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30 Cards in this Set
- Front
- Back
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day and night are caused by
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earths rotationon its axis
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earths rotation takes about
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24 hours
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one complete revolution of earth around the sun takes about
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one year
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earth has seasons because
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earths axis is tiltedas it moves around the sun
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when the north end of earths axis is tilted toward the sun, north america will experience
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more direct rays and longer days
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an equinox occurs when
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niether end of earth axis is tilted toward nor away from the sun
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the phase of the moon you see depends on
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how much of the sunlit side of the moon faces earth
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a lunar eclipse occurs when
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full moon phase
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a solar eclipse occurs when
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new moon phase
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tides are caused mainly by
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differences in how much the moon pulls on different parts of the earth
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the two factors that combine to keep the planet in orbit are
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gravity and inertia
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the tendency of a moving object to continue moving in a straigh line or a stationary object to remain in place is called
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inertia
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the inner planets have in common that they are
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small rocky surfaces
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the outer planet have in common that they are
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much larger than earth and do not have solid surfaces
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the shape of most comets orbits are
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long, narrow, ellipses
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when a meteoroid enters earths atmosphere, it produces a streak of light called a
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meteor
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the order of the planets form the sun outward are
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m,v,e,m,j,s,u,n
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the electromagnetic spectrum is
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all different types of electromagnetic waves
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the brightest star in our sky is
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sirius
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a lightyear is
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the distance light travels in a year
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parallax is a method used to determine a stars
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distance from earth
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stars are classifie according to their
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size, brightness and temperature
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the hottest stars are
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blue
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the coldest stars are
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red
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the hertzsprung russell diagram shows that main sequence stars
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increase in brightness as they increase in temperature
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the force that tends to pull together the matter in stars is
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gravity
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the lifetime of a star depends on its
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mass
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one indication that a planet may exist near another star is that
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there is a very slight drop in brightness whenever a planet passes in front of that star
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the milky way galaxy is a
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spiral galaxy
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one piece of edvidence that supports the big bang theory is the observation that most galaxies are moving
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away from one another
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