Oxygen (O – Atomic number 8) is certainly something we couldn’t live without – or in fact couldn’t live at all if the concentrations in the atmosphere were much more or less. But I guess if the levels had fluctuated more or been different then we wouldn’t have evolved quite the way we did.
I found it much easier to concentrate on what Oxygen does to things as subjects for my photographs – is consumed when things burn – oxidises things, such as creating rust on iron, and is given off by the process of photosynthesis – from plants both in and under oceans – though not too deep as the process also requires light.
Industrially Oxygen is produced mostly by fractional distillation of liquefied air, with some being produced by passing over molecular sieves which absorb the nitrogen. Main uses are the production of steel, and in the chemical industry for production of materials going into plastics and fabrics. And of course life support. Hospitals, divers, submariners and spacemen. Oxygen is not used for blowing up the bags that fall at you in airplanes – but the oxygen is still flowing…
It always seems strange talking about discovering something that was there all the time (like America for example) but understanding the components of air and isolating the individual elements I think is a tangible discovery. Two people are credited with Oxygen’s discovery – the Swede Carl Wilhelm Scheele (first) and England’s Joseph Priestley (first to publish) – although Antoine Lavoisier (and his wife) had a big part too in understanding what they had found.
The isotopes of Oxygen – atomic weight 16, 17 and 18 – and their relative abundance and the fact that water containing these isotopes evaporates at different rates – which is also temperature dependant has helped with both dating and identifying temperature fluctuations in the past – by analysis of ice cores.