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Make Rain Clouds in a Bottle
Try This Science Lab

Follow these steps to make rain clouds in a bottle! Done right, this experiment has the most rewarding whoosh.

WHAT'S HAPPENING?

You’re mimicking the part of Earth’s water cycle in which evaporated water (water vapor) cools and condenses, forming clouds as they connect with dust. In this experiment, the alcohol acts like the dust, providing something cool for water droplets to attach to.

When you pressurize the soda bottle by pumping air in, the air molecules collide with each other and warm the bottle. Releasing the pressure causes the water vapor to condense quickly, forming a cloud.

 

 

YOU WILL NEED

  • two-liter soda bottle, clean and dry
  • rubbing alcohol
  • bicycle pump with needle
  • cork
  • skewer, drill bit, big needle, or something else you can use to make a path for the pump needle to go through the cork
  • optional: duct tape
Make rain clouds in a bottle

STEP ONE

Fit your cork to your bottle. You may need to shave the sides off the cork to get a tight fit. Your aim here is the tightest possible seal. Then trim the cork to the length of the bike pump needle. You want the needle to be able to pass through the cork into the bottle, maintaining a tight seal.

Make rain clouds in a bottle

STEP TWO

Make a path for the cork, using your skewer, drill bit, or needle. Be sure the object you use to pierce the cork is narrower than the bike pump needle, or you won’t have a tight seal. When the cork is ready, take it out of the bottle.

 

 

STEP THREE

Pour one teaspoon of rubbing alcohol into the bottle and screw the cap back on.

Make rain clouds in a bottle

STEP FOUR

With the cap on, turn the bottle horizontal and roll it so that the alcohol sloshes around and coats the inside of the bottle thoroughly and evenly.

 

Make rain clouds in a bottle

 

 

STEP FIVE

Insert the cork.

Make rain clouds in a bottle

 

 

STEP SIX

Insert the bike pump needle in the cork, then pump the bike pump four or five times. Sometimes when you do this the cork will blow and you’ll have your reaction. Other times you’ll have to pump a few times more, then stop and pull the needle out.

Make rain clouds in a bottle

WHAT TO EXPECT

Once the pressure is released—either because the cork blows or the needle is removed—a cloud should form quickly and dramatically in the bottle. Note: Aim the bottle away from you and anyone else.

 

GLITCH?

No cloud? Your seal isn’t tight enough. Try a different cork, or use duct tape to tighten the seal.

 

 

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BONUS: REVERSE THE EXPERIMENT!

Before the cloud disappears, put the needle back in and pump a couple more times. The cloud should disappear as quickly as it came. Release the pressure, and the cloud will reform.

DO COOL EXPERIMENTS!

You can be a scientist!

Eggs-periments

SQUISH IT!

Rock On

RELEASE THE GAS!

What kind of scientist would you like to be?