Turntable

Mini-Vibe
The motion of objects as they move around other moving objects is apparent throughout the universe. Several simple models can be made using everyday items.

Materials:

• Small round object (marble or bead)
• Disposable pie pan (a paper plate may be used if it has 2 to 3 cm deep sides)
• Pushpin
• Several layers of corrugated cardboard

Place the marble in the pie pan and spin the pan, keeping the marble contained within the pan. Observe the motion of the marble while the pan is moving and as it is stopped.

Push the pushpin through the center of the pie pan and then into the cardboard. (Stack the corrugated cardboard together to serve as a surface to push the pin into to protect the table top.) Quickly rotate the pie pan with the marble near the outer edge of the pan. Place the marble near the center of the pan and spin again. Observe the motions of the marble each time. Remove the pan and cut a wedge-shaped piece from one side of the pan. Repeat each trial and record the new results.

Does the marble spin or slide when the pan is spun? Does it move to the center or to the edge when spun? What path does it take when there is an opening along its path? (Does it continue to follow a curved path after it leaves the pan?)