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UWRF Society of Physics Students Chapter visits 3M


October 8, 2015

On Saturday, Oct. 3, several members of the UW–River Falls Society of Physics Students Chapter attended 3M’s Super Science Saturday.

Moving from the left to right, as from the perspective of people in front of the table, one would first notice the infrared camera display. This display had a monitor, so as to display the output of the camera. At the beginning, this display was difficult to understand, since the scale would automatically adjust to the excessively hot water heater in the background; a scale on which humans are very cold in comparison. This was eventually fixed and there really wasn’t much else interesting about it. Apparently, infrared light is blocked by glass and such, so you can hide behind glass on an infrared camera. This also explains the greenhouse effect, since the infrared is heat and it cannot escape through glass.

Next up was the “rainbow glasses” display, which actually consisted of “diffraction grating glasses.” These glasses make things look rainbow-y, because they diffract the light. A red and a blue LED were supplied to show an example of light that isn’t diffracted into a rainbow. Bubbles with a light shown through them were also included and, through the glasses, one could describe them as “pixie-like.”

The bristle-bots were by far the least popular display. A vibrating motor was attached to the head of a toothbrush with a battery to make it scurry about like a cockroach. These were significantly outclassed by the much more conveniently placed cup-bots, which followed the same concept except with a customizable cup instead of a little toothbrush head.

The last, and clearly most awesome, demonstration was a re-purposed bike wheel. The tires had been replaced with a ceramic material and handles were attached, this allowed participants to hold on to the wheel while it was spun. The weighted rims would create a significant amount of angular momentum, which could then be used to demonstrate the properties of this aspect of physics. A turntable onto which the participant could step was supplied. When on the table, which was about the height of the first step of a step stool, the person could easily be spun about. In this position they would hold the wheel while one of the SPSC members spun it. The participant would then turn the wheel on its side and, by the conservation of angular momentum, begin spinning. Because that is how physics works. Several attempts were made to explain this to the small children attending the event, many of whom simply ran away in fear, likely to avoid physics courses for as long as they are able from there on.

This wheel also had a rope through one of the handles. This was to show that, due to the angular momentum, the wheel would remain upright when spinning. To explain a real-life example of where this is important: when riding a bike it is easier to balance when at higher speeds.

Behind the table were several pallets left by 3M filled with miscellaneous merchandise. These were properly labeled as “free stuff,” as they were filled with free stuff. Two of these pallets contained large amounts of Scotch tape rolls. I took 15 tape rolls. I need tape sometimes, and it was free.

Trevor Hoglund is a student at UW-River Falls.