1D50.33 - Central Forces - Carry a Ball

Code Number:
Demo Title:
Central Forces - Carry a Ball
Forces Due To Circular Motion
Area of Study:
Wine Glass, Small Cork Ball, or Rubber Ball.

These wine glasses are also used for the 3D40.50 - Musical Goblet or Bowl demonstration.

To carry a ball without touching it you need a wine glass with a body that has a slightly larger diameter than the rim. Invert it an place it over the ball, and then move the wine glass in a circle. The ball will start to rotate around the rim inside the wine glass and then will climb up into the body of the glass. Continue the rotational motion of the glass and you can carry the ball anywhere you wish.

  • R. D. Edge, "Levitating a Marble", TPT, Vol. 24, #5, May 1986, p. 295. 
  • "M-370: Lift Ball in Bottomless Cup", DICK and RAE Physics Demo Notebook.
  • Robert Ehrlich, "G.3, Rotating a Ball Inside an Inverted Plastic Cup", Turn the World Inside Out, p. 91 - 92.
  • Martin Gardner, "Transporting an Olive", Science Tricks, p. 44.
  • Bobby Mercer, "Jar Spin", Junk Drawer Physics, IBSN 978-1-61374-920-3, p. 9 - 10.

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.