Ever wondered why a waste-bin fills up so quickly with paper, especially if you crumple the paper into balls? And did you know that it is only possible to repeatedly fold a piece of paper six or seven times, independent of the size of the sheet that you are using? The folding problem at least is understood: since with each folding step the thickness of the paper doubles, it rapidly becomes impossible to bend the piece of paper to fold it once more.
Physicists have revealed striking similarities between the random crumpling of a piece of paper and repeated folding, explaining why your waste-bin fills up unexpectedly quick when throwing away your paper in either manner. They published their results in Physical Review Letters.
On the other hand, It appears that crumpling is very different, since it is random instead of regular. An international team of physicists including prof. Daniel Bonn from the Institute of Physics at the University of Amsterdam have discovered surprising similarities between the two compaction processes, which they published in the prestigious journal Physical Review Letters.
In the Letter, the similarities are demonstrated by combining mechanical and geometrical measurements during crumpling. A geometrical characterization of ridges in a crumpled ball of paper shows that simple folding models capture also the main features of crumpling. The analogy then allows to predict that a typical crumpled paper ball in a waste-bin consists of as much as 75% air: crumpling is a very inefficient compaction process. The reason is similar to that of the folding problem: the force necessary to crumple grows extremely rapidly with the degree of compaction.
The study explains why your waste-bin fills up so quickly when you crumple your paper: very rapidly the force necessary for further compaction becomes excessively large.
Source: University of Amsterdam