Centrifugal Escape: Motion in Two Dimensions
Marble on a Plate
PIRA Class: 1D55.12*

Purpose
To observe and understand the direction of motion of an object in revolutionary, circular motion.

Description
A marble is rolled about a paper plate in which a "slice" has been removed from. Students predict where a marble will go when it reaches the "pie slice" opening of a . ChinetÒ paper plate.
1. Roll marble around the inside of a sturdy paper plate, Discuss the motion of the marble and any forces on the marble.
2. Remove pie slice and observe direction of marble upon leaving the confines of the plate.

PEDAGOGY:
Lay out paper on counter and mark off the students' predictions for the marble's exit paths. Make sure that the paper lays very flat or there will be unwanted forces on the marble.

Equipment
2 ChinetÒ paper plates: one with and one without a "pie slice" cutout, small marble
Optional: Butcher block paper and marker