Try this trick at home: blow up a balloon inside an empty bottle

Put a round balloon inside a 2-liter bottle. Then take a deep breath and blow it up.
Did it work? Why not?

Try it again and put a straw in the opening next to the balloon. See if you can fill the bottle!

What’s going on? The balloon won't inflate much the first time because the bottle is already filled with air. There's no room for the balloon to expand inside the bottle. However, when you use the straw, the air molecules in the bottle have an exit. Try plugging the straw once the balloon is inflated to see what happens.

Science is alive and strong at Fernwood. We will have our annual science fair 26 April 2013. Come visit with us at the ice cream social and learn more about science at Fernwood!