CORNER

Did you know that the two most biodiverse places in your home are your gut and your compost bin? If you even have a compost bin… If you do, then it’s time to join UCL’s Big Compost Experiment, says Professor Mark Miodownik. And if you don’t, then it’s definitely time to celebrate the ‘miracle’ that is compost! Katie Jarvis spoke to Mark about his work, his life – and how to save the earth

- Katie Jarvis

So the best thing about science is this, I think, as I read (mesmerised) Mark Miodownik’s books. We’re all experts without knowing it!

We all know, for instance, that gently pushing a ballpoint pen onto paper causes ink to flow. (A shopping list, a love letter, a furiously bold note on someone’s shockingly parked car.)

We all know that tipping up a ketchup bottle can be a disappointing exercise. Whereas a satisfying thwack produces tangy crimson splodges.

Or – have you ever thought about this – take cutlery. Really, we should all wince as we lift a spoon or a fork to our mouths, waiting for the dull taste of metal to hit. But we don’t. We don’t, because we know it won’t. We’ll just get melting lemon syllabub, or fluffy baked potato, unadulterated.

So, yes – we all sort of know this.

But it’s odd, really. And that oddness largely passes us by.

For the fact is – as Mark explains – the ink in a ballpoint (invented by László Bíró) is a non-Newtonian fluid. With some of these fluids, an impact causes them to act more like a solid. (Believe it or not, you could actually walk (as demonstrated once on TV) over a swimming pool full of custard.)

Others (like ketchup) become runnier when whacked. László’s ink takes the smallest of impacts to make it flow onto a page.

And stainless-steel cutlery? “…it’s the transparent protective layer of chromium oxide that makes the spoon tasteless, since your tongue never actually touches the metal and your saliva cannot react with it”. (We are, Mark points out, one of the first generations not to taste our cutlery.)