PURPOSE: To illustrate the behavior of a liquid accelerometer accelerating down an inclined plane.

DESCRIPTION: When the liquid accelerometer is accelerated, as in the case of the photograph at the left above, the liquid moves in the direction opposite to the acceleration, because of its inertia. When it is held motionless on an incline, the liquid moves toward the downhill side. Q: What will happen to the liquid when the accelerometer is allowed to accelerate down the incline? A: It will line up with the surface of the water parallel to the inclined plane. This can be seen in the photograph below and by an mpeg video accessed by clicking your mouse on the photograph.

SUGGESTIONS: Ask your students to vote on what will happen before performing the experiment: Will the water move toward the front (downhill), move toward the rear (as in the flat case), or line up parallel to the incline?

See Question of the Week #49 for information on using this demonstration to enhance class involvement.

REFERENCES: (PIRA 1G20.70)

EQUIPMENT: Accelerometer with incline, as photographed.

SETUP TIME: 5 min.