Sunday, November 07, 2010

Newton's Cradle telekinesis

My telekinesis training is moving apace quite nicely. I recently shared this result with my colleagues in the NCNAAPT.



The initial shock of the demonstration was somewhat subdued when I showed them an overhead view.



When I showed them the view from the static-cam, they no longer believed my claim of telekinesis.



O science! Must you take all the fun out of bogus claims?

I've developed a series of demonstrations involving the use of a rotational platform. The first two involve the use of Pasco's Visual Accelerometer. We do these demos in Physics 1. The third involves the Newton's Cradle. We save this one for AP Physics 2.

Demo 1: Will It Go 'Round in Circles?
What is the direction of acceleration for an object in circular motion? Tangential? Radial? Inward? Outward? Note: our students have completed the "PhyzLab: Going Through the Motions" prior to this demonstration, so they know the function of the Visual Accelerometer.

Demo 2: Will It Go 'Round in Even More Circles?
What happens to the magnitude of acceleration as the object is set farther and farther from the axis of rotation? The increase in radius suggests decreased acceleration. The increase in speed suggests increased acceleration. The Visual Accelerometer settles the matter.

Demo 3: Will It Go 'Round in Advanced Circles?
What happens when a Newton's Cradle is taken for a spin on a rotational platform? You already know the answer. In AP Physics 2, we develop an equation for the angle of the cord and interpret the equation.

And of course, a shout out to the legendary Billy Preston for the title.

2 comments:

Dave Traversi said...

Dean- You've no doubt seen this video-

http://www.archive.org/details/frames_of_reference

It made me think of your telekinetic abilities at frame 17:08.

Quite a classic from start to finish.

GMC said...

When the platform is not rotating, are all balls touching each other?