Physical and Chemical Changes

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. Examples include melting, freezing, and hammering wood.

A chemical change is a change that results in the formation of new chemical substances. Examples include burning wood, rusting iron, and photosynthesis.

Melting ice is a physical change.

Rusting of iron is a chemical change.

During a physical change, the form of a substance changes, but its chemical identity remains the same.

During a chemical change, the substances involved undergo a transformation that changes their chemical structure, resulting in new substances.

Cooking an egg is a chemical change.

Dissolving sugar in water is a physical change.

Photosynthesis in plants is an example of a chemical change in nature.

Breaking a glass is a physical change.