Accelerometers And Frames Of Reference
To demonstrate the direction of the acceleration in both rotational and translational coordinate systems.
Rotating jars with pingpong balls in air and water, tube with pingpong ball in water.
In each experiment the pingpong balls act as accelerometers. When the jars are rotated, the ball suspended from the bottom of the water-filled jar moves toward the direction of the acceleration, while the ball suspended from the top of the air-filled jar moves in the direction opposite the acceleration. The pingpong ball in the water-filled tube indicates the direction of the acceleration when the tube is accelerated linearly or rotated.