The Skeptical Teacher

Musings of a science teacher & skeptic in an age of woo.

Walking Barefoot on Broken Glass – Not Paranormal, Just Physics

Posted by mattusmaximus on March 14, 2010

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!

5 Responses to “Walking Barefoot on Broken Glass – Not Paranormal, Just Physics”

  1. Matt said

    As someone who has been running barefoot for a few years, people sometimes ask me, “What about glass?” For some reason, it’s never been a problem. However, I would still be very squeamish about walking through a big pile of broken glass.

    Well done.

  2. […] on this blog that, whether you’re talking about breaking boards, laying on beds of nails, or walking barefoot on glass shards, such amazing physical feats have absolutely nothing to this chi stuff, but I can do so no […]

  3. Mammon Gospel said

    you can’t fool me! you’ve invented an anti-gravity machine! but i hold the patents on the idea of antigravity! my lawyers will be contacting you!

  4. […] Glasswalking – This is just a blog post and video of why it is that walking barefoot on broken glass […]

  5. FIAT LUX said

    Thanks for explaining the how in that. A former street performer used this trick and said that was just physics. But that had me scratching my head on how. It made sense that it wasn’t any “oo-la-la” formulated mind game, but I still didn’t quite get it until now.


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