Download Chapter 2 Test Review Vocabulary • axis – an imaginary line

Chapter 2 Test Review
Vocabulary
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axis – an imaginary line through the center of an object
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constellation – a group of stars that forms a pattern shaped like an animal, object, or person
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crescent moon – phase of the moon when only a thin shape can be seen
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equator – the imaginary line that circles Earth halfway between the North and South Poles
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full moon – phase of the moon when all the moon’s bring side is visible
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new moon – phase of the moon when none of the moon’s bright side is visible
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phases of the moon – the different ways the moon looks throughout the month
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quarter moon – the moon has revolved a quarter of the orbit around Earth and half of the moon’s sunlit side is
visible
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revolve – to move around another object
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rotate – to turn, or spin, on an axis
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season – one of the four parts of the year; spring, summer, fall, and winter
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star – a ball of hot gases that gives off light and other forms of energy
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waning moon – after a full moon, a decreasing amount of the sunlit side of the moon can be seen
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waxing moon – after a new moon, an increasing amount of the sunlit side of the moon can be seen
Day and Night
 What is an axis?
 An axis is an imaginary line through the center of an object.
 When one side of Earth is facing the sun, what part of day is it on the other side?
 On the other side of Earth, it is nighttime.
 How does the Earth’s rotation result in (cause) the day-night cycle?
 As it rotates every 24 hours, only one side is covered in sunlight, resulting in (causing) day and night.
 What effect does the sun have on the side of Earth where it is daytime?
 It gives light and hear to the side where it is daytime.
 What causes the sun to appear to move across the sky?
 Earth’s rotation causes the sun to move across the sky.
 How can scientists determine that the Earth is moving but the sun is not?
 They can observe Earth’s rotation from space. Observation through telescopes can confirm that the sun does not
move.
 What is the apparent path of the Sun? Why?
 The sun appears to rise in the east, move west and get higher in the sky, and then to move west and to set there. It
seems to move because Earth is rotating but the sun does not really move.
 How do shadows change throughout the day?
 When the sun is low in the sky, shadows are long, and when the sun is high in the sky, shadows are short.
Chapter 2 Test Review
 What causes shadows to change in length during the day?
 The changing angle of sunlight causes shadows to change length throughout the day.
 What can you measure to tell whether it is morning or noon where you live? Explain.
 You can measure the length of your shadow because my shadow is longer in the morning than at noon.
Seasons
 How many times each year does Earth revolve around the Sun?
 once
 Describe the location of the equator.
 The equator is an imaginary line located midway between the North Pole and the South Pole.
 Tell why we have seasons.
 The tilt of Earth is what causes the seasons. When Earth’s northern hemisphere tilts toward the sun it receives
direct sunlight, so it is summer there.
 In December, the southern hemisphere is tilted toward the sun. What season is it there in March?
 fall
 `Why is the sun lower in the sky in winter?
 It appears lower because Earth’s northern hemisphere points away from the sun in winter.
 Describe how the apparent position of the sun in the sky changes over a year, beginning in June.
 It would be at its highest point in June, get lower and lower during the fall until December, and then go higher
during the spring until reaching its peak again in June.
 If the sun is low in the sky during December in the northern hemisphere, where would it be in December in the
southern hemisphere?
 At its high point because it would be summer in the southern hemisphere.
 How would the strength of the sun’s rays differ in June and December? Why?
 The rays would be weaker in December because they are striking the northern hemisphere at a lower angle than
they are in June.
 In June, is the North Pole tilted toward or away from the Sun?
 toward
 Why is it warmer in the summer than in the winter?
 The days are longer and the sun rises higher in the summer.
 How is June different in North American than it is in Australia?
 In North America, June is summer; in Australia, it is winter.
 Would seasons occur (happen) even if Earth were not tilted on its axis?
 No, seasons occur (happen) as Earth’s position changes, which happens because of the tilt.
 How would you place Earth and its axis in an Earth-Sun model for December?
 You would tilt the axis so that the North Pole is pointing away from the sun.
Chapter 2 Test Review
Moon Phases
 What are two different ways that the moon moves?
 The moon rotates and revolves.
 How is the moon different from the sun?
 The sun makes it own light and has no phases. The moon has phases and reflects the sun’s light.
 When does the moon look like a thin sliver?
 When you can only see a small part of its bright side, it is called a crescent moon.
 If the sun, moon, and Earth never moved, would the moon have phases?
 No it would always look the same.
 What phase of the moon occurs when all of the moon’s sunlit side faces Earth?
 full moon
 How can we see the moon if it gives off no light?
 We see it by light it reflects from the sun.
 What is the opposite of a new moon?
 full moon
 Why does the moon’s shape look different on different nights?
 As the moon revolves around Earth, different amounts of its bright side can be seen.
Stars
 Why does the sun look larger than the other stars you can see?
 The sun looks larger than other stars you can see because it is so much closer to Earth than any other star.
 Are all stars the same size?
 No, some are only the size of Earth while others are more than 500 million km wide.
 If most stars are very large, why do they look so small in the night sky?
 The stars are very far away.
 Is the sun a very large star?
 No, the sun is a medium-size star, although it is much bigger than Earth.
 Do the stars go away during the day?
 No, the stars are not visible during the day because the sun is so bright.
 Why do stars appear to move during the night?
 The stars appear to move because the Earth rotates.
 Name a constellation that can be seen all year from North America.
 the Small Bear
 If you see a constellation in the sky in November, would you expect to see the same constellation in May? Explain.
 It depends on which constellation you see. Some constellations that can be seen in November can also be seen in
May. Others can only be seen during one season.
Chapter 2 Test Review
 You see different constellations in the winter night sky. Have the stars moved? Why or why not?
 No, stars do not move; Earth has revolved around the sun.
 If Earth did not rotate would the position of a constellation change during the night? Explain.
 No because the stars do not really move; they seem to move because of Earth’s rotation.
 The constellation Lyra is called a “summer constellation” in North America. What do you think this means?
 A summer constellation is most easily seen during the summer months in North America.
 How does the movement of the stars in the sky compare to that of the planets?
 The stars appear to move in a fixed position. That is why constellations always form the same patterns. Planets
have different positions most nights because they are orbiting around the sun.
Diagrams
Last Quarter
Moon
Waning
Gibbous
Waning
Crescent
Sun
New Moon
Full Moon
Waxing
Crescent
Waxing
Gibbous
First Quarter
Spring
Seasons
Winter
Summer
Fall