Breaking Board Paradox - Demonstration Kit

By: The Flinn Staff


Simple, yet very dramatic. A thin white pine stick is placed over the edge of a table. A sheet of tissue paper is placed over the stick and spread out on the table. When the overhanging portion of the stick is hit sharply with a hammer it breaks. The other end of the stick remains stationary and the paper is not torn. The large surface area of the tissue paper provides 15 lbs./sq. in. of pressure resisting the movement of the stick. When struck, the stick cannot withstand the pressure and breaks. Students will be amazed at the results. Enough materials are provided for 10 demonstrations.

Concepts: Air pressure, surface area, inertia.
Time Required: 20 minutes
Materials Provided: Pine boards, tissue paper.
Note: A hammer is required, but not included.