Mechanics: Seat of Nails

PIRA Class: 1K30.15

Purpose:
To demonstrate the difference between force and pressure.

Description:
A volunteer or the instructor can safely sit on a seat of nails with no discomfort.

Optional: Inflate a balloon and push it into the seat of nails showing it does not pop then push the balloon into the single nail to show it pops.

SAFETY: Best done when wearing jeans or other rugged pants. If not wearing jeans, lay the cloth over the nails to avoid scrapes. You want to sit on the nails "all at once" rather than one leg at a time. If the nail bed is placed on a stool this can be done comfortably (there is space on the edge of the board to your hands and lower yourself).

VARIATION: Setup a 7x7 array of Dixie Cups and lay the pressure poster board across the top. Have a student step onto the board near the center. With the weight distributed across cups, the cups should support the person without crumpling.

Equipment:
Seat of nails and individual nail blocks, optional: balloon, Dixie cups and board

Location:
Shelf 121 (seat of nails and individual nail blocks), balloons are on shelf 164