Inflate a Balloon on a Bottle

Blowing up a balloon on your own can be a hassle...the balloon tastes weird and sometimes it is tough to stretch the balloon out.  I'm not exactly Billy Mays, but I'm going to try to sell you this great new way (OK, it's not new, it's a reaction as old as time) to blow up a balloon that removes all of the hassle of having to do it yourself.  It's safe, fun, easy, and you could just learn a little science along the way.  For only $19.95...nevermind, it's cheap and you probably have everything you need at home to do it yourself already.

What you need:  a bottle (16 oz - 2 L, as desired; if you use a small bottle, you might want to use less of the key ingredients); funnel or butter knife; balloon; 3/4 cup white vinegar; 2 tbsp. baking soda

What to do:  Transfer the baking soda into the balloon using a funnel or the butter knife.  Add the vinegar to the bottle.  Carefully attach the balloon to the top of the bottle without letting any of the baking soda fall into the vinegar.  Once the balloon is securely attached, tip the baking soda into the vinegar and watch as the reaction proceeds.  Vigorous bubbling can be seen in the bottle as the balloon fills with gas. 

What happened?  What you saw was a rapid chemical reaction.  Baking soda (sodium bicarbonate) is a base and vinegar (5% acetic acid) is an acid.  When this acid and base are mixed, they react to form water, a salt, and carbon dioxide (the gas).  The carbon dioxide builds up pressure in the bottle and inflates the balloon.  Try different amounts of vinegar and baking soda to see what combinations create the most gas.  Record the amounts of ingredients you use and your observations (you can record how big the balloon is by measuring its circumference with a measuring tape...or a piece of string and a yard stick).  Try keeping a science notebook for this and other cool experiments.  That way, you'll always remember what you did, so that you can show off for your friends.  For teachers, this activity can be used as part of a lesson on chemical change, stoichiometry, acids & bases, or many other topics.

We recommend this activity for elementary to middle school students.  If necessary, have your parents help you measure the ingredients and attach the balloon.  Thanks to Sabra Ramirez of U.T. Arlington for submitting this activity to DISCUS.  Sabra credits "Exploring Creation with General Science" by Dr. Jay L. Wile for the preparation and demonstration of this activity.