Hooked on Science: Balloon in a bottle

Have you ever tried to blow up a balloon inside a bottle? It's easy if you use science.

Materials

* Two balloon

* Two empty water bottles

* Thumbtack

Instructions

STEP 1: Insert a balloon into one of the empty water bottles and pull the neck of the balloon over the outside of the bottle.

STEP 2: Place your mouth over the opening of the bottle and attempt to inflate the balloon.

STEP 3: Using the thumbtack, force four evenly spaced holes around the bottom of the other water bottle.

STEP 4: Insert the balloon into the bottle with the holes and pull the neck of the balloon over the outside of the bottle.

STEP 5: Place your mouth over the opening of the bottle with the holes and attempt to inflate the balloon.

Explanation

When you inserted the balloon into the empty water bottle, air is trapped inside the bottle. As you attempt to inflate the balloon, the trapped air inside the bottle keeps the balloon from inflating, proving air takes up space. The small holes evenly spaced around the bottom of the other water bottle, allows the trapped air inside the bottle to escape. This allows the balloon to inflate.

Jason Lindsey is a science outreach educator with Hooked on Science. Check out his websitehookedonscience.org for webcasts and experiments.