Cloud in a Jar Weather Experiment

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In the summer of Arizona, there is no question that when you leave something wet outside, it will be dry in a few hours. Where did all the water go?

In this cloud in a jar experiment, we are going to explore how the fluffy white clouds we see in the sky are formed. One important element of this experiment is using a match to create smoke particles in the jar for the water to condense on to. 

Cloud in a Jar Water

If you are not comfortable using a match, you can substitute with hairspray. Simply spray a little bit of hairspray into the jar instead of throwing the match into the water. However, I have to say my kids loved the little fire display and it made the experiment all the more exciting!

How to Make Cloud in a Jar

Materials:

  • Clear jar with lid
  • Warm water
  • Ice
  • Matches

Instructions:

1. Fill the jar about ¼ full of hot water. I recommend not using boiling water, as it would fog up the walls of the jar and make it difficult to see the cloud.

2. If you do see water condense on the walls of the jar, swirl the water around a little to get rid of the condensation.

3. Prepare the lid by turning it upside down and placing some ice on top.

Cloud in a Jar Materials

4. Light a match (adult only please!) and hold the fire for a few seconds inside the jar. Careful not to burn your fingers!

5. Drop the match into the jar.

6. QUICKLY place the lid with the ice on the jar.

7. Watch the cloud form inside the jar!

Cloud in a Jar

Did you manage to get the cloud to form inside your jar? If not, try putting on the lid a little faster so the smoke doesn’t escape. Another possibility is that your water is not hot enough.

After a few minutes, you can lift the lid and let your cloud escape. It was so cool watching the cloud slowly float up and dissipate into the air. My kids enjoyed blowing on it or fanning it with their hands. I tried to capture the smoke in a photo but it was difficult to see.

Cloud in a Jar Smoke Escape Top

We added the blue food coloring just for fun, but it didn’t do anything. I was curious to see if it would affect how well we could see the cloud, but I don’t think there was a visible effect.

We repeated this experiment over and over again because the kids wanted me to light the matches. Not the point of the experiment, I know, but hey the kids still learned about cloud formation in the end and had lots of fun!

Science Behind the Cloud in a Jar Experiment

Water from everywhere, including lakes, rivers, and oceans, evaporates into the atmosphere as part of the water cycle. Meaning, the water turns into water vapor and travels in the air.

When the air rises in the atmosphere, there is less pressure and the air cools (demonstrated by the ice in the lid). The air can’t hold as much water as before, and the vapor condenses into small water droplets. 

The water droplets condense on dust particles in the air (in our case, the smoke from the match) and form a cloud.

Cloud in a Jar Closeup

After you make cloud in a jar, it’s time for the cloud to rain! Check out how to make rain in a jar here.

Another fun weather science experiment is the tornado in a bottle. Your kids will love making the water vortex and you can use it as a “calm down” toy afterward.

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