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8th Grade STAAR Objective 5

Terms in this set (58)

Galaxy
a large group of stars in the universe
Spiral Galaxy
galaxy that is disc-shaped with a thin disk with long arms; gas and dust rotate around the central hub of the galaxy
Elliptical Galaxy
huge galaxy that is round or oval in shape
Irregular Galaxy
huge galaxy with no regular shape
Star
huge, hot body made of different gases; radiates energy (light)
Nebula
an immense cloud of gas (mainly hydrogen) and dust in space; where stars form
Planets
nearly round objects that revolve around a star; in our solar system the planets that revolve around our Sun are; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
Sun
medium sized star; located near edge of galaxy; many thousands of times closer to Earth than any other star; provides energy that creates convection currents in atmosphere and oceans
Comet
small object made of ice with some gas, dust, and rock; a "tail" can appear as the comet revolves around the sun and is heated
Hertzsprung-Russell Diagram
organizes the family of stars into a diagram; across bottom is star's temperature and side is star's absolute magnitude; a star's temperature and color depend on how big the star is
Electromagnetic Spectrum
increasing range in frequency of electromagnetic waves; light and radio waves are used to gain information about distances and properties of objects in the universe; ex. light years used to measure distances and sizes in the universe
New Moon
moon phase that occurs when the Moon is between Earth and the Sun; the Moon cannot be seen because its lighted half is facing the Sun and its dark side faces Earth
Waxing Crescent
moon phase that comes after a new moon and before a first quarter moon; less than half of the moon is lit up on the right side
1st Quarter Moon
moon phase that comes after a waxing crescent and before a waxing gibbous; is lit up on the right half of the moon that we can see
Waxing Gibbous
moon phase that comes after a first quarter moon and before a full moon; more than half of the moon is lit up on the right side, but it isn't completely full
Full Moon
moon phase that occurs when all of the Moon's surface facing Earth reflects light; the Moon appears completely lit
Waning Gibbous
moon phase that comes after a full moon and before a third quarter moon; more than half of the moon is lit up on the left side, but it isn't completely full
3rd Quarter Moon
moon phase that comes after a waning crescent and before a waninggibbous; is lit up on the left half of the moon that we can see
Waning Crescent
moon phase that comes after a third quarter moon and before a new moon; less than half of the moon is lit up on the left side
Rotation
spin of Earth (or other Moon/planet) on its axis; takes 24 hours; causes day/night
Revolution
movement of Earth around Sun; takes 365 ¼ days; causes seasons
Solstice
occurs when Sun is directed at furthest point north or south of the equator; occurs in summer and winter, giving longest and shortest days of the year
Equinox
occurs when Sun is directly over equator; occurs in spring and fall, giving equal amounts of day/night
Tides
changes in ocean water levels that take place in regular pattern; controlled by pull of gravity between Moon and Earth; force of gravity of Moon pulls pulls ocean water away from Earth's surface
Spring Tide
occurs when new Moon or full Moon are lined up with Earth and Sun; combined gravity gives greatest difference between high/low tides
Neap Tide
occurs when first or third quarter Moon are at right angle with Earth and Sun; gives less difference between high/low tides
Crust
outermost layer of Earth; least dense layer; thinnest layer; where we live
Mantle
layer of Earth between crust and core; thickest layer, partially molten (liquid)
Lithosphere
made of crust and upper part of mantle; broken into tectonic plates
Asthenosphere
layer just inside of lithosphere; partially molten (liquid), allowing convection currents to move plates
Metamorphic Rocks
forms when other rocks are heated and squeezed together; requires heat and pressure
Igneous Rocks
formed when magma cools beneath Earth's surface or when lava cools at Earth's surface; forms in or around volcanoes; requires heat
Sedimentary Rocks
forms when sediment collects and hardens; layers of sediment pile up and squeeze together; requires pressure
Weathering
the breaking down of rock into smaller pieces, called sediment; can create/change geographic formations; agents: gravity, ice, wind, water
Mechanical Weathering
occurs when rocks are broken apart by physical processes; overall chemical makeup of the rock stays the same; ex. water freezing and thawing in cracks of rocks breaking them apart
Chemical Weathering
occurs when chemical reactions dissolve the minerals in rocks; changes the rock into different material from the original; ex. acid rain dissolving the minerals in rocks
Erosion
the movment of sediment; removes pieces of Earth from one pace and builds land in another; agents: gravity, ice, wind, water
Tectonic Plates
broken pieces of lithosphere; movement caused by convection currents in the asthenosphere
Continental Drift Theory
Alfred Wegener believed landmasses of Earth once fit together to form single landmass called "Pangaea"; landmasses "drifted" to where they are today; theory disregarded due to lack of evidence
Evidence of Continental Drift
-rock layers on coastlines of different continents match
-same species of plant/animal fossils found on different continents separated by oceans
-glacial ice in areas that are now located near the equator
-salt/coal deposits (which only form in warm climates) found in areas with cold climates
Plate Boundaries
place where tectonic plates meet; common site of geologic activity caused by moving plates
Convergent Boundary
occur where plates come together; volcanic or folded mountains are formed
Subduction Zone
where one plate moves under another; a deep ocean trench is formed
Divergent Boundary
occur where plates move away from each other; a rift valley or mid-ocean ridge is formed
Topographic Maps
show elevation of land with shape and spacing of contour lines; closer lines mean steeper slopes; flat places have widely spaced lines; series of increasingly smaller closed loops indicates hill or mountain
Convection Currents
caused by uneven heating of Earth's surface; Occur within Earth's atmosphere and oceans. Produce wind and ocean currents.
Wind
movement of air in the atmosphere caused by convection currents
Global Wind
heated air rises near the equator and moves toward Earth's poles, while cooler air at the poles falls and moves toward the equator; move in a particular direction across Earth over long distances; often steer weather in different directions
Local Wind
along shorelines; blows in toward the shore during the daytime; blows away from the shore at night.
Land Breezes
a coastal breeze blowing at night from land to sea; caused by the difference in the rate of cooling of their surfaces
Sea Breezes
wind blowing from a cool ocean surface onto adjoining warm land
Surface Ocean Currents
caused by global winds pushing along the surface of the ocean
Deep Ocean Currents
convection currents occurring deep in the ocean
HIgh Pressure (weather)
usually caused by air masses being cooled; often associated with good weather ("happy highs")
Low Pressure (weather)
usually happen along the boundary between warm and cold air masses; often associated with bad weather ("lousy lows")
Cold Front
when a cold, dry air mass takes the place of a warm, moist air mass; brings violent storms followed by fair, cooler weather; move quickly
Warm Front
when a warm, less dense air mass overtakes a cold, dense air mass; brings rain and showers followed by warmer, more humid weather; move slowly
Hurricane
intense low pressure areas that form over warm ocean waters in the summer and early fall; a powerful, spiraling storm.
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