The little ball lifts the big ball - a string connecting a large and small ball passes through a tube. When the tube is whirled around, the small ball moves out, lifting the large ball.
Get both balls out - a tube is arranged so that balls fall into pockets at its ends. It is impossible to get both balls into their pockets by tilting the tube around, but if the tube is rotated, both balls move into their pockets.
Various devices fit on the variable speed rotator below:
A mass extends a spring allowing measurement of the centripetal force.
Two balls move out on rods extending a spring to measure centripetal force.
Four balls move out on semicircular wires.
Spherical shape becomes oblate when rotated.
A spinning circular chain forced off a disc by means of a stick, retains its circular shape as it rolls rapidly along the floor.
A strap of spring steel is pivoted from the center of a platform on a rotating turntable. The strap has a nail in its end so that as it falls from a standing position, it impales itself on the periphery of the platform. When the turntable is not rotating, the strap falls normally to a marked position. But when the turntable is rotating, as the strap falls the turntable continues to rotate, and the Coriolis "force" causes the strap to impale itself somewhat behind the previous mark.
This device consists of a tethered ball floating in a jar of glycerin. To establish its operation, hold it in front of you, and begin rapidly walking across the lecture hall. The ball will move forward in the direction of your acceleration at first, and then return to the vertical position as your velocity becomes constant. When you stop walking, the ball will move back towards you showing a deceleration.
Now that you have demonstrated that the ball moves in the direction of acceleration, place the device on a turntable and start it rotating. The ball will move inward showing the radially inward uniform circular acceleration.
Put a liter or two of water into the bucket. Slosh a little out on the floor to show there is water in the bucket. Then swing it in a circle around your head.
"I like to have the students 'participate' in the demonstrations, so I'll walk up into the middle of the audience to swing the bucket around. See, it's not hard! No problem at all keeping the water in! Now let see how slow I can swing it and still keep the water in!"
Swing a tray with wine glass
For a more dramatic demonstration of uniform circular motion, fill wine glass half full of water and place it on a tray with three nylon ropes connected to it. Then swing the tray around. Stopping is a bit tricky so make sure to practice beforehand. This demo really holds the students' attention and excites them - especially if the glass breaks!