Liquids and solids expand with increasing temperature because the kinetic energy of a body’s atoms and molecules increases. Explain why some materials shrink with increasing temperature.

An object's kinetic energy is the energy it has as a result of its motion. It is the amount of work required to accelerate a body of a given mass from rest to a certain velocity. The body keeps its kinetic energy gained during acceleration unless its speed changes.

Liquids and solids expand with a rise in temperature. The volume or length of the material will undergo expansion with increasing temperature. The expanded length and volume are calculated as follows:

\(\begin{aligned}\Delta L &= \alpha L\Delta T\\\Delta V &= \beta V\Delta T\end{aligned}\)

Here, \(\Delta L\) is the change in length, \(\alpha \) is the coefficient of thermal expansion, \(L\) is the initial length and \(\Delta T\) is the change in temperature, \(\Delta V\) is the change in volume, \(\beta \) is the coefficient of volume expansion and \(V\) is the initial volume.

As temperature increases, the kinetic energy of the molecules in the material increases, which causes the material to expand. But there is an exception in the case of water at a certain range of temperature. The density of water increases as the temperature rises from \(0{\rm{ }}^\circ {\rm{C}}\) to \({\rm{4 }}^\circ {\rm{C}}\). That means the volume decreases with a rise in temperature. That is why some materials shrink when temperatures rise.

Therefore, with a rise in temperature, some materials shrink due to an increase in density with increasing temperature.