The modern alchemist – Air: The elixir of life (2012)

Peter Wothers

Watch the first lecture from the 2012 CHRISTMAS LECTURES series.

Peter Wother talking to a crowd of seated children during his CHRISTMAS LECTURE
Credit: Royal Institution

Lecture 1 – Air: the elixir of life

Take a deep breath. Inside your lungs is a mixture of highly reactive and incredibly stable gases. Oxygen is the most reactive constituent. When we eat it's these O2 molecules that seize electrons from our food to give our bodies the energy to live. Add a third oxygen atom and we make ozone, a gas so reactive that it's toxic if we breathe it in, but high up in the stratosphere this gas protects us from the sun's radiation. Add a carbon atom and we produce carbon dioxide, a greenhouse gas responsible for warming the planet.

Nitrogen, the most common element in air, is an unreactive gas, but a key atom in every cell in every living thing on Earth. How can we imitate nature to bring this suffocating gas alive?

Even less reactive are the Noble or inert gases. They're so stable they are the only elements that exist naturally as individual atoms – but what is it about them that make them so inert? And how can we excite these gases enough to join the chemical party?

We've come a long way from the days when alchemists thought the air was a single element, as we unravel the puzzle of how and why these compounds of oxygen hold the key to the viability of life on the planet.


When medieval alchemists staged spectacular stunts in front of royalty they never revealed the secrets of their mystical potions and fire-breathing creations. Today's chemists can perform equally impressive feats, but they do so to explain and explore the extreme frontiers of our material world. 

Watch Peter Wothers, the modern alchemist, as he unpicks the chemistry of the world around us - looking at air, water and earth - three of the original ancient Greek 'elements' that tantalised alchemists for centuries.