Science Vocabulary

Unit C  Chapter 7

(31 words)

atmosphere – the blanket of gases that surrounds Earth

cleavage – the tendency of a mineral to break along flat surfaces

delta – fan-shaped region formed by deposits of sediments found at the mouth of a river

deposition – the dropping off of bits of eroded rock

erosion – the picking up and carrying away of pieces of rocks

fault – a crack in Earth’s crust whose sides show evidence of motion

flood plain – land that is likely to be underwater during a flood

gem – a mineral valued for being rare and beautiful

geologist – a scientist who studies rocks to tell how they formed and to predict when an

          earthquake may occur

hardness – how well a mineral resists scratching

humus – decayed plant or animal material in soil

hydrosphere – Earth’s water, found in continents and oceans, including the fresh water in

          ice, lakes, rivers, and underground water

igneous rock – a rock formed when melted rock material cools and hardens

lava – magma that reaches Earth’s surface

lithosphere – the hard outer layer of Earth, about 100 km thick

luster – the way light bounces off a mineral’s surface

magma – hot, molten rock deep below Earth’s surface

meander – bends or s-shaped curves in a river

metamorphic rock – a rock formed under heat and pressure from another kind of rock

meteorite – a chunk of rock from space that strikes the surface of Earth or the Moon

mineral – a solid material of Earth’s crust with a definite composition

ore – a mineral containing a useful substance

pollution – any harmful substance added to Earth’s land, water, or air

rock – a naturally formed solid in the crust made up of one or more minerals

rock cycle – rocks changing from one into another in a never-ending series of processes

runoff – precipitation that flows across the land’s surface or falls into rivers and streams

sediment – pieces of material carried and deposited by water or wind

sedimentary rock – a rock made of bits of matter joined together

streak – the color of the powder left when a mineral is rubbed against a hard rough surface

watershed – area from which water is drained; region that contributes water to a river or

          river system

weathering – breaking down rocks into smaller pieces