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| Thread ID: 23254 | 2002-08-11 06:34:00 | How do I repeat a calculation 1000 times | Vince (406) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 70176 | 2002-08-11 06:34:00 | Many years ago a school teacher posed the question, as a curiosity only. "If you take a sheet of film 1 thousandth of an inch thick and fold it in half 1 thousand times, how thick will the folded sheet be?" It is of course physically impossible, but the answer will change your perspective a little. My teacher thought the answer was on the order of 100 miles, but he was wrong by a factor of a trillion or so. I solved the question years ago, the hard way, and forgot the answer! It was millions of lightyears I think. Can someone tell me how to use my computer to calculate it? Thanks in advance. Vince |
Vince (406) | ||
| 70177 | 2002-08-11 06:42:00 | Wouldn't the answer be (1x2^1000)/1000 ? | Elwin Way (229) | ||
| 70178 | 2002-08-11 06:46:00 | That's right Elwin, a computer is not needed. Dont forget to put in the units, inches :) | Terry Porritt (14) | ||
| 70179 | 2002-08-11 06:46:00 | (2^1000)/1000 sounds right to me..... it works out at about 1x10^298 |
robsonde (120) | ||
| 70180 | 2002-08-11 06:50:00 | As a matter of interest, how many times can you fold a sheet of paper in half (meaning fold once = double thickness, fold twice = 4 x thickness...) The answer is about 7 only .... try it! |
godfather (25) | ||
| 70181 | 2002-08-11 07:04:00 | Also whats interesting Godfather, is that the maximum number of folds is not very much dependent on paper size either. | Terry Porritt (14) | ||
| 70182 | 2002-08-11 07:20:00 | It's also just as hard with tissues as well. | -=JM=- (16) | ||
| 70183 | 2002-08-11 08:53:00 | hmmm - 2.7x10^293km! The no. of times you can fold a peice of paper is dependent on two factors - the thickness of the paper and, its ability to stretch. The outer side of the folded paper must be able to stretch (and the inner side compress) to allow the paper to fold in half, and thickness helps only slightly. Paper - very hard to get more than 7. Other materials can be folded slightly more, but not by much. G P |
Graham Petrie (449) | ||
| 70184 | 2002-08-11 13:31:00 | If you could remove the word "fold" from the question, and instead cut the paper in half, you would be able to go further. But even then, starting with a piece of paper .001" thick, and 100 sq. inches, after 10 folds the pile would be more than half-an-inch thick, but only 0.2 sq.in. in area. I think that shows why "folding" would very quickly become out of the question. After 17 iterations, the pile would be 65" high, but hard to work with because of its small area (.0015 sq.in or .04"x.04" square) After 30 iterations, the pile would be more than 8 miles high, but so small in area that it would be invisible to the naked eye. The results after 1000 iterations are meaningless - light would take billions of years to travel from one end to the other. |
pporritt (819) | ||
| 70185 | 2002-08-12 04:30:00 | This is just an extreme version of the very old one: the reward of 1 grain of corn on the first square of the chessboard, two grains, four grains ... Exponentials ... |
Graham L (2) | ||
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