Every flick of a lighter is a small act of chemistry that most people never think twice about. But behind that familiar spark is a remarkable element called cerium, and its party trick is one of the most dramatic on the periodic table. Cerium is pyrophoric, meaning it can ignite spontaneously when finely divided or struck. This is not a subtle chemical curiosity. It is the very property that makes modern fire-starting possible.

Cerium is the key ingredient in ferrocerium, the metallic alloy used in lighter flints and fire-starting rods around the world. Every time you flick a traditional lighter, you are scraping a small rod of cerium alloy against a rough surface. The friction shaves off tiny particles of the metal, and because cerium oxidizes so readily, those particles ignite almost instantly upon contact with air, producing the hot sparks that light the fuel. It is a beautifully simple mechanism that has remained largely unchanged for over a century.

Ferrocerium was invented in 1903 by Carl Auer von Welsbach, an Austrian chemist who had a particular knack for finding practical uses for rare earth elements. His invention quickly replaced older, less reliable methods of sparking flame, and it remains the standard today. Survivalists and outdoor enthusiasts prize ferrocerium rods because they work when wet, at high altitudes, and in freezing conditions, all situations where matches and butane lighters tend to fail.

Learn more: Episodic Table

Monday, February 9 to Sunday, February 15

The following are the shortest paths from last week:

Play Forgeous for Feb 16