Jeffrey LewisScience is Fun!

After reading much of Ann Finkbeiner’s The Jasons, I found myself with several people swapping stories about Dick Garwin.

Matthew Bunn had the best of the bunch, which involved Garwin explaining to him how the conservation of kinetic energy might allow a certain type of ball to return after being bounced on the floor and the underside of a table.

A few days later, Bunn received a paper in the mail entitled, “Kinematics of an Ultraelastic Rough Ball” (American Journal of Physics 37:1, January 1969, pp.88-92) by Richard L. Garwin that began:

“Angle of incidence equals angle of reflection” is a commonly quoted but, of course, not univeral result, and it is useful to demonstrate to a freshman or high school physics class that real objects exhibit behavior equally predictable but in some cases quite different. In particular, a perfectly rough ball which conserves kinetic energy behaves in such an unexpected way that it is difficult to pick up after it has bounced twice upon the floor and, more bizarre, it returns to the hand on being thrown to the floor in such a way that it bounces from the underside of the table as in Fig. 1.1

1. This was first demonstrated to me by L.W. Alvarez with a Wham-O Super Ball.

L.W. Alvarez is, of course, Nobel Prize-winning physcist Luis Alvarez.

Full text.


  1. Haninah

    Hilarious! That would have been right around when folks (including people at LANL) were putting together the first collective models of nuclear behavior, thus probably the interest in vibrational modes.

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