Question

Give one application of expansion and contraction each in solids, liquids and gases.

Answer 1

Solids, liquids, and gases expand on heating and contract on cooling in most cases.

Solids –

• Expansion – There are gaps left intentionally when two rail tracks are joined because the metal tracks expand during the summer season due to heat and contract when they are subjected to cold weather. If no gaps are left in the tracks the expanding tracks will bend and can cause accidents.
• Contraction – The electric cables when installed on the poles are left loose and hanging so that they can contract in a cold environment and do not break.

Liquids –

• Expansion – When mercury is heated it expands and this property of mercury is used in thermometers to measure the temperature.
• Contraction – When the temperature drops the mercury also contracts and hence shows a decrease in temperature.

Gases –

• Expansion – When gases are heated they expand very rapidly and start to rise, this property of gases is used to fly the hot air balloons.
• Contraction – Gases generally occupy a large area so they are cooled and converted into liquids so that they can be transported easily. This technique is used to transport natural gas from source to destination.