Kids, try this at home!

Materials: 

Bottle with a metal lid, a hammer and nail, a straw, glue, adhesive tap, a paper cup, vinegar, and sodium bicarbonate

Instructions: 

1)  With an adult, use a hammer and nail to make a hole in the center of the metal lid of the bottle. 

2) Cut the straw down to a three-inch piece and put it through the hole, leaving a quarter inch of the straw above the lid.  Cover the rest of the open hole around the straw with glue and let it dry. 

3)  Fill half of the bottle with vinegar.

4)  Fill half of the paper cup with sodium bicarbonate.  Use adhesive tape to secure it. 

5)  Put the lid back on the bottle, securing it tightly.  Go outside and shake the bottle, keeping your finger over the straw.  Then, point the straw towards the ground.  What happens? 

Explanation:

When you mix vinegar with sodium bicarbonate and shake the bottle, you create a chemical reaction.  This reaction creates a lot of carbon dioxide gas bubbles, making foam.  Then, the gas bubbles increase the pressure inside the bottle, making the mixture fly out the straw in the lid.  Many fire extinguishers work in the same way, but they use other chemicals.