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The Rest Is Science
The Rest Is Science

Why Do We Like Staring Into Fire?

September 27, 2026 • 59m

Summary

⏱️ 11 min read

Overview

Michael Stevens and Hannah Fry explore the fascinating nature of fire, from its chemical composition to its profound impact on human evolution and society. They discuss how fire is not a single substance but a complex chemical reaction, examine humanity's ancient relationship with flames, and draw surprising parallels between sitting around a campfire and modern social media consumption, arguing that fire served as humanity's original 'soft fascination' and social gathering point.

What Fire Actually Is: Chemistry and the Fire Triangle

Fire isn't a single substance like gold or water—it's a complex chemical reaction called combustion. The episode begins with exploring the fire triangle (fuel, heat, oxygen) and introduces a fourth element that creates the 'fire tetrahedron.' Different parts of a flame contain different states of matter: vaporized gases near the wick, blue chemiluminescent reactions where radicals meet oxygen, and orange-glowing solid soot particles suspended in gas higher up in the flame.

  • Fire is a chemical reaction (combustion) rather than a single state of matter, requiring fuel, heat, and oxygen
  • The fire tetrahedron adds a fourth point: the chemical reaction itself, which can be interrupted to extinguish fires
  • Different flame colors indicate different processes: blue from chemiluminescence, orange/red from thermally glowing soot particles
  • Blowing out a candle works by disrupting the fuel source (vaporized wax stream), not primarily by cooling
" Fire is the great-grandmother of social media. "
" We don't say, oh, that's bluba. We don't need to give it one noun. We say that it's a process. It's a thing that's happening. We've got bubbles of gas and we've got the vinegar and the baking soda mixing and then there's some water being produced, whatever. And everyone leaves it at that. But fire. We don't see it as a verb rather than a noun. "

Fire's Birthday: The History of Combustion on Earth

Fire hasn't always existed on Earth. For the first 2 billion years of our planet's existence, there was no fire because there wasn't enough oxygen in the atmosphere. Life had to evolve first, with early algae and bacteria producing oxygen as waste, before combustion became possible. The earliest evidence of wildfires dates to 420 million years ago in Wales, while the earliest evidence of humans deliberately making fire comes from Neanderthals in Suffolk about 400,000 years ago.

  • Fire couldn't exist on Earth until life created free oxygen in the atmosphere over 2 billion years ago
  • The earliest evidence of wildfire was found in Wales 420 million years ago
  • Neanderthals in Suffolk were making fire deliberately 400,000 years ago using iron pyrite
  • Earlier evidence shows opportunistic fire use by Homo erectus in Israel at least 1 million years ago
" There was a time before wildfires of any kind could even happen. Obviously, there was a time before there were plants on the dry land, but you need to have free oxygen. Those radicals need something to react with. Well, they need oxygen to react with to produce what we call fire. "
" So there were living things on Earth before there was fire. "

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