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By Doug Millard on

No Laughing Matter

A Scientific Lecture, 1802
Gilray's 'A Scientific Lecture', 1802, depicts Humphry Davy 'bellowing' laughing gas

What have Humphry Davy, Mike Melvill and my dentist got in common? Answer: They’ve all exploited the chemistry of nitrous oxide, popularly known as ‘laughing gas’.

Davy experimented with euphoria-inducing properties of the gas with his friends Samuel Taylor Coleridge and James Watt. Davy was working at the Pneumatic Institution, set up by Thomas Beddoes to investigate the medical properties of inhaled or ‘factitous airs’. Davy pursued his experiments – part scientific, part recreational – with his normal con brio and was fortunate not to have seriously damaged his and others’ health.

Lucy Baldwin's Analgesic Apparatus, 1955-80
Lucy Baldwin's Analgesic Apparatus, 1955-80, mixed oxygen and nitrous oxide during midwifery (Science Museum/Science & Society)

My dentist, alongside doctors and medics, has long employed nitrous oxide as an analgesic, to relax patients and as a prelude to anaesthesia.

And Mike Melvill? Well, as pilot of SpaceShipOne, the world’s first privately developed spacecraft, he depended on its ability to oxidise rocket fuel for the thrust that carried him spaceward on his pioneering sub-orbital flight of 2004.

Dobson Ozone spectrometer, 1926
Dobson Ozone spectrometer, 1926. Dobson's technique for detecting ozone led to the discovery of the ozone hole over Antartica in 1985. (Science Museum/Science & Society)

So nitrous oxide has a variety of uses but it also has a dark side. Whether produced naturally or by industrial activity it leads to ozone depletion of the upper atmosphere. This lets in more of the Sun’s harmful ultra-violet radiation which the ozone molecules normally absorb. Plus, nitrous oxide acts as a particularly effective greenhouse gas, trapping the heat re-radiated from the Earth’s surface and causing global temperature rises.

No laughing matter indeed.