Class 10/21/08

The first topic of today's class was buoyancy effects. We watched a simulation that had a weight hanging from a scale. Below that was a beaker of water on a scale. The weight hanging from the scale weighed 10 grams, and the beaker of water on the scale weighed 200 grams. We lowered the weight into the beaker of water. As the weight lowered into the water, the scale holding the weight got less, and the scale holding the beaker weighed more. This is due to the amount of water that was being displaced as the weight went into the beaker. Finally, the weight sunk to the bottom of the beaker and the scale on top held no weight, but the scale holding the beaker weighed 210 grams. This was a very interesting simulation.
Then we did a short lab about force. We put a ping pong ball in a class with a funnel. We blew on the opposite end of the funnel from us and the egg jumped into the cup that was right next to it. We determined that the egg jumped out of the first glass because of the air pressure we excerted upon it. The air travels underneath the egg causing it to pop up and jump into the other glass. We determined that you cannot place the glasses very far apart for the ping pong ball to jump into it. The farther apart the glasses, the harder you have to blow. We also determined that if you blow on the near side of the egg, the egg pops up and down but doesnt switch cups. This is because the force is at equilibrium. In conclusion, the force is in direct proportion to the length.
After the lab, our groups got together to finish outlining our midterm projects. Our group is meeting later on this week to test our project.