Clouds are made when warm, humid air rises in the sky until it starts to get cold. The water in the air, known as water vapor, wants to turn back into a liquid, but it can’t without a surface to stick to. Luckily, there are little pieces of dust and pollen, called particles, in the air. Water vapor sticks to these particles and turns back into a liquid. Turning from vapor into liquid is called condensation. This is how we get clouds in the sky!

*You will need an adult’s help for this activity*

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Materials:

- Matches

- Warm Water

- 2-Liter Clear Bottle

- Tablespoon

Optional Materials:

- Dark Paper or Cloth

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Procedure:

1. Add a little bit of warm water to the bottle – no more than 2 tablespoons.

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2. Ask an adult for help with this step! Light a match and let it burn for 1 – 2seconds, then blow it out. You want it to produce smoke.

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3. Hold the bottle on its side and hold the smoking match inside the bottle. You are trying to collect some of the smoke inside the bottle.

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4. Drop the match in the bottle and immediately close the bottle.

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*Optional: hold the bottle in front of the dark paper or cloth while you do the next step.*

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5. Squeeze the bottle three or four times. It will take a few squeezes for the cloud to form.

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6. When you stop squeezing the fourth time, you should see a cloud form! When you squeeze the bottle again, the cloud should disappear!

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What’s happening? There is water vapor all around us in the air. When this water vapor is near the ground, it is warmer than when it rises up into the sky where it becomes colder and forms clouds. However, the water vapor needs particles to stick to in order to become clouds. In your bottle, you added smoke which became the particles the water vapor needed to stick to. When you squeezed the bottle, the pressure inside increased which also made the air warmer. When you released the bottle, the pressure decreased and so did the temperature allowing the water vapor to condense and form a mini cloud!