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BOB HIRSHON (host):
Peanut butter and magnets. I’m Bob Hirshon and this is Science Update.
The technology behind bullet trains may be used on food. Harvard University chemist George Whitesides and his colleagues are using magnetic levitation, or mag-lev, to calculate a food’s density – a measure of quality and value. It’s done in a small, fluid-filled chamber with magnets on the top and bottom. The magnets push against a suspended food sample, as gravity pulls it down.
GEORGE WHITESIDES (Harvard University):
You can see you have a kind of balance of two forces, a magnetic force which is repulsive, and a gravitational force which is attractive in the down direction. And these two balance at a certain height and that height is related to the density.
The technique could cheaply gauge the fat content of milk, the protein content of peanut butter, the quality of cooking oils, and more. I’m Bob Hirshon, for AAAS, the science society.