Thermal Expansion

The video tutorial explains thermal expansion, where objects expand when heated and contract when cooled. It covers linear, area, and volume expansion, introducing coefficients of expansion for different materials. The anomalous behavior of water, which contracts when heated from 0°C to 4°C, is highlighted for its environmental significance. The expansion properties of gases are discussed, with a focus on the ideal gas law. The tutorial concludes with an example of thermal stress in steel rails, explaining why train tracks have gaps to prevent bending during temperature changes.

What happens to a metallic lid when it is exposed to heat?

• It expands and loosens.

• It contracts and becomes tighter.

• It remains unchanged.

• It melts completely.

What is the coefficient of linear expansion?

• A constant that relates the change in length of an object to temperature change.

• A measure of how much an object's volume changes with temperature.

• A constant that relates the change in mass of an object to temperature change.

• A measure of how much an object's area changes with temperature.

How does water behave between 0°C and 4°C?

• It remains at a constant volume.

• It contracts as it cools.

• It expands as it cools.

• It evaporates completely.

Why is the maximum density of water at 4°C environmentally important?

• It causes lakes to freeze completely.

• It allows aquatic life to survive in winter.

• It makes water evaporate faster.

• It prevents water from freezing at all.

How does the coefficient of volume expansion for gases compare to that for liquids?

• It is less dependent on temperature.

• It is more dependent on temperature.

• It is not affected by temperature.

• It is the same for both.

What is the relationship between the coefficient of linear expansion and volume expansion for a cube?

• Volume expansion is three times the linear expansion.

• Volume expansion is half the linear expansion.

• Volume expansion is equal to the linear expansion.

• Volume expansion is unrelated to linear expansion.

Why do train tracks have gaps between them?

• To reduce noise when trains pass.

• To make maintenance easier.

• To prevent bending due to thermal expansion in summer.

• To allow for contraction during winter.