ecl@mtgzz.UUCP (e.c.leeper) (10/22/85)
Expanding/contracting hole: When a ring won't come off your finger, you stick your hand under hot water. A ring is a sort of boundary condition of a hole in a piece of metal. Therfore, the hole expands when the metal is heated. Evelyn C. Leeper ...ihnp4!mtgzz!ecl
levy@ttrdc.UUCP (Daniel R. Levy) (10/23/85)
In article <1294@mtgzz.UUCP>, ecl@mtgzz.UUCP (e.c.leeper) writes: >Expanding/contracting hole: When a ring won't come off your finger, you stick >your hand under hot water. A ring is a sort of boundary condition of a hole in >a piece of metal. Therfore, the hole expands when the metal is heated. > Evelyn C. Leeper Gee, I think that could make your hand swell more than it would expand the ring :-). At tolerable temperatures, the effect is negligible on the metal. If this works, I'd attribute this to the lubrication of the wet skin more than the expansion of the ring. [Of course this has nothing to do with the puzzle!] Maybe for a better example, when a mechanic wants to take the starter gear ring off of an engine flywheel, he heats the whole thing, then perhaps cools the flywheel itself as with ice or dry ice. This produces enough gap that the ring slips off. And when piston pins are installed in piston rods, the ends of the rods (with holes in them) are heated very hot to expand them enough to let the pins be slipped in. When the rods cool, they grip the pins. Or if you must stick to the household for examples, a trick to get the lids off of jars if they are stuck is to run scalding hot water over the tops. If you twist quickly after that, they are easier to free. Of course it's not precisely a "hole" (it is covered on one end) but it's a similar idea, the hollow of a hollow metal part becoming larger when the part itself expands. -- ------------------------------- Disclaimer: The views contained herein are | dan levy | yvel nad | my own and are not at all those of my em- | an engihacker @ | ployer or the administrator of any computer | at&t computer systems division | upon which I may hack. | skokie, illinois | -------------------------------- Path: ..!ihnp4!ttrdc!levy