Hooked on Science: Cold balloon, warm balloon

What happens when you placed a balloon filled with air outside in a temperature below freezing?

Materials

* Two 12-inch balloons

Instructions

STEP 1: Blow up two 12-inch balloons to exactly the same size.

STEP 2: Leave one balloon inside and take the other balloon outside when the temperature drops below freezing.

STEP 3: Wait several hours and check on both balloons. Bring the cold balloon inside. What happened several minutes later?

Explanation

When air is cooled it contracts and takes up less space. Therefore, when you placed the balloon outside in a temperature below freezing the air cooled and the balloon became smaller. When you brought the cold balloon back inside the air inside the balloon, warmed and expanding making the balloon bigger. The size of the balloon inside should not change.

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