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No. 102: Nov-Dec 1995

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Sour grapes!

Darn! Just when we find an amusing anomaly, someone comes along and deanomalizes it. Remember the rice grains in SF#100* that sank in a glass of "fizzy" lemonade, then rose to the surface only to sink and rise again -- over and over? Well, this phenomenon is hardly new and has a good explanation. We quote from a book first published in 1925. Here, a grape and soda water are employed:

"A grape is not wetted by water, and so when it is put into the tumbler it sinks to the bottom of the soda water, where it collects bubbles at a great rate. Soon it is covered over with a sheet of bubbles that look like seed-pearls, and these bring it by their buoyancy to the surface. The grape is not much heavier than the water, and does not require much to lift it. At the surface the grape parts with some of its bubbles, which burst into the open air, and this goes on until it sinks again, only to collect a few more bubbles and once more be made buoyant. The process will repeat itself continually for many minutes until the soda water is 'dead.'"

(Bragg, William; On the Nature of Things, p. 109, Garden City, 1950. Cr. A. Mebane)

*SF#100 = Science Frontiers #100.

From Science Frontiers #102 Nov-Dec 1995. 1995-2000 William R. Corliss