A physical change is when matter changes forms but not chemical identity. A chemical change is when atoms are rearranged into new substances.
An example of a physical change is taking water and freezing it. When you defrost water (melt ice), it's still water. Even when it's frozen, it's still water. The chemical identity (H2O) is the same.
An example of a chemical change is burning something (like toast). It actually is chemically altered. You can't un-burn your toast. You can't take burnt toast crumbs and turn it back into a fresh slice of bread. You can't burn logs of wood, take the ashes and un-burn them into wood again. It's permanent.