Courses: Astr1, Astr2, Astr4, P1, P3, P13, P4, P14
A spandex sheet stretched over a frame. One can place a lead ball in the center to create a well, or place a foam ball on a rod underneath to create a mountain. One can also place a foam block underneath to create a ridge. One can roll balls on the diaphragm, or place an arrow on it, to demonstrate gravity or to show the direction of an electric field.
Setup: Place clips on one corner, then the opposite corner (diagonally across), then the last two corners. Next place one clip in the middle of each side; then continue dividing the spaces in half, working on opposite sides, back and forth, to keep the tension even all around.
