Cloud in a Jar: Make your own cloud!

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Is your child interested in looking up at the sky? Whether it’s finding shapes in the clouds, finding airplanes or helicopters, or talking about the Moon, it seems like my child is always looking up!

Creating a homemade cloud with your child is a great way to teach how clouds form and what happens inside of a cloud. This experiment shows how a cloud builds and what a cloud needs in order to form in the sky.

This experiment gives you the opportunity to talk about evaporation and condensation, what our atmosphere is made of, and why there may be turbulence inside of clouds when you are flying in an airplane.

How to make the Cloud in a Jar science experiment

Supplies you will need

For the Cloud in a Jar experiment, you’ll need:

  • A glass container with a lid (we used a Mason jar)
  • Ice
  • Hairspray
  • Hot water
  • Optional: food coloring (helps to differentiate between the water and the cloud)

Here are a couple of books about clouds to help supplement this experiment:

Supplies for the Homemade Cloud science experiment

Before you start

In this experiment, you will be using hot water to begin the evaporation process. Please keep a watchful eye on your child when handling the hot water container to ensure they do not harm themselves.

You will also need to quickly put the lid on the glass container after adding the hot water and the hairspray, so be sure to have it nearby.


Here is how to do the Cloud in a Jar experiment with your toddler:

Step 1: If using food coloring, add to hot water

We chose to add blue food coloring to the hot water

Since we need evaporation to get the process of creating a cloud started, we are going to create it by using hot water in our container. On Earth, this process is started by the Sun heating bodies of water on the ground.

Get your preschooler involved: Allow your toddler to choose the color of your water and add in the food coloring.

Step 2: Pour hot water into the container and add the hairspray

Just a small amount of hairspray added to the container should work

You only need a small amount of hairspray to begin this process. One small burst into your container should be sufficient!

Once you add the hairspray into the container, you will want to quickly add the lid onto the container to ensure no hairspray escapes.

In order for a cloud to form, it needs Cloud Condensation Nuclei (or CCN), which is a fancy phrase that means we need some sort of particles for the water vapor to hold onto.

On Earth, a few examples of CCN are:

  • Dust
  • Ash
  • Pollutants
  • Salt

The hairspray will act as the Cloud Condensation Nuclei to begin the condensation process.

Step 3: Quickly set the lid upside-down on top of the container

We used a Mason jar, so we added the sealing lid and placed the screw-top upside-down

This step simply reiterates what was mentioned in Step 2; that you will want to quickly place the lid on top of your container right after you add the hairspray. You don’t want any aerosol escaping, because that is the Cloud Condensation Nuclei we need to get the cloud started!

If you do not have a Mason jar available and only have a screw-top lid, just place the lid upside down on top of the container so you can place ice cubes on top of the container.

Step 4: Add ice cubes to the upside-down lid

By adding the ice cubes on top of the container, you are creating a point in your container’s atmosphere that is cold and favorable for the condensation process to begin.

Get your preschooler involved: Allow your toddler to add ice to the upside-down lid.

Step 5: Allow cloud to form

Once the water vapor reaches the cooler container lid, it will use the hairspray particles to begin the condensation process. When this starts, you will see your cloud begin to form.

You may also notice that the cloud starts to swirl around inside from top to bottom. Your homemade cloud has become a convective cloud!

Convective clouds are formed from convection. This is when the warmer air rises through the cloud and the cooler air (from touching the lid with the ice) sinks down.

In our experiment, this process is happening quickly and continuously, as long as we have warm enough water below and the ice above cooling the air at the top of the container.

The science behind the Cloud in a Jar experiment

This experiment is a great way to visualize how clouds form and talk about evaporation and condensation.

How it works

A cloud forms when water vapor travels up into the atmosphere and interacts with particles (dust, ash, salt, etc.) and cooler air.

Water vapor could be from lots of different sources, like bodies of water or manmade water sources (even swimming pools!). When these sources are heated by something, like the sun, some of the water is evaporated into water vapor and begin to rise into the atmosphere.

The water vapor can remain a vapor when conditions are favorable: it needs warmer air and higher atmospheric pressure. But if the water vapor continues to rise to find cooler air and/or lower atmospheric pressure, the water vapor will form into liquid droplets or ice crystals.

In order for the water vapor to form into a liquid or solid (condensation), it needs particles to begin the process. The particles create a surface for the condensation process to begin.

Once the condensation process takes place, you form a cloud!

More earth science experiments to try out with your child

FAQ about the Cloud in a Jar experiment

How do you make a cloud without hairspray?

If you do not have hairspray handy, you can still make the Cloud in a Jar experiment! Instead of the hairspray, you will be using matches. Complete steps 1 and part of step 2 (without the hairspray) of the experiment from the steps I gave above. Then, simply light a match, blow it out, and quickly add it to the jar. The smoke from the match will become the Cloud Condensation Nuclei that is needed to get the condensation process started. Then, you will continue on with steps 3 through 5.

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