Teacher lies on a bed of nails in lesson

Step on the business end of a nail and surely you're headed to the emergency room with a painful puncture wound.

Lay down on a bed of nails and let someone take a sledgehammer to the cinder block on your chest and surely you're a physics teacher.

As any science teacher worth his weight in lesson plans will tell you, it's the amount of pressure you put on the nail that gives it the power to puncture. Put all your weight on one point? Yow. Spread your weight out across hundreds of points? Wow.

But teachers like Lucas Pang know you can talk about pressure and force all you want and some kids are still going to doubt what you're saying. Some kids need to be shown. With a sledgehammer.

Pang, a teacher at Waubonsie Valley High School in Aurora, recently put himself under the sledgehammer to prove his, um, point.

With fellow physics teacher David Sieh wielding the hardware, Pang sandwiched himself between two beds of nails and allowed two cinder blocks to be stacked over his chest.

Sieh lifted the hammer and brought it down to shatter the blocks.

When the dust cleared and the top bed of nails was lifted off, students could see Pang bore no resemblance to Swiss cheese.

Just as the teachers had predicted, the force from the sledgehammer spread out among all the nails and wasn't enough at even one point to send Pang to see the school nurse.

Clearly, he'd made his point.