Joseph Priestley first made nitrous oxide in 1772 and called it dephlogisticated nitrous air. In 1794 Thomas Beddoes and James Watt built a machine to produce it, and in 1800 Humphry Davy found it dulled the pain of an erupting wisdom tooth, suggested it for surgery, and named it laughing gas. Fashionable laughing gas parties followed, and more than 40 years passed before dentist Horace Wells used it for an extraction in 1844, only to be mocked when a patient cried out at Massachusetts General Hospital. Gardner Quincy Colton later used it on tens of thousands of patients without a fatality.

This episode explains how the gas acts on NMDA, GABA, and opioid pathways and why it leaves the body so quickly. Above about 300 degrees Celsius it becomes a powerful oxidizer, which powered the Luftwaffe’s GM-1 system, drag racing, and SpaceShipOne. As food additive E942 it whips cream, and as a cheap party drug it causes hypoxia and B12 related nerve damage. It is also the third most important greenhouse gas, 273 times as potent as carbon dioxide, and a leading cause of ozone loss.

• Joseph Clover’s 1876 inhaler that moved patients from nitrous oxide to ether
• Why racing nitrous is laced with sulfur dioxide
• Adiabatic heating and how a contaminated line can detonate a tank
• The 2024 galaxy gas trend and why canisters hold no oxygen
• How fertilized soil microbes drive the human share of emissions