Explain why water should never be used to put out oil or petrol fires.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Nature of Oil and Water**:
- Oil and petrol are less dense than water, which means they will float on top of water when mixed together.

2. **Behavior of Water When Poured on Oil Fire**:
- When water is poured onto an oil or petrol fire, it does not mix with the burning oil. Instead, the water sinks to the bottom because it is heavier than the oil.

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