• Mass, color, volume, and weight are examples of physical properties. A physical property can be observed or measured without changing the substance.

Example: you can find weight of an object by placing it on a scale.

• Melting point and boiling point are also physical properties. Melting point is the temperature at which a solid melts to form a liquid. The melting point of water is 0oC. Boiling point is the temperature at which a liquid boils to form a gas. The boiling point of water is 100oC.

• A chemical property determines how a substance will behave during a chemical reaction.

• A physical property of matter can be changed. For example, crushing an aluminum can involves a physical change. A physical change is a change of the appearance, shape, size, or texture of a substance.

• A physical change does not change the identity of a substance.

• Some examples of physical changes include melting ice (change in state), tearing a piece of paper, and breaking a pencil.

• A chemical change results in the formation of one or more new substances. Chemical changes happen all around us. They happen in your body (digestion and respiration).

• Examples: Burning (wood turns into ash and smoke), Rusting, Bleaching (bleach dissolves color), Digesting (stomach acids digest food), Photosynthesis, Cooking, Baking.

• The process by which new substances are formed is called a chemical reaction.

• There are certain signs that a chemical reaction has occurred. These signs include heat, the release of gases, change in color, and giving off light.