Question 2: When a block with a hole in it is heated, why does not material around the hole expand into the hole and make it small?
When heat is given to a body, it expands and when it is cooled, it contracts. By heating the substance, the kinetic energy of the atoms and molecules of the substance increases. The molecules then vibrate more vigorously with bigger amplitudes. The result is an expansion in the volume of the substance.
The linear expansion in the length of the substance is given by the equation;
ΔL = α LO ΔT
α = coefficient of linear expansion
Lo = Original length
ΔT = Change in temperature
When a block with a hole in it is heated, the expansion occurs in all dimensions of the block including the material of the hole. Thus, the molecules around the hole are pulled outward and an increase in the size of the hole is observed.