Sun, Earth, Moon – Unit 3 Study Guide KEY
In this unit you will explore current scientific views of the universe and how those views evolved.
#1 Students will understand the effects of the relative positions of the earth, moon and sun.
Demonstrate the phases of the moon by showing the alignment of the earth, moon, and sun.
Explain the alignment of the earth, moon, and sun during solar and lunar eclipses.
Relate the tilt of the earth to the distribution of sunlight throughout the year and its effect
on climate.
#2 Students will explore current scientific views of the universe and how those views evolved.
Explain the motion of objects in the day/night sky in terms of relative position.
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As some point during this unit you will be asked to answer the following questions:
Why does the moon appear to change shapes?
How do lunar and solar eclipses differ?
How are lunar and solar eclipses alike?
Why does the Earth have different seasons?
How does the gravitational pull of the moon affect me when I am at the beach?
1. Isaac Newton developed a theory of gravity that helped to explain why the planets orbit the Sun and moons orbit planets.
2. What is an AU? An AU is an astronomical unit. It is the distance between the Earth and the Sun.
3. How many miles are in an AU? 93,000,000. We use AU to measure distance in our solar system.
4. Light travels at 186,000 miles per secondand it takes 8.3 minutes for light to travel from the Sun to Earth.
5. We measure distances outside our solar system in light years.
The Earth
6. The largest rocky planet in our solar system is Earth.
7. One theory about how the Earth formed states that while solar gas and dust (a nebula) were swirling around and slowly condensing to form the Sun, a small part of the nebula escaped the Sun’s gravity and became trapped in an orbit around the Sun.
8. Rotation is spinning on an axis.
9. Revolution is orbiting around another body.
10. Each time a planet orbits the sun another planetary year has passed.
11. The Earth’s planetary year is 365 days.
12. What is the exact amount of time it takes for the Earth to make one complete orbit around the Sun? 365.25 days OR 365 days and 6 hours.
13. Why do we have a leap year every four years? The Earth actually takes 365.25 days to orbit the Sun. To correct this .25 of a day mathematical problem with the calendar, we add 1 day every 4 years to account for that ¼ of a day.
Tides
14. The gravitational pull of the Moon, and to a lesser degree the Sun, interacts with the rotation of the Earth and the shape of ocean basins to produce the tides.
15. The gravitational pull from the moon, and the spinning of the earth, causes ocean water to bulge, producing the tides.
16. A synodic period is also known as the time it takes for the moon to change from one high tide to another high tide.
Seasons
17. Seasons are caused by the change in the angle of the Sun's rays on Earth due to the tilt of the Earth.
18. During June, The Northern Hemisphere is tilted toward the sun and the Southern Hemisphere is tilted away from the sun.
19. In June the Northern Hemisphere has summer and the Southern Hemisphere has winter.
20. During December, The Northern Hemisphere is tilted away from the sun and the Southern Hemisphere is tilted toward from the sun.
21. In December the Northern Hemisphere has winter and the Southern Hemisphere has summer.
22. The Earth is closest to the sun during which month? January
23. The poles have the most extreme difference in temperaturesthan any other place on Earth during their summer and their winter.
24. The sun’s rays are consistent year round at the equator.
25. The countries at the equator do not have seasons.
26. Because the Earth is tilted on its axis, sunlight falls more intensely on different parts of the Earth during the year. The difference in heating of the Earth’s surface produces the planet’s seasons and weather patterns.
27. The Summer solstice is on June 21. This day has the longest about of sunlight as any day during the year.
28. The Winter solstice is on December 21. This day has the least about of sunlight as any day during the year.
29. Equinox literally means "equal night"
30. The vernal (spring) equinox occurs March 21.
31. The autumnal (fall) equinox occurs September 21.
The sun
32. Approximately 99% of the solar system’s mass is located in the Sun.
33. The six parts of the sun are core, radiative zone, convective zone, photosphere, chromosphere, and corona.
34. Draw the layers of the sun.
35. The hottest layer of the sun is the core and the coolest layer is the photosphere.
36. The core is the location in the Sun where energy is produced.
37. The energy from the Sun is produced by nuclear fusion.
38. The coolest spots on the surface of the sun are sunspots.
39. Explosions on the surface of the sun that occasionally interferes with radio communications on Earth are called solar flares.
The Moon
40. One theory of how the moon formed is an extremely large celestial body collided with the Earth and the collision caused a large portion of the Earth’s mantle to break away and orbit the Earth.
41. The Moon’s revolution around the earth is the same as its rotation on its axis.
42. On Earth, we always see the same side of the Moon.
43. The moon is approximately 25 % orone-fourth the size of Earth.
44. The Moon is about 400 times smaller than the Sun, but it also happens to be about 400 times closer. The result is that from Earth, the moon and the sunappear to be the same size.
45. The Moon's light comes from the Sun, and the sunlight is reflected off the Moon's surface.
46. The Moon rises and sets almost 1 hour later each night.
47. The moon can be seen during the day. The time and length of daythe moon can be seen varies with the phase of the moon.
48. The same side of the Moon always faces the Earth because the Moon turns on its axis at the same rate as it revolves around the Earth.
49. The Sun's rays do strike the back side of the Moon. However, from our position on Earth, we never see the light striking the back side of the Moon.
Phases of the Moon
50. The moon orbits the Earth once in about 28 days.This changes whichhalfof the moon is lighted by the sun and how much of that part can be seen from the earth.
51. Waxing means to increase in size or grow larger.
52. Waning means to decrease in size or grow smaller.
53. Gibbous is when more than 50% of the moon is visible
54. Crescent is when less than 50% of the moon is visible.
55. The phase of the Moon that we see depends on the orientation of the Earth and Moon, relative to the Sun.
56. The Moon's phases are caused by the part of the lighted half we can see on earth.
57. The Moon changes in position in the sky each day.
58. The Moon changes in appearance,these changes are called phases.
59. The length of time from New Moon to New Moon is called the LUNAR MONTH or SYNODIC PERIOD of the Moon. It is 29.53 days.
60. The Moon rises in the east and sets in the west daily, but its position in the sky moves EASTWARD by about 13 degrees per day.
Eclipses
61. A lunar eclipse occurs when the moon passes through Earth’s shadow.
62. A lunar eclipse occurs when the Earth blocks the Sun’s light from hitting the moon.
63. During a lunar eclipse the moon passes through the shadow of the Earth.
64. A solar eclipse occurs when the moon passes between through Earth and the sun.
65. A solar eclipse occurs when the moon blocks the Sun’s light from hitting the Earth.
66. During a solar eclipse the Earth passes through the shadow of the Moon.
67. When its orbit around Earth takes the Moon directly between Earth and the Sun, the Moon blocks our view of the Sun in what we call a solar eclipse.
68. A Solar eclipse occurs only during which phase of the moon?New Moon
69. A Lunar eclipse occurs only during which phase of the moon? Full Moon
70. Why doesn’t a lunar eclipse occur every month during the full moon? The moon’s orbit around the Earth is at a slight tilt compared to the Earth’s orbit around the sun. The Earth is not directly between the Sun and the moon during every Full Moon phase.
71. Why doesn’t a solar eclipse occur every month during the new moon? The moon’s orbit around the Earth is at a slight tilt compared to the Earth’s orbit around the sun. The Moon is not directly between the Sun and the Earth during every New Moon phase.
VOCABULARY:
alignment - arrangement in a straight line
luminous - radiatingorreflectinglight
nuclear fusion - the source of all the energy radiated by the Sun; it converts hydrogen into helium
solar flares - a sudden temporary outburst of energy from a small area of the sun's surfacethat can affect the earth
sunspots - the dark spots that appear the sun's surface
Equinox - occurs twice a year (about March 21 and September 23) when the amount of sunlight is equal to the amount of darkness
Solstice - one of the two times during the year when the sun is farthest north or south of the equator
waxing - to increase in size or grow larger
waning - to decrease in size or grow smaller
gibbous- more than 50% of the side of the moon we see is lit by the sun
crescent- less than 50% of the side of the moon we see is lit by the sun
lunar eclipse - when the Earth blocks the Sun’s light from hitting the moons
solar eclipse - when the moon blocks the Sun’s light from hitting the Earth