Science Glossary YR 8 Earth And Space

Rock

A relatively hard, naturally occurring solid, generally made up of two or more minerals.

Mineral

(in rocks) a naturally occurring inorganic solid with a neatly ordered crystal structure and characteristic composition.

Magma

Extremely hot liquid or semi-liquid rock formed under the surface of Earth

Lava

Hot, molten rock that is expelled during a volcanic eruption

Igneous Rock

A type of rock formed when molten materials (magma or lava) cool and solidify.

Extrusive Rock

Igneous rocks that form when lava cools above the Earth’s surface

Intrusive Rocks

Igneous rocks that form when magma cools below the Earth’s surface

Sedimentary Rocks

Rocks formed from sediments deposited by water, wind or ice. The sediments are cemented together in layers, under pressure.

Sediments

Material broken down by weathering and erosion that is moved by wind or water and collects in layers.

Metamorphic Rocks

Rock formed from another rock that has been under great heat or pressure or both.

Erosion

The wearing away and removal of soil and rock by natural elements.

Weathering

Is the breaking down (physical) or dissolving (chemical) of rocks and minerals on Earth’s surfaces.