Entertaining and educational at the same time - bound to be some tidbits here to get students intersted in a few physics topics.

Here's an excerpt relating to the absurd number of people who fall, run, or jump through glass windows in action movies and escape without a scratch:

"Saying that shards of broken glass are razor sharp is an understatement. A shattered window contains thousands of incredibly sharp edges and dagger-like points. It takes almost no force for one of these points or edges to cause a laceration. However, people in movies routinely jump through plate glass windows without receiving a single scratch.

Broken glass has at least two mechanisms for slashing a person diving through a window: its weight and its inertia. First, large heavy shards of glass can fall like guillotines, slicing off body parts. Second, when a person jumps or, even worse, drives a motorcycle through a window, the shards of glass tend to stay in place due to their inertia. The only way to move them is to apply a force. If the person's body provides this force by pushing on the edge of a piece of glass, it can slice right through clothing, skin, and flesh. In the real world, jumping or driving through a plate glass window would be suicidal."

http://www.intuitor.com/moviephysics/

Mike

-- Michael Gatton (mgatton@vzavenue.net), October 14, 2003