h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

At the same time as being the common name for the group of chemicals mentioned, 'plastic(ity)' is actually a property which a material can have... some materials are plastic, others aren't. Some 'plastics' aren't, in fact, plastic.

Technically, y'see, 'plastic' is the opposite of 'elastic'. Something is plastic if, when you change its shape by force, it doesn't return to its original shape. If it *does* return to its original shape, it's elastic.

To confuse matters, *any* material, if stretched with enough force, reaches something called its 'plastic limit' - after which it acts like a plastic, that is, it won't return to its original shape when you let go of it.

Hopefully I've got all the details right here... I've just been learning about this in Physics, not two hours ago, so I've got no excuse

26199

I thought it was the 'elastic limit' that was reached when things went from elastic behaviour to plastic behaviour. If this is the case, then surely the plastic limit is when it then breaks after being streched too far

Could be, could be... it's definitley one or the other.

I'll look it up...

Yep, it's the elastic limit .

I'll be okay... I've got about a year before I have any exams on this particular topic... thankfully.

26199

Thanks for letting me know I wasn't forgeting things I did years ago!