Question

What is the difference between dilations and the other transformations?

Answer 1

All these appear to be physic phenomena because they do not change the composition of the matter. 

However, while rotations, translations and reflexions do not alter the volume of the matter, dilation does increase the volume. 

Dilation, by definition, is an enlargement of the matter and directly opposed to contraction. For example, heat dilates the matter, while colds contract it. The exception to this is that when water becomes ice due to cold, it increases in volume.