The increase in the volume of heated objects is called expansion, and the decrease is called contraction. If the solid substance is in the shape of a rod, it is examined as lengthening, if it is in the form of a plate, it is examined as expansion in the surface, and in objects such as spheres and cylinders, it is examined as expansion in volume. When a solid rod is heated and its temperature is increased, it is observed that its length increases #physics #expansion #explainlikeimfive #physicsmem