## Sunday, November 28, 2010

### Multiple exposure photography

I'm dipping a toe into multiple exposure photography.

As is so often the case in such undertakings, I have no idea what I'm doing, but cannot resist the potential for grooviness.

I just started tinkering with this nonsense the day before Turkey Break. The image-compression trickery is built into my pocketable digicam, the Casio EX-FH100. My Fujifilm HS10 can do it, too. But the FH100 is much handier.

Click the image to see more of what I've been able to get so far.

## Sunday, November 07, 2010

Original post here. A BMW motorcycle is used to pull the tablecloth from under a banquet table with full formal setting. Go back and watch the videoclip.

Mythbusters story web clips: Tablecloth Chaos.

Executive Summary: Jamie was able to clear the tablecloth from under the banquet table setting. But only when he was able to get his custom bike to high speed before pulling the tablecloth. This required that the bike accelerate a distance with considerable slack in the rope.

The trick, as performed in the BMW ad, is not physics-ly possible. You simply cannot start from rest and jump to cloth-pulling speed on a motorcycle.

Shame on you, BMW.

Hat tip to Dan Burns via the AP Physics EDG.

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.

### Dark Side of the Laptop

If you're keen to show some attitude on your laptop (or iPad, or cell phone), you might consider MusicSkins.

I installed a Dark Side of the Moon decal on my MacBook Pro 15" and I gotta say, it rocks! It matches the wall outside my classroom.

And you know you're on to something when someone in the 2AM crowd at Denny's shouts out a compliment for your laptop. Oh, the decal is quite opaque: it blocks the light of the Apple logo. The #1 tech company in the known universe will have to muddle through without mobile advertising from me.