Physics of the Bed of Nails Demo

This is a physics video taken about 10 years ago (1999-2000 school year) of me during my very first performance of the Bed of Nails demonstration. My assistant, Ms. G, is wielding the sledgehammer. Since that time I've done the demonstration approximately 35-40 times, and I've never received any serious injury - but THIS IS A DANGEROUS FEAT AND SHOULD NOT BE ATTEMPTED WITHOUT PROPER SUPERVISION!

The reasons why I am not injured are many - due to the large number of nails on each bed, both my weight and the force of impact of the hammer are distributed over a large number of sharp points. As a result, the pressure at any one nail tip isn't enough to break the skin or cut me. In addition, the concrete block is very massive, so because of its high inertia it won't allow the upper bed of nails to move much during impact. Lastly, the kinetic energy of the hammer goes into breaking the concrete block, so very little of that energy is transferred into me.

So there you have it, there is NO mysticism, "mind-over-matter", or anything supernatural involved in this demonstration, just good physics!

For more information on the physics of the Bed of Nails and other interesting physical feats, check out this article at the Skeptical Inquirer: http://www.csicop.org/si/9911/willey.html

Check out my personal blog, The Skeptical Teacher:
http://skepticalteacher.wordpress.com

Category:

Education

Tags:

• physics
• bed of nails
• demonstration
• skeptic
• skepticism
• teaching
• education

[SkepticMM]

Competition, perhaps? Spread the link around and more viewers will show up ;)

[kingbobnjoe]

Fake and gay.

[jordandissolved]

Now that was boring!!!

[nutzw1]

You're the teacher?

[linkboy00000000]

Awesome teacher :L

[PtheRich2]

My teacher did this but he just had the video to show us

[gatoradeee]

" In addition, the concrete block is very massive, so because of its high inertia it won't allow the upper bed of nails to move much during impact."

can you explain that to me a little further?

[paulnord]

You should stack a couple of bricks up there. It's much safer that way.

[mathewnjappallil]

I wonder why such a good video is lacking viewers?