Pop Fizz

Overview:
Demonstrates the expansion of gas when pressure decreases.

Equipment:
Two 20 oz. plastic bottles of soda, preferably a clear soda, such as sprite or 7-up. A back yard. A parent. A bathtub(to clean up.)

Safety:
NEVER point a soda bottle towards yourself or another person when opening it. Don't shake it too much.

How to do the experiment:
Go to your backyard, BEFORE taking a bath. Grab a parent. Grab a bottle of soda. Shake it up. Open it immediately, but first, make sure it isn't pointing at anyone. Presto! Fizz all over the place! Grab the other bottle of soda. Shake it up. Tap on the sides so that there aren't any bubbles sticking to them. Make sure there aren't any bubbles beneath the surface of the pop. Now open this one. This time, there shouldn't be much fizz. Now, drink the soda and get a bath!

Explanation:
Before you opened the first bottle of soda, there were lots of little bubbles floating around in it. There was also a lot of pressure inside the bottle. Gas expands when you release pressure from it. All of those little bubbles expanded and overfilled the bottle. When you opened the second bottle of soda, there weren't any big bubbles in the soda. Therefore, the only gas that could expand was the gas on top of the soda. Since this is not beneath the soda, it couldn't carry any pop out of the bottle. The fizz that you did see was from bubbles that were too tiny to see before you opened it. The bath dissolved all of the sticky soda off of you.

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