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Expansion and contraction of a solid substance due to heat

Topics

Introduction
Experiment

Introduction:

When heat is applied to a solid, its molecules move faster and spread apart, causing the solid to expand. On the other hand, when the solid cools down, the molecules slow down and come closer, leading to contraction. This behaviour of expansion and contraction due to changes in temperature is commonly observed in metals and is important in everyday life, such as in the design of bridges, railway tracks, and thermometers.

Experiment

1. Aim: To observe how solids expand when heated and contract when cooled.

2. Requirements: metal ring, metal ball (of size that fits through the ring), and burner.

3. Procedure

Initially, verify whether the metal ball can pass through the ring at room temperature.
Now, heat the metal ball using a burner.
Try to pass the heated ball through the ring again.
Let the ball cool down, and try passing it through the ring once more.

4. Conclusion: After heating, the metal ball expands and does not pass through the ring. Once the ball cools down, it contracts and passes through the ring easily. This experiment shows that metals expand on heating and contract on cooling. Different solids may expand and contract at different rates.