The properties of expansion and contraction of materials due to temperature changes are used in various applications in daily life. Here are a few examples:

• Bimetallic Strips in Thermostats:

  Bimetallic strips, made of two different metals with different coefficients of thermal expansion, are used in thermostats. When the temperature changes, the two metals expand or contract at different rates, causing the strip to bend. This bending is used to control a switch that turns heating or cooling systems on or off.

• Expansion Joints in Bridges and Roads:

  Bridges and roads are built with expansion joints to accommodate the expansion and contraction of the materials due to temperature changes. These joints prevent the structures from cracking or buckling under stress.

• Tightening Jar Lids:

  When a jar lid is stuck, running it under hot water can help loosen it. The heat causes the metal lid to expand slightly, making it easier to twist open.

• Hot Air Balloons:

  Hot air balloons use the principle of thermal expansion to achieve lift. Heating the air inside the balloon causes it to expand, decreasing its density compared to the surrounding air, which creates buoyancy.

• Thermometers:

  Traditional liquid-in-glass thermometers use the expansion and contraction of a liquid (like mercury or alcohol) to measure temperature. As the temperature rises, the liquid expands and rises in the tube, indicating the temperature on a scale.