Actually Jenn's Got It Now
Well in the 5 months since my last post, Jenn has landed in Kindle nirvana and that's that. On another front, I've noticed that more and more textbooks can be purchased electronically instead of in print. That's probably a good thing - the price cut is compelling and maybe 7'th graders won't be carrying 100 lb backbacks to school any more. And tomorrow, Apple unveils their 'major new product' which is rumored to be some form of tablet. The Kindle and its spinoffs are of course personal computers in disguise, and Apple and MS missed this one big. It's a little more embarrassing for Apple (hey I can say that - loyal customer of 15 years - scary to think how much money I have spent on Macs) who have tried to monopolize the business of defining new tech categories. Apple is hoping to redefine the reader/tablet category and they just might do that.
But all of that is tech mumbo jumbo. Jenn informed me that our blog gets hit a lot by people looking for the optimal method to shoot a rubber band. I guess I probably gave that away in an earlier post... Every year I challenge my students to a rubber band duel which is fun. There are the well known tricks, like aiming at a 45 degree angle to the ground and positioning the far end of the band on your finger tip so that it doesn't strike your finger as it launches.
But first, a little fun with a rubber band. Find one where the band has some width, that will make this easier. Briefly touch the band to your lip (quickly). Your lips are very sensitive to temperature. Now stretch it suddenly and test it against your lip. Did it get warmer or cooler? Now hold the band stretched for a few moments (15-30 seconds should be plenty) so that it adjusts back to room temperature. Check it with your lip, then suddenly relax the band and check it against your lips. Did it warm or cool?
You can reverse this. Heat a rubber band - does it contract or stretch? Your intuition says it should stretch, but in fact heating a rubber band causes it to contract. Putting all of this together, you can amaze your friends with a rubber band heat engine (use a lamp as the source of heating) if you have the patience to put it together. Here are some youtube links that pulled it off:
link 1: no frills vid
link 2: nice construction; tries to trick you with the direction of rotation
Still wondering if I should give away the rubber band trick again. Hmmm...