Changes in Matter: Physical or Chemical

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. Examples include changes in state (like melting or freezing) and changes in shape or size.

A chemical change is a change that results in the formation of new chemical substances. It involves a chemical reaction and the rearrangement of atoms. Examples include rusting iron and burning wood.

Physical change.

When water boils, it undergoes a physical change from liquid to gas (steam) without changing its chemical composition.

Water freezing into ice is a physical change where the state of water changes from liquid to solid.

Breaking a plate is a physical change because it alters the shape of the plate but does not change its chemical composition.

Mixing baking soda and vinegar results in a chemical change, producing carbon dioxide gas and new substances.

Many physical changes can be reversed, such as freezing and melting, but some may not be reversible, like breaking a glass.

Chemical changes are often not reversible by simple physical means, as they involve the formation of new substances.

An example of a physical change in nature is the melting of ice in the sun.