PURPOSE: To show that a paraboloid of revolution is formed water is spins about an axis of rotation.
DESCRIPTION: A tupperware container is filled with water and placed atop a turntable platter. The filament of an unfrosted light bulb is carefully postioned above the water. The bulb filament is placed at the focal point of the lens. Note that the focal point of the water parabola is variable with the speed of rotation. When the water is made to rotate its surface forms a parabola and the image of the filament is formed onto the ceiling or a onto a screen.
EQUIPMENT: Motor and control, variac for the bulb stored in general use. Platter and clear bulb stored in the vault.
SETUP NOTES: This is a touchy set up!! Tweek it carefully and move the
table slowly so the alignment is not screwed up! The alignment of the focal
point for the filament and the distance to the viewing screen and the motor speed must all
be determined by trial and error. a camera can be placed at the viewing screen or
the ceiling can be used as the screen.