“How to Change a Rock” Vocabulary and Information

Cycle – a repeated sequence of events

Cementation - one of the processes that work together to turn sediment into sedimentary rock.Mineral-laden water percolates through sediment. The spaces are gradually filled by minerals precipitating from the water, binding the grains together.

Rock – relatively hard material composed of two or more minerals that have been cemented, squeezed, heated, melted and/or cooled. Rocks are divided into three basic types; igneous, sedimentary and metamorphic, depending upon how they were formed.

Deposit – earth material that has been laid down by the action of wind, water, ice, or volcanic eruption

Mineral – a basic earth material. A mineral is a part of a rock that cannot physically be broken down any further.

Molten – made liquid by heat. Molten rock that flows out onto the Earth’s surface is called lava.

Lava - magma that reaches the Earth’s surface through a volcanic eruption. When cooled and solidified, lava forms extrusive (volcanic) igneous rock.

Sedimentary rock – A layered rock formed by deposits of sediment. Most are under water. 70% of all rock is sedimentary rock.

Sediments - loose pieces of rock or minerals, deposited by wind, water, and ice into layers. If they get buried under pressure and cementation, they become sedimentary rock.

Metamorphic rock – rocks that have been changed chemically, physically or both by intense heat and pressure. “Meta” is a Greek word that means “many”. “Morphic” means “to change shape.”

Igneous rock - rock formed when molten rock (magma) has cooled and hardened. Igneous is a Greek word that means “fire”. The most common rock found on the earth’s surface is basalt.

Erosion –the wearing away of earth materials by water, wind, or ice.

Weathering - surface processes that decompose rocks. No movement is involved in weathering. Chemical weathering involves a chemical change in at least some of the minerals within a rock. Mechanical weathering involves physically breaking rocks into fragments without changing the chemical make-up of the minerals within it. Mechanical weathering includes processes such as the freezing and expansion of water the fills cracks in a rock.

Geologist – a person who studies the Earth and Earth’s materials.

Geology—Geology is the science and study of the earth and its life, especially as recorded in rocks.

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