PURPOSE: To show that air is viscous.

DESCRIPTION: A large thin disc is suspended above a copper plate mounted on a rotator. As the plate is rotated, the thin disc begins to rotate slowly in the same direction, because of drag caused by the viscosity of the air.

SUGGESTIONS:

REFERENCES: (PIRA 2C30.10)

EQUIPMENT: Rotator (from D1 cabinet), Barlowe's disc (from K1 cabinet), thread, cardboard disc and stand.

SETUP TIME: 10 min.