Fast Fire, Slow Rust
Two speeds of joining with oxygen.
What this lesson covers
Why it matters
A match bursts into flame in a second, while an iron gate takes months to turn rusty. Both are the same thing happening: joining with oxygen, just at very different speeds.
Predict first
Burning wood and iron slowly rusting look nothing alike. What do they actually have in common?
Both are oxidation, which means combining with oxygen. Burning is fast oxidation and rusting is slow oxidation.
- Both are substances joining with oxygen (oxidation) — correct
- Both give out bright light and lots of heat
- Both happen only when you add water
- Both give off carbon dioxide
What you do
Sort each example into fast oxidation (burning, with obvious heat and light) or slow oxidation (quiet and gradual).
Check yourself
What does oxidation mean in both burning and rusting?
Oxidation means a substance joins with oxygen. Both fast burning and slow rusting are oxidation.
Which statement best describes burning?
Burning is a fast oxidation reaction that releases energy quickly as heat and light.
Which of these is an example of slow oxidation?
Rusting of iron, respiration and food spoiling are slow oxidations, joining with oxygen gradually without a flame.
- A substance combines with oxygen — correct
- A substance combines with water
- A substance splits into smaller pieces
- A substance gives off oxygen
- It is fast oxidation that gives out heat and light — correct
- It is slow oxidation with no heat
- It happens without any oxygen
- It only happens to metals
- Iron rusting and food going stale — correct
- A firework exploding
- Striking a match
- A gas-stove flame