MSCS Graduate Student Seminar

Fall 2000

September 8

SPEAKER: Mark Ronan
TITLE: Magic with a wineglass explained using topology and group theory
ABSTRACT: Take an object, a wineglass for example, and rotate it by 360 degrees. Imagine it attached by invisible cords to the corners of the room. After the rotation these cords will be twisted together although the wineglass itself will be back in its original state. The cords cannot be untwisted, but if you rotate the wineglass by a further 360 degrees, making 720 degrees in total, then the cords, which are now even more twisted together, can be returned to their original untwisted state without rotating the wineglass at all. This strange phenomenon is related to some elementary aspects of topology and Lie groups. There is no need to know anything about Lie groups or topology beforehand.