When hot water is poured on a glass plate, it breaks because of

Answer

**Step-by-Step Solution:**

1. **Understanding Glass as an Insulator:**
- Glass is a poor conductor of heat, which means it does not allow heat to transfer easily from one part to another. This property is crucial in understanding why the glass plate breaks when hot water is poured on it.

2. **Initial Contact with Hot Water:**
- When hot water is poured onto the glass plate, the surface of the glass that comes into contact with the hot water experiences a rapid increase in temperature.

3. **Thermal Expansion of the Glass:**
- As the temperature of the glass surface increases, it undergoes thermal expansion. This means that the molecules in the heated area of the glass start to move faster and require more space, causing that part of the glass to expand.

4. **Unequal Expansion:**
- However, the other parts of the glass plate (the sides not in contact with the hot water) remain at a lower temperature and do not expand. This creates a situation where one side of the glass is trying to expand while the other side is not.

5. **Resulting Stress and Breakage:**
- The difference in expansion between the hot side and the cooler side creates internal stress within the glass. When this stress exceeds the strength of the glass, it leads to cracking or breaking of the plate.

6. **Conclusion:**
- Therefore, the glass plate breaks due to unequal thermal expansion caused by the rapid heating of one side while the other side remains cool.

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