The biggest component in any human, filling 61 per cent of available space, is oxygen. We need, for instance, just twenty atoms of cobalt and thirty of chromium for every 999,999,999½ atoms of everything else.

Who would have thought that we would be incomplete without some molybdenum inside us, or vanadium, manganese, tin and copper? Our requirements for some of these, it must be said, are surpassingly modest and are measured in parts per million or even parts per billion. Six of these – carbon, oxygen, hydrogen, nitrogen, calcium and phosphorus – account for 99.1 per cent of what makes us, but much of the rest is a bit unexpected. (Cumberbatch was the guest director of the festival that year and was, conveniently, a typically-sized human.)Īltogether, according to RSC calculations, fifty-nine elements are needed to construct a human being. Perhaps the most respectable and comprehensive attempt of recent years was made by the Royal Society of Chemistry when, as part of the 2013 Cambridge Science Festival, it calculated how much it would cost to assemble all the elements necessary to build the actor Benedict Cumberbatch. Many authorities (for which possibly read ‘science undergraduates who don’t have a date on a Friday’) have tried at various times, mostly for purposes of amusement, to compute how much it would cost in materials to build a human. The question is: was it true? Are we really worth so little? It was such a spectacularly humbling revelation that it has stayed with me all these years. It may have been $2.97 or $13.50, but it was certainly very little even in 1960s money, and I remember being astounded at the thought that you could make a slouched and pimply thing such as me for practically nothing.

Long ago, when I was a junior high school student in America, I remember being taught by a biology teacher that all the chemicals that make up a human body could be bought in a hardware store for $5 or something like that.

Bill bryson the body