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48 terms

Science Flashcards

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astronomy
the study of the moon, stars, and other objects in space
axis
an imaginary line that passes through Earth's center and the north and south poles, about which Earth rotates
revolution
the movement of an object around another object
orbit
the path of an object as it revolves around another object in space
latitude
a measurement of distance from the equator, expressed in degrees north or south
solstice
The two days of the year on which the noon sun is directly overhead at either 23.5 degrees South or 23.5 degrees North
equinox
the two days of the year on which neither hemisphere is tilted toward or away from the sun
vernal equinox
the day of the year that marks the beginning of spring in the northern hemisphere
autumnal equinox
The day of the year that marks the beginning of fall in the Northern hemisphere
phase
one of the different shapes of the moon as seen from Earth
solar eclipse
the blocking of sunlight to earth that occurs when the moon is directly between the sun and earth
umbra
the darkest part of a shadow
penumbra
the part of a shadow surrounding the darkest part
lunar eclipse
the blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon
tide
The rise and fall of the level of water in the ocean
gravity
attractive force between two objects that depends on the masses of the objects and the distance between them
spring tide
a tide with the greatest difference between low and high tides
neap tide
a tide with the least difference between low and high tides
nuclear fusion
the process by which hydrogen atoms join together to form helium, releasing energy
core
The central part of the sun, where nuclear fusion takes place
photosphere
the inner layer of the suns atmosphere
chromosphere
The middle layer of the sun's atmosphere
corona
outer layer of the sun's atmosphere
solar wind
a stream of electrically charged particles produced by the sun's corona
sunspots
areas of gas on the sun's surface that are cooler than the gases around them
prominences
A loop of gas that protrudes from the sun's surface, linking parts of sunspot regions
solar flares
an explosion of hydrogen gas from the sun's surface that occurs when the loops in sunspot regions suddenly connects
continental drift
the hypothesis that the continents slowly move across Earth's surface
fossil
a trace of an ancient organism that has been preserved in rock
mid-ocean ridge
an undersea mountain chain where new ocean floor is produced; a divergent plate boundary
sonar
a device that determines the distance of an object under water by recording echoes of sound waves
deep-ocean trench
a deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle
subduction
the process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary
sea-floor spreading
the process by which molten material adds new oceanic crust to the ocean floor
focus
The point beneath Earth's surface where rock breaks under stress and causes an earthquake
epicenter
the point on Earth's surface directly above an earthquake's focus
seismograph
a device that records ground movements caused by seismic waves as they move through Earth
magnitude
The measurement of an Earthquake's strength based on seismic waves and movement along faults
Mercalli scale
A scale that rates earthquakes according to their intensity and how much damage they cause
Richter Scale
a scale that rates seismic waves as measured by a particular type of mechanical seismograph
moment magnitude scale
a scale that rates earthquakes by estimating the total energy released by an earthquake
seismic waves
vibrations that travel through Earth carrying the energy released during an earthquake
P waves
A type of seismic wave that compresses and expands the ground
S waves
A type of seismic wave that moves the ground up and down or side to side
surface waves
a type of seismic wave that forms when P waves and S waves reach Earth's surface
rotation
the spinning motion of a planet on its axis
eclipse
the partial or total blocking of one object in space by another
Pangaea
the name of the single landmass that broke apart 200 million years ago and gave rise to today's continents