Sunday, January 30, 2011
The Bike Tires Are Flat! Winter Science For Children
We had a couple of warm, dry, spring-like days, last week. The children were thrilled to have a chance to pull out their bikes, in the middle of the winter. But, when the temperature dropped, so did the air in their tires.
They wanted to know why colder weather made the tires go flat. Thanks to Rose Wyler's Science Fun With A Homemade Chemistry Kit, I was ready with a Sunday Science experiment, to demonstrate the answer.
The air around us, and in our bike tires, or in a balloon, is a gas, made up of fast moving, spread out, molecules.
When the gas is cooled, like in a cold garage, or in the refrigerator, or even better - the freezer...
...the molecules slow down, and compress together. So, they take up less room, and the tires go flat, or the balloon shrinks. If you're very fast, after removing the balloon from the refrigerator, you can measure the difference (as long as you measured the balloon before you put it in the cold, for comparison).
But, what's really neat, is to put a balloon in the freezer, for an hour, and then pull it out, and hold it in warm hands. You can feel it expanding, as the air warms, and the molecules spread back out.
For more fun with science, check out this week's Sunday Science link-up, at Adventures in Mommydom.
It's great to be a homeschooler.