1A fire isn't a thing — it's an eater
Fire is fuel and air eating each other
A flame isn't an object sitting there. It's a reaction that has to keep being fed. Two ideas:
Burning eats two things
Fuel + a gas in the air crash together and turn into heat and light. That crashing-together is the flame. Stop feeding it and there's nothing left to crash.
The gas it eats is oxygen
Only about a fifth of the air is oxygen — the part fire eats. The flame gulps it up, so it needs fresh air arriving all the time or it goes hungry.
2The three things a fire needs
The fire triangle
A fire needs three things all at once. Picture them as the three corners of a triangle — take any one corner away and the triangle falls apart, and so does the flame:
All three together → a flame lives. Remove any one → the flame dies.
3Your turn — feed the fire
Drag each supply and watch the flame answer
Here's a live flame with three taps feeding it: fuel, heat, and oxygen. Try turning each one down on its own. A fire is only as strong as its weakest supply — starve any single one and the whole flame shrinks.
Big, healthy flame 🔥
4Now drop the glass
Two candles, lots of wax. Cover one. 🫙
Two identical candles, both with plenty of wax to burn. You'll drop a glass jar over the one on the left and leave the right one open. Guess what happens first — then watch.
Guess before you drop the glass
Both candles have lots of wax. You seal the left one under a glass. Which goes out first — and why?