AAPT.org - American Association of Physics Teachers

# High School Photo Winner's Showcase

« 2012 Winners Gallery

## Bed of Nails by Jacob Michael Yoshimura

### Honorable - Contrived Category

School: Glenbard West Highschool

Teacher: Nicholas Szarsak

Pressure is defined as ?Force per unit area, where the force F is understood to be acting perpendicular to the surface area A?. This derives the equation; P=F/A, or, pressure is equal to the quotient of the force exerted, and the surface area it is pushed upon. This photo shows a rig of one hundred nails set up equidistant from each other, making a sort of ?bed of nails?. A balloon is placed on the bed of nails, and a force is pushed upon it to demonstrate that the balloon will not pop, even with a significant amount of force being applied onto it. The force acting upon the balloon is shown by the amount that the balloon deforms, as it was originally a near perfect sphere, and was formed into an ovoid, or an egg shape, rather than its natural spherical form when it was pressed down upon the nails. The force acting on the balloon is distributed over the surfaces of each of the one hundred nails, which causes the balloon to deform, and not pop, even though the nails are very sharp and pointed. If this same pressure was applied to the balloon while resting on just one nail, it would most definitely pop, as there is only the small surface area of the tip of the nail to support the balloon, and with less area of contact, less force is required in order to push the nail through the balloon.