high temperatures until or unless the gas remains as a gaseous matter. Because at high temperatures, the gases may change their state of mass, for which Boyle’s law is not applicable. Boyle’s law tells that the volume and pressure of a gas-related each other quite the opposite.

When you squeeze the bottle, the Balloon begins inflating itself because we squeeze some air molecules into it while squeezing the bottle. And due to more air occupying inside the Balloon, the Balloon starts expanding and inflates itself to fit the air molecules coming inside. When you stop squeezing the bottle, the balloon deflates.

When you let the Balloon warm up again, it starts inflating itself because of warmer air molecules. The warmer air molecules rise and enter into the Balloon, making it expand. Hot air molecules are less dense in weight and tend to travel upwards. And they require more space since they like to scatter in larger areas.

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Playing With Rain

Explore the World Around You

in Instagram Feed · Kids Science Experiments · Weather Science

Hot and Cold Balloon Experiment

Share with your friends!

Did you know that inflating and deflating a balloon can be as simple as heating up or cooling down the air inside the balloon!? Let’s jump in and learn how to do this fun Hot and Cold Balloon Experiment.

Get more fun and easy Atmospheric Pressure Experiments here!

My favorite thing about this cool science experiment is how easy it is to do at home with your kids…and they will love it!

This post may contain affiliate links. As an Amazon Associate, I earn from qualifying purchases.

Table of Contents

Supplies Needed:

• Empty plastic bottle
• 1 Bowl of Hot Water
• 1 Bowl of Cold Ice Water

How to Inflate a Balloon With a Bottle

• Fill a bowl with hot water and another bowl with ice cold water.
• Grab an empty plastic bottle and attach a balloon to the top of the bottle.
• Set the bottle in the bowl of cold water and the balloon will not inflate.
• Place the bottle in the bowl of hot water and watch as the balloon inflates!
• Now move the bottle back to the bowl of cold water to watch the balloon deflate again!

Step 1: Get a Bowl of Hot Water and a Bowl of Cold Water

For the best and most dramatic performance of this experiment, you want your cold water to be as cold as possible, and your hot water to be as hot as safely possible.

I prefer to mix some ice into a large bowl with very cold water to make sure my ice water is very very cold. Then, using adult supervision, heat up some water in the microwave or on the stovetop in a separate large bowl or pot.

The water needs to be hot and steamy, but you don’t want it to be boiling either.

Step 2: Attach a Balloon to the Top of an Empty Bottle

Stretch the mouth of a large balloon over the opening of an empty plastic bottle. Sometimes it even helps to inflate the balloon first and deflate it to stretch the latex out a little bit before attaching it to the bottle.

It also helps to use your fingers to stretch the mouth and neck of the balloon out a little bit. The larger the balloon you use, the easier this step will be to slide the balloon mouth onto the bottle opening.

Step 3: Place the Bottle in the Cold Water

After you attach the deflated balloon to the bottle, place the bottle into the bowl of cold water and pay attention to what happens.

You should not notice much of a change with the balloon. In fact, it may even contract and shrink even smaller than before, and it certainly will not inflate in the cold water.

Step 4: Put the Bottle into Hot Water and Watch The Balloon Inflate

When you move the bottle and balloon from the cold water and place it into the hot water you should see a pretty dramatic change in the balloon. It should start to fill with air and inflate!

The balloon likely won’t get super big, because it needs more air pressure to stretch the latex a lot, but it will noticeably expand and get bigger in the hot water!

Step 5: Move the Bottle Back to the Cold Water

Put this experiment in reverse by moving the bottle from the hot water back into the cold water again. What do you think will happen to the balloon!?

You guessed it! The balloon will quickly shrink and deflate again once the bottle is placed in the bowl of cold water! This Baking Soda and Vinegar Balloon Experiment is another super cool way to inflate a balloon too!

Now it’s time to dive into the science behind how this hot and cold balloon experiment works!

How Does Temperature Affect the Size of a Balloon?

Generally speaking, the higher the temperature of the air inside a balloon, the larger and more inflated the balloon will become. On the flip side, the colder the air is inside the balloon, the balloon will shrink and deflate.

This shrinking and expanding of the balloon due to temperature is all thanks to a fancy scientific equation called the ideal gas law .

The Ideal gas law basically means as temperature increases, the volume of air inside the balloon does as well. This is because heat energizes the gas (air) molecules and they bounce into each other faster and faster.

As the bottle with the balloon attached is placed in hot water, the air inside the bottle heats up and the molecules move around faster and increase the volume and air pressure enough to inflate the balloon.

Then as the bottle is moved back into the cold water, the air molecules lose energy and slow down. They don’t bounce around as quickly and the volume and pressure decrease as the balloon deflates.

PIN THIS EXPERIMENT FOR LATER

More Fun Experiments For Kids:

• Bouncy Egg Science Experiment
• Bottle Thermometer Experiment
• Light Refraction in Water

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MORE ABOUT PLAYING WITH RAIN

LET’S CONNECT

Search for more ideas, create at your own risk.

All content on this blog was created for inspiration and entertainment purposes. Creating anything with the suggested tools, products or methods, is under your own risk!

Kitchen Science Experiments to Try at Home

• Electricity
• Kitchen Science Experiments

Strange Temperatures

Part of the show hot nectar, warming weather and birds missing the spring, dscf0289.jpg.

To do this experiment, you will need:

Three bowls or washing up basins large enough to put your hand in

- Warm water (NOTE - be careful not to make the water too hot!)

- Cold water, with a few ice cubes in it

- Medium temperature water

How to do the experiment:

1 - Fill one bowl with warm water, one with iced water and one with medium water.

2 - Put one hand into the warm water and one in the iced water for one minute.

3 - Take your hands out of the water and put them both into the medium water. How does the water feel?

So what's going on?

When you put your hands into the medium temperature water, the hand that's been in the cold water feels warmer while the one that was in the warm water feels cold.

Why is this?

It's because your senses are relative. They don't measure an absolute temperature or an absolute brightness of light; they make their measurements relative to the things around it. In the case of this experiment, the temperature sensors on your hands measure the temperature of the water relative to the temperature of your hand. If the water is warmer than your hand, it feels warm, and if it is colder than your hand, it feels cold.

Measuring temperature relative to a certain object (such as your hand) is fine if your hand stays at a constant temperature - but it doesn't. If you keep your hand in cold water for a long time, the temperature of your hand starts to drop. This means that the reference point to judge temperature by has changed. Water that once felt cold now feels relatively warm compared to your cold hand.

The opposite happens when you transfer your hand from the hot water into the medium water. Your hand is warm and so the medium water feels relatively cold.

The effect is most obvious in this experiment when you transfer a cold and a hot hand into medium temperature water at the same time: one hand is telling you the water is warm while the other is saying that it's cold, even though the actual temperature of the water is the same throughout!

Your hands give two different answers and your senses are confused!

This effect can be seen in other situations too. When people run a bath they generally tend to stir it with one hand. As a result, people should always test the water with the OTHER hand before getting in. This is because the hand that's been stirring will get used to the high temperature and send messages to the brain saying that the water isn't hot. However, as soon as you jump in with cold feet, the water will feel relatively scalding - so be warned!

Another example is when children are told not to wear their coats indoors because they won't feel the benefit. If you get used to being really hot and snuggly inside a coat in the house, as soon as you go outside you feel cold (like the hot hand going into medium water). However, if you keep your coat on the peg while in the house and only put it on outside, the addition of a warm coat to a warm (rather than hot) body means that the shock of braving a cold winter's day is relatively less.

You can even see this effect with your ears! If you've been in a noisy room and then move into another room that's playing a quiet radio, you can hardly hear it at all. However, if you sit there for five minutes you can start to hear the radio loudly, even though it's still at the same volume.

So the moral of the story is: don't believe everything your senses tell you!

Ingredients

Warm water (NOTE - be careful not to make the water too hot!)

Cold water with a few ice cubes in it

Luke warm water

Instructions

3 - Take your hands out of the water and put them both into the medium water . How does the water feel?

When you put your hands into the medium temperature water, the hand that's been in the cold water feels warmer while the one that was in the warm water feels cold, even though they are both feeling water that is the same temperature.

Explanation

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