Glossary

aerosol (AIR uh sol) — mixture of droplets of liquid in a gas

atom (AT uhm) — tiny particles from which all materials are made

basalt (ba SAWLT) — type of rock formed when lava cools quickly

boiling (BOI ling) — when liquid is turning into a gas as fast as possible

boiling point (BOI ling point) — the temperature at which a liquid starts to boil

carbon dioxide (KAR buhn dye OK side) — a gas in the air that helps keep Earth warm

cloud (kloud) — small drops of water floating in the air

condensing (kuhn DENSS ing) — gas turning into liquid

crystal (KRISS tuhl) — a piece of material with sharp edges and flat surfaces

evaporating (i VAP uh rate ing) — liquid turning into gas

freezing (FREE zing) – liquid changing to a solid

freezing point (FREE zing point) — the temperature at which a liquid starts to freeze, the freezing point of a material is the same as its melting point.

gas (gass) — a substance that is invisible, easy to squash, and spreads out to fill the container that it is in

granite (GRAN it) — a type of rock that forms when magma cools slowly

humid (HYOO mid) — when there is a lot of water vapor in the air

lava (LAH vuh) — molten rock that comes out of a volcano

liquid (LIK wid) — a wet substance that you can pour

magma (MAG muh) — molten rock beneath Earth's surface

melting (MEL ting) — solid changing to a liquid

melting point (MEL ting point) — the temperature at which a solid starts to melt, the melting point of a material is the same temperature as its freezing point

microorganism (mye cro OR guh niz uhm) — a tiny living thing that can only be seen with a microscope

molecule (MOL uh kyool) — a tiny particle made from two or more atoms joined together

nitrogen (NYE truh juhn) — a gas in the air, about 78 percent of the atmosphere is nitrogen

oxygen (OK suh jun) — a gas in the air that we need to breathe, about 21 per cent of the atmosphere is oxygen.

pollution (puh LOO shuhn) — when harmful chemicals are added to the air, the ground, or the water

property (PROP ur tee) — a way of describing what something is like (for example, properties of ice are that it is hard and has a fixed shape)

solid (SOL id) — a substance that has a fixed shape and volume

state (state) — states of matter are solid, liquid, and gas

steam (steem) — water vapor formed when liquid boils

volume (VOL yuhm) — the amount of space that something takes up

water cycle (WAW tur SYE kuhl) — changes that happen to water as it evaporates from the sea, falls as rain, and then runs back into the sea

water vapor (WAW tur VAY pur) — water when it is a gas