daemon@decwrl.UUCP (The devil himself) (10/28/85)
Concerning the problem: Does the hole expand when the metal around the hole is heated? Try it for yourself! Here's how... [This experiment is given in the 7th grade General Science book published by D.C. Heath, 1961. I used it many times in my former junior high science teaching days to prove that metal expands when heated.] You need 2 pieces of apparatus: 1) loop of 1/4" thick metal, attached to a wooden handle so it can be held in a flame without burning yourself. 2) ball that just fits through the metal loop, attached to a wooden handle so you can hold it easily. Procedure: Holding the loop by its handle, place the metal end in a flame for a minute or so (We used a gas burner, but even a fireplace will do). Then try to fit the ball apparatus through the loop. You will find that the heated metal has expanded in all directions (including inward into the space of the hole), making the hole smaller so that the ball no longer fits through the loop. Once the loop cools off, the ball will once again be able to fit through. A M A Z I N G !
hes@ecsvax.UUCP (Henry Schaffer) (10/29/85)
> Does the hole expand when the metal around the hole is heated? > > Try it for yourself! Here's how... > > You need 2 pieces of apparatus: > 1) loop of 1/4" thick metal, attached to a wooden handle so it can > 2) ball that just fits through the metal loop, attached to a wooden > > Procedure: Holding the loop by its handle, place the metal end in a flame > do). Then try to fit the ball apparatus through the loop. You > will find that the heated metal has expanded in all directions > (including inward into the space of the hole), making the hole smaller > so that the ball no longer fits through the loop. Once the loop cools > off, the ball will once again be able to fit through. > > A M A Z I N G ! I think I remember this experiment - except that the ball was heated, and then couldn't go through the hole. --henry schaffer
tino@hou2f.UUCP (A.TINO) (10/29/85)
>Concerning the problem: > >Does the hole expand when the metal around the hole is heated? > >Try it for yourself! Here's how... > >[This experiment is given in the 7th grade General Science book published >by D.C. Heath, 1961. I used it many times in my former junior high science >teaching days to prove that metal expands when heated.] > >You need 2 pieces of apparatus: > >1) loop of 1/4" thick metal, attached to a wooden handle so it can >be held in a flame without burning yourself. > >2) ball that just fits through the metal loop, attached to a wooden >handle so you can hold it easily. > >Procedure: Holding the loop by its handle, place the metal end in a flame >for a minute or so (We used a gas burner, but even a fireplace will >do). Then try to fit the ball apparatus through the loop. You >will find that the heated metal has expanded in all directions >(including inward into the space of the hole), making the hole smaller >so that the ball no longer fits through the loop. Once the loop cools >off, the ball will once again be able to fit through. > >A M A Z I N G ! ________________________________________ That would be AMAZING if it were true. I just don't believe it!!!!! I would believe the following demo: make the ball just a little too big to fit through the metal ring when the ring is at room temperature. Now if you heat the ring, it expands --THE HOLE GETS BIGGER!!! When the ring is hot the ball passes through it easily. Al Tino
js2j@mhuxt.UUCP (sonntag) (10/31/85)
> Does the hole expand when the metal around the hole is heated? > Try it for yourself! Here's how... > [This experiment is given in the 7th grade General Science book published > by D.C. Heath, 1961. I used it many times in my former junior high science > teaching days to prove that metal expands when heated.] > > You need 2 pieces of apparatus: > 1) loop of 1/4" thick metal, attached to a wooden handle so it can > be held in a flame without burning yourself. > 2) ball that just fits through the metal loop, attached to a wooden > handle so you can hold it easily. > > Procedure: Holding the loop by its handle, place the metal end in a flame > for a minute or so (We used a gas burner, but even a fireplace will > do). Then try to fit the ball apparatus through the loop. You > will find that the heated metal has expanded in all directions > (including inward into the space of the hole), making the hole smaller > so that the ball no longer fits through the loop. Once the loop cools > off, the ball will once again be able to fit through. This from someone who used to *teach* junior high science! Apparently it's been a long time since you tried this experiment. Try it again. Or use a Xerox machine which has scaling capabilities. Draw a circle on a piece of paper. Have the Xerox machine scale it to 160% (or whatever yours does easily). Is the inside of the circle bigger? Or did the line expand, making the inside of the circle smaller? Or consider a coin. Think of an arbitrary circle on the surface of the coin. Imaging heating the coin. The circular piece inside the circle expands, right? If the (imaginary) hole in the torus-like piece outside the circle got smaller, the coin would explode, wouldn't it? Do coins do that when heated? No? So the hole must expand too, right? Right. If I ever have a kid to send through school, I guess I'll have to be very wary of the quality of science teachers they get. We've just seen proof that some science 'teachers' are ignorant of the most basic concepts. -- Jeff Sonntag ihnp4!mhuxt!js2j "What would Captain Kirk say?"