Charlotte Hamilton
School of Chemistry, University of Bristol

Bone. It's hard, one the hardest components of the human body. Yet it's still got a bendy component, which is a good, because if it didn't we'd all be crumpled heaps on the floor. Also despite its hardness, bone has got a gentle, caring side. It protects all the internal organs, allowing us to crash into things on occasions without too many repercussions. It's also useful in that it allows us to do things like walking, talking and well just about everything really. Imagine life as a jellyfish, it can't be fun.

Bone is in fact living tissue, so it needs a blood supply. If you do the right things to fresh bone (namely strip away an outer layer called the periosteum, but that's getting gorey) it you can see it bleed. This living component of bone is the bendy bit. While the hard, brittle bit, is made of a mineral called hydroxyapatite.

Some weird things start happening to bones, if you take them into space, or if you put to much strain on them through exercise, or simply as you age. Lots of research goes on about bones in these conditions and ways of keeping bones healthy