Question

Explain why a metal bar expands when it is heated?

Answer 1

Answer:

When metal bar is heated it expands because as the temperature increases the atoms starts to vibrate. This vibration of atoms leads to the separation of atoms inside the metals. This separation is not enough to break the bonds between atoms but make them slightly apart. This is known as thermal expansion.

Answer 2

Answer:

When a metal bar is heated, it's particles speed up. As the temperature rises, the vibrations of the particles take up more space and the bar expands slightly in all directions.