Hooked on Science: Warm and cool balloon

Most of us have inflated a balloon, but have you ever noticed the difference in temperature between an inflated balloon and a deflated balloon?

Materials

* Balloon

Instructions

STEP 1: Inflate the balloon and then quickly feel the outside of the balloon.

STEP 2: Deflate the balloon and then quickly feel the outside of the balloon.

Explanation

The inflated balloon feels warm, while the deflated balloon feels cool. The temperature drops as the air is released through the small opening of the balloon. Energy is used to force the air through the small opening. The removal of this energy results in a drop in temperature.

Jason Lindsey is a science outreach educator with Hooked on Science. Check out his website www.hookedonscience.org for webcasts and experiments that might get you hooked on science. Send him your science questions at jlindseyhookedonscience.com. More science experiments can be found at www.semissourian.com.