Small pieces or bits that make up matter.

A change that results in the formation of new chemical substances.

The temperature at which a liquid turns into a gas.

The temperature at which a solid becomes a liquid.

A mixture where one substance is dissolved in another.

• A substance made up of two or more different types of atoms chemically bonded together.

A push or pull applied to an object.

The resistance that one surface or object encounters when moving over another.

A measure of the amount of matter in an object, typically measured in grams or kilograms.

• The natural environment in which an organism lives.

A material that allows heat or electricity to pass through it easily.

Energy from a source that cannot be replaced after it is used, such as fossil fuels.

A natural feature of the Earth's surface, such as mountains, valleys, or plains.

The process by which soil and rock are removed from one location and transported to another.

Small particles of rocks or soil.

A closed path through which an electric current flows or may flow.

• A material that does not allow heat or electricity to pass through easily.

The continuous movement of water on, above, and below the surface of the Earth.

The green pigment found in plants that is responsible for photosynthesis.