Answer: if you are talking about the body then increased hormones as physical changes with growing in sexual parts and for guys increase in with muscles and growing in breast.
If it was of a change in physical properties. as of natural in universe then it would be melting, transition to different states of matter.
Step-by-step explanation:
When everyone gets of age they grow and mature and these kind of changes happen
The reason for that would be of the change of strength, change of durability, changes to crystal form, textural change, shape, size, color, volume and density, These are some examples of physicals changes