Lesson: Not just a regular Pendulum                                                                Dave Matthews






Script for Wilberforce Pendulum:


            T)   How did you  release the spring?

S)    We just dropped it from the top.

T)    Did you push it?

S)    No.

T)    Is that like the pendulum from yesterday?

S)    No. That one swung back and forth.

T)    Does this one swing?

S)    Yes. The weight does.   But it spins like a clock.

T)    How far have you gotten it to spin like a clock?  3 oÕclockÉ6 oÕclock

S)    Just to 3. Is that okay?

T)    Yes. Do you want it to spin farther?

S)    Yes.

T)    How would you do that?  More or less weight?

S)    I donÕt know.

T)    Work it through with me. If you put more weight on it what do imagine happening?

S)    It will spin farther.

T)    So how it will spin with no weight?

S)    It doesnÕt spin as much. We tried it when you were giving instructions.

T)    Okay.  Try it with different weights to prove your point.  IÕll come back and check your data.



Script for Coupled Pendulum:


S)    Why does each of the start swinging only if wee move one?

T)    Tell me exactly what you saw happening?

S)    We followed the directions by swing the string pendulum and the other one started moving.

T)    Show me.

S)    Like this.

T)    Where are the energy transfers?

S)    Here the bob has the most potential right before you drop it.

T)    Then what?

S)  It has the most kinetic energy as it bottoms out on the arc. Like yesterday.

T) After that what happens?

S)    It Kinetic energy goes back into making potential energy.

T)    Making potential energy?  It makes energy from nothing but scratch?

S) No from, from all the kinetic it has coming from this part of the swing.

T)  Oh. Every ounce of energy is put into the potential then?

S)    Yeah.

T)    Are you sure?

S) I think so.

T) That doesnÕt sound as if you are going bet on it.

S) I guess that some energy would go into friction with the air.

T) ThatÕs better thinking. What else do you see about the set-up?

S)    The cable.  Energy passes through there and starts the other moving.

T)    How?

S) The motion of the arm.