Lesson 2 - What do plants eat?

Activity: Weighing Air

Our balloons did not go down to show that air has weight. Any suggestions?

This one is definitely tricky! The key to making this activity work is having the balloons inflated to their maximum capacity without popping (this is so the gas in the balloons will be at maximum compression.) We ask teachers to check the balloon diameter (listed on the package) and inflate the balloons to the circumference that matches that diameter.

Another factor to consider is whether you are using latex-free or standard balloons. The most common latex-free balloons are mylar, but they don't compress the air, which is absolutely necessary for this activity to work.

If you can’t use latex, beach balls are a great alternative option! Try inflating a beach ball, weighing it with a primitive balanced postal scale, and comparing that with the weight of an un-inflated beach ball. By comparison, a fully inflated balloon is 2 or 3 grams heavier than an un-inflated balloon, weighed on a primitive balance postal scale.