Question

explain why a metal bar expands when it is heated​

Answer 1

When a material is heated, the kinetic energy of that material increases and its atoms and molecules move about more. This means that each atom will take up more space due to its movement so the material will expand. ... Some metals expand more than others due to differences in the forces between the atoms / molecules.

Answer 2

When a material is heated, the kinetic energy of that material increases and its atoms and molecules move about more. This means that each atom will take up more space due to its movement so the material will expand. ... Some metals expand more than others due to differences in the forces between the atoms / molecules