Gaussian Gun Activity

A student in my advanced laboratory class has begun investigating the energetics of the 'Gaussian Gun'. Here is one of many YouTube videos on the device:

http://www.youtube.com/watch?v=ZqZKh0NGqco

I think this system provides a nice simple context in which to think about magnetic energy. The video could be used as an elicitation question. Where does the extra kinetic energy come from? The simplicity of this equipment naturally lends itself to student exploration of the feel and sound of the energy associated with interacting balls and magnets.

I am also intrigued by the ideas expressed in the attached comments on YouTube:

'Can you make a channel so the balls fall back down and feeds back in so that it can repeat continously? And, if so, what is keeping you from putting a little windmill contraption as the ball shoots out to convert a little bit of the linear energy into rotational energy? If you could do this, wouldn't that qualify as a 'free-energy' device, as you would harvest a bit of the energy gain?'

'I could bring back ball with no problem. But there is already one ball attracted to the magnet. So first this ball should be removed and then effect could be repeated. But it takes a lot of energy to remove the ball that was attracted in the first round.
The big question is: Is the kinetic energy of the ball that rolls away bigger than energy needed to remove the ball that was attracted to the magnet?'

3 Sisters Cattle Company

This past weekend while cycling on Whidbey Island I stopped in at 3 Sisters Cattle Company.

http://www.3sistersbeef.com/

This is a beautiful farm near Penn Cove where they raise 100% grass fed cattle. I spent quite a while talking with the owners, Ron and Shelly Muzzall about raising cattle. It was immediately obvious to me that they are a wonderful resource for information and practical knowledge about the energetics of beef production. I am hoping to send a team of students up there in the fall to interview the Muzzall's about these issues. I envision this as part of a class project which will involve preparing a meal on an energy budget for homeless youth in the U-district.

It's always easy to have big dreams about courses that are month away.

The prospect of using video for myself

Every time I analyze video carefully with colleagues I am impressed by how differently the action in a classroom appears when I am free to not think about my own influence on the classroom. When I am talking to students in class a considerable portion of my attention is on my next move. Watching video without the pressure of a next move allows me to devote my entire understanding to the words and unspoken gestures of an individual student. I think that this makes it especially easy to see that student as a resourceful, intelligent agent.

Video of SPU students being light

Several of the students spontaneously recognized that when the car cooled off the thermal energy would leave the car but could remain as thermal energy in the surrounding air. Thinking about the IR camera led students to decide that at least some of the energy leaving the car must arrive at the camera as IR. The students were undecided on what form the energy should take when it arrived at the camera.

Hunter was deliberately encouraging students to focus on specific questions which were presented by the energy theater. What form of energy is it that leaves the car and travels to camera? What form does this energy take when it arrives at the camera?

Hunter moved the group quickly passed other questions. What are three mechanisms of thermal energy leaving the car?

Hunter also choose not to focus on some questions. What is the difference between conduction and convection? Does IR leave in all directions, or just toward the camera?