Physical changes means the change in substances that nothing new is created or observed. Chemical changes is just the opposite, where 2 or more substances chemically reacted together and something new is formed.
Physical changes include:
Melting ice. When ice is melted into water, the substance is still same as they're in ice. It's just that the state of matter has changed.
Cutting wood into pieces. Wood is cut smaller, but they're still wood, same substances and molecules inside.
Chemical changes include:
Putting metals in acid. For example, you put a piece of zinc into a test tube with hydrochloric acid, a new gas is formed. It's hydrogen.
Rusting. When certain metals are exposed to air, it can easily be reacted with oxygen and water which caused rust on the surface of the metal.
