What are the evidences of physical changes?

Your question is not very specific so it is quite difficult to answer. Do you mean physical changes that occur during chemistry or physics or the physical changes that a young person experiences when they go through puberty? Below are two possible answers to your question.

• Chemistry and physics

In terms of matter, a physical change is when the physical form of something actually changes. This could be done in three main ways. The matter could change shape. The matter could change state for example, it could be a liquid which evaporates into a gas, it could be a liquid that freezes into a solid or a solid that melts into a liquid. And finally the matter could change size by either becoming larger or smaller.

• Male physical changes during puberty

There are several physical changes that boys will experience during puberty. For example, a boy's scrotum will grow larger and hang lower rather than being up tight inside the body. This is to accommodate more sperm as the boy enters the fertile period of his life. Boys will also start to develop pubic hair which usually comes in stages. In the later stages it will grow up towards the navel and across the upper inner thighs. They may also start to develop facial hair and chest hair and their voice will become deeper.

• Female physical changes during puberty

The first physical change that girls will experience during puberty is their breasts growing. The exact time when breasts will develop varies from girl to girl. They will also start to grow pubic and under arm hair. Around the age of 13 (this is the average age) a girl will start to menstruate. Although periods may be irregular for the first year, they will eventually level out into monthly cycles. The girl's body will also start to change as they develop hips and a waist.