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UWM's Saldin highlights 'the path of least time' in March Science Bag

Newton takes center stage at this month's UWM Science Bag, and not just for his observations about apple trees
Newton takes center stage at this month's UWM Science Bag, and not just for his observations about apple trees
Photo by Sean Gallup/Getty Images

March 2014 UWM Science Bag


The shortest path between two points is a straight line. But that's not always the fastest path. Distinguished Professor of Physics Dilano Saldin shares examples of this paradox in this month's UWM Science Bag: The Path of Least Time and Other Optimal Paths.

Saldin has put together a true physics geek's Science Bag. He beams as he retells anecdotes from the life of Isaac Newton and draws on abstract diagrams with lots of arrows to explain concepts. If you aren't used to reading these types of diagrams, you may get a little lost in his explanations.

But an interesting subtext emerges from Saldin's stories. Newton, he says, was so effective defending his status as undisputed champion of mathematics that no one challenged or tried to improve on his work for centuries. This leads to a certain irony. Newton's contributions to mathematics were founded on questioning ideas held true since Plato and Aristotle. It's unfortunate, then, that much of his own work was treated as infallible in subsequent generations rather than progressed with similar zeal.

Saldin has an easy task engaging kids since physics always boasts the best toys. Lasers, pendulums, bicycle wheels and large track slides elicit ready volunteers, although the professor fails to utilize his eager assistants in more involved ways than holding props steady.

If you're bringing kids, you may have to help them with some of Saldin's vocabulary. He explains it, and some simple definitions are provided below:

Cycloid – any curve made by tracing a point on a circle as it rolls

Tautochrone – from Greek roots tauto (same) + chronos (time), a path on which two objects from different starting points reach the same end point in the same amount of time

Brachistochrone – from the Greek roots brachisto (shortest) + chronos (time), the fastest path

From an adult perspective, it would be nice to hear Saldin speak more on his own expertise in biophysics, which makes up only a small portion of his talk but which is easily the most fascinating to older listeners.

The final presentation of Paths of Least Time and Other Optimal Paths is Friday, March 28 at 8:00 pm in room 137 of the UWM Physics Building. The event is free and open to the public.

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