Coefficient of thermal expansion

Imagine that you have a toy car whose length changes when it gets hot or cold. When it's hot, the car becomes longer and when it's cold, the car becomes shorter. This change in length is called expansion and contraction.

The coefficient of thermal expansion is a way to measure how much a material will expand or contract when its temperature changes. It tells us how much the material will grow or shrink for every degree that its temperature changes.

For example, let's say we have two materials: metal and plastic. The metal has a higher coefficient of thermal expansion than plastic, which means it will expand and contract more than the plastic when they are both heated or cooled. This is because the metal's atoms are closer together and have less space to move around when they're heated up, causing them to push against each other and expand.

Another important thing to note is that if you heat up or cool down a material too quickly, it can cause it to expand or contract too quickly and possibly break or damage it. This is why it's important to be careful when working with materials that have a high coefficient of thermal expansion.

Overall, the coefficient of thermal expansion is a way to measure how much a material changes in size when its temperature changes. It's important to know when working with different materials to avoid any potential damage or problems.