While at Skepchicamp 2010, one of the woo-busting physics demonstrations I performed was that of walking barefoot on broken glass shards. Here’s a close up of the action…
This is a standard carnival trick, also used by various New Age gurus to display their supposed mystical, paranormal, or supernatural powers to their gullible followers. Sorry folks, no woo is required to explain this (pardon the pun) impressive feat. This is some video shot by a few of my students earlier this year when we were discussing the physics of pressure…
It can all be explained with a simple understanding of basic physics: by walking flat-footed on the shards, I spread my body weight evenly over the entire surface area of my feet, which means that I’m touching a large number of glass shards at once. Thus, since my weight is distributed over so many points, the pressure (force per unit area) at any one of those points is so small that it isn’t enough to stab or cut through my skin.
Thus, through a simple application of Occam’s Razor, we can conclude that nothing paranormal is required to explain what’s going on, just good physics!
The Skeptical Teacher 