Thermal expansion refers to the tendency of matter, such as solids, liquids, and gases, to change in size, volume, or shape in response to changes in temperature. When a substance is heated, its particles gain kinetic energy and start vibrating more rapidly, causing them to occupy more space. This increase in volume or size due to temperature change is known as thermal expansion.
To prove that L=L0(1+αΔT)L = L_0(1 + alpha Delta T)L=L0(1+αΔT) is not equal to ΔTDelta TΔT, where LLL is the final length, L0L_0L0 is the initial length, αalphaα is the coefficient of linear expansion, and ΔTDelta TΔT is the change in temperature, we can perform a simple experiment.
Consider a solid rod with an initial length L0L_0L0 at an initial temperature T0T_0T0. We heat the rod by increasing its temperature to T0+ΔTT_0 + Delta TT0+ΔT. If the equation L=L0(1+αΔT)L = L_0(1 + alpha Delta T)L=L0(1+αΔT) holds true, the change in length ΔLDelta LΔL should be equal to αL0ΔTalpha L_0 Delta Tα<span class=