Thursday, March 5, 2009

All matter is made of atoms.

Sorry for the large gap between posts. Our school's web filter has decided to block blogging sites. It makes it difficult for me to publish the class content online.

We started a new topic on atoms. The big idea is that everything is made of atoms. We've been learning about the kinetic molecular theory. That's a fancy way of saying that atoms are always moving and bumping into each other. When those atoms are heated, they speed up. Since they're speeding up, they move farther apart. Heat them up really quickly and you get really fast expansion as you can see below.




The molecules of air in the film canister were rapidly heated and spread out quickly. This blew the film canister into the air.

Another implication of the KMT is that molecules bump into things and cause pressure. In this picture you see a balloon in a bell jar. The vacuum pump (not pictured) removes the air from the jar. The air inside the flask remains. It is still moving around and there's pressure inside the balloon. Since the pressure inside the balloon is greater, it expands. Remember when we learned how to calculate net force? Same idea. Since the pressure is greater on the inside, it expands until it reaches equilibrium.















That's it for now. Remember that the trimester ends in two weeks. If you are unhappy with your current grade, check your portfolio and find out what you still need to learn.

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