Which tire will roll down the ski jump fastest and jump the farthest? A Formula One tire? An enormous bulldozer tire? The smallest tire? This clip from Japanese television has made the rounds in years past, but the video source disappeared. We watched it again when it reappeared on Metafilter. Gotta love the lab coats, white gloves, and the surprising last jump.
So which of these six tires would you guess makes the biggest jump? And why?
When a magnetic field moves through a conductor a current called an Eddy current is induced in the conductor due to the magnetic field’s movement. The flow of electrons in the conductor creates an opposing magnetic field to the magnet which results in damping of the magnet and causes heating inside of the conductor similar to heat buildup inside of power cords. The loss of energy used to heat up the conductor is equal to the loss of kinetic energy by the magnet.
And a note of caution if you decide to try this, these magnets are not for unsupervised children. In fact, everyone should be careful:
Neodymium magnets larger than a half inch are very strong and should be handled with extreme care since they can be dangerous. It is best to stick with neodymium magnets of quarter inch diameter or less.
Get some rubbing alcohol, white coffee filters, a few clear glasses, scissors, and a wooden spoon. Next, head outside to find leaves that are at different stages of their color change — around 10 per color. For additional info, read more about this experiment at SciAm.