## Saturday, January 1, 2011

### Conservation of Momentum

Objects in Motion, Chapter 5 part 1, Conservation of Momentum.

I turned to a favorite book of mine, Gizmos and Gadgets, and found a bunch of activities relating to this chapter. Simple things, like giving them three coins--two pennies and a nickle--and challenging them move one penny using the other penny without them touching each other. They tried all kinds of things before finally figuring out how to use then conservation of momentum to do it.

And more complex things, like creating Newton's Cradle using marbles and an egg carton ramp. There's just something fascinating about watching spheres collide!

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We finished up building a simple momentum tower, another idea from the book. I had two 20 oz bottles filled with water. The kids tied a string between them and then attached two strings with paperclips to the first string, and then stuck modeling clay onto the paperclips. They held the bottles so the string between them was taut and then carefully swung only one of the clay suspensions. Guess what happened to the other clay swing?

### Universal Gravitation

Objects in Motion, Chapter 4, The Law of Universal Gravitation.

This chapter brings together Kepler, Galileo, and Newton, especially the first and the last.  I created a review sheet listing their laws we covered next to a picture of each of them.

All I used for this class was a white board.  I read and we discussed, using the board to draw illustrations and to write equations.  It served as a good opportunity for review as well as an opportunity to consider the information in novel circumstances.

We considered and discussed the weakness of gravity, elliptical motion, "falling around" earth, wobbling planets, Newton's cannon, and satellite rockets.  It makes for good conversation...