Geology and Astronomy Vocabulary 6th grade semester 2

These are flashcard that can help you review science (geology and astronomy)!

Geology

A branch of science that deals with how the earth formed, its structures & composition, & the types of processes acting on it.

Weathering

The process by which rock materials are broken down by physical & chemical processes.

Sediment

Fragments of weathered rock.

Agent of Change

Factors that contribute to the breakdown of rocks into sediment.

Physical weathering

Weathering caused by the mechanical breakdown of rocks into smaller pieces.

Chemical weathering

Weathering caused by the breakdown of rocks as a result of chemical reactions.

Erosion

Process by which wind, water, ice, or gravity transport weathered materials.

Deposition

When the eroded materials are dropped or laid down.

Mineral

A naturally occurring and usually inorganic solid.

The Rock Cycle

Each of the three main types of rock (igneous, sedimentary, & metamorphic) & the processes, over geologic time, through which each of these rock types can change into another.

Crystal

The structure & shape that a mineral will take.

Magma

Molten rock inside Earth.

Lava

Molten rock at Earth's surface.

Igneous rock

Rock that forms from melted rock below ground or above ground.

Intrusive

The type of igneous rock that forms when magma cools inside Earth’s crust.

Extrusive

The type of igneous rock that forms from lava cooling on Earth’s surface.

Sedimentary rock

When sediments are compacted or cemented together by new minerals.

Metamorphic rock

Rock that has been changed due to intense heat and pressure deep inside the Earth’s crust.

Fossil

The traces or remains of organisms from long ago that have been preserved in rock.

Continental Shelf

Edge of a continent that is just underwater.

Continental Drift

The theory that Earth’s crust is moving around over the course of geologic time.

Pangea

The supercontinent that existed from 300-200 million years ago.

Sea-floor spreading

Process by which Earth’s oceans formed (especially the Atlantic Ocean) after the breakup of Pangea.

Rift Valley

Forms as two of Earth’s plates move away from each other; areas with lots of volcanic activity.

Linear sea

The narrow body of water that forms as two plates pull apart, and salt water fills in the space.

Mid-ocean ridge

Elevated ridge that forms on the ocean floor because newly formed rock is warmer & therefore less dense.

Plate tectonics

The theory that explains how large pieces of Earth’s outermost layer called tectonic plates move and change shape.

Subduction

The process of one tectonic plate sliding under another tectonic plate.

Deep ocean trenches

Deepest valleys on Earth.

Lithosphere

Brittle, rigid, solid portion of the Earth made up of the uppermost mantle and crust.

Asthenosphere

The top portion of the mantle just under the Lithosphere.

Solar Noon

The time of day when the sun reaches its highest point in the sky.

Horizon

Point where the Earth’s surface appears to meet the sky.

Rotation

Spinning on an imaginary line called the axis.

Revolution

The movement of one celestial body around another.

Polaris

The star in the sky which the north pole seems to be pointing towards.

Phase

The change in the sunlit area of one celestial body, as seen from another celestial body.

Waxing

The part of the moon we see is getting larger.

Waning

The part of the moon we see is getting smaller.

Eclipse

Occurs when the shadow of one celestial body falls on another.

Lunar eclipse

When the shadow of Earth is cast upon the moon.

Solar eclipse

When the shadow of the moon is cast upon the Earth.

Syzygy

An alignment especially of the moon with the sun.

Umbra

The darkest, smaller part of a shadow created by an object during an eclipse.

Penumbra

The lighter, larger shadow created by an object during an eclipse.

Seasons

Divisions of the year associated with particular weather patterns and daylight hours.

Angle of Separation

Measurement of an object’s position relative to the horizon.

Solstice

The two days of the year when Earth’s axis is tilted either directly towards or away from the Sun, Jun 21 or Dec 21.

Equinox

The two days of the year when the North Pole is not tilted towards or away from the Sun, equal day and night hours; Mar 21 and Sept 22.

Solar Nebula

The spinning disk of dust and gas that formed the solar system.

Accretion

The process of two or more rocks combining to form a larger rock.

Transform

One tectonic plate sliding beside another tectonic plate.

Divergent

Two tectonic plates moving away from each other.

Convergent

Two tectonic plates moving toward each other.