what changes in the structure of an object that allows something to permanently bend (i.e folding paper)
In: Physics
Probably late to the game, but gonna try a proper maybe… ELI7?
If you zoom in smaller and smaller things are made of billions of tiny atoms that are basically little balls that are stuck together. When 2 atoms are stuck together we say they’re bonded. The sticking is a bit like how magnets stick together – they’re attracted to each other, but you can still pull them apart, breaking the bond. Atoms stick themselves together into large structures, and sometimes these structures make even bigger structures – like how a chocolate bar is made of collections of chocolate that’s bonded to rice crispies etc.. For solid objects in order to stay the same shape, the atoms can’t move around – the bonds stay the same… Unless…
If you push hard enough, just like pulling magnets hard enough, you can break the bonds and start to move the atoms around. If after you stop pushing the atoms, they can’t move back to where they were before, then the material will permanently change shape.
In the specific case of paper, atoms make molecules called proteins, that form weak bonds to other proteins and these form fibres that in turn bond together with weak bonds and that makes paper! Folding paper in half, some fibres will slide over eachother in order to change the shape, but they can’t slide back, so the shape change is permanent.
Elastic deformation i.e. when it springs back is a little more complicated as things like rubber achieve it in a different way to metal for example.
Feel free to ask any questions / query stuff.
E: just to add some credibility to my answer, I have a Masters in Materials Science.
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