Homework Help: How to make a paper pop out ?

1. Aug 12, 2006

crays

Hi can anyone tell me how to make a paper pop out ? something like the picture here .

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2. Aug 14, 2006

Saketh

1. Get a sheet of paper.
2. Draw approximately 8 parallel lines perpendicular to the length of the sheet of paper.
3. At each line, fold the paper, alternating the direction of the fold ("accordion" style).
4. Put the paper on the ground such that all folds are stacked on top of one another.
5. Let go - the paper will pop out, as long as you did not crease the folds too much.

3. Aug 15, 2006

crays

lol sorry , my explanation skill and english is not that good . I mean , it would pop up like rubber , some force that pushes it up .

4. Aug 16, 2006

jasc15

Paper is not very elastic, but if you try what saketh said, and dont fold the paper too much, then it might work. folding the paper too much will deform the paper too far beyond its limited elastic range.

5. Aug 16, 2006

Saketh

If you crease the folds too much, then the paper will be unable to exert a significant restorative force. Picture the paper as a thin slice of wood. If you bend the wood, it will exert a restorative force against the bending force. If the bending force exceeds a certain critical limit, the wood will break and the restorative force goes to zero. Similarly, creasing the paper too much will "break" it.

After doing what I said in my post above, you will find that the paper will be able to push light things upwards. Don't ask me how to theoretically calculate the restorative force - empirical calculation is the way to go.