Name ____________________________ Date ____________________ Class ____________ The Solar System
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Guided Reading and Study
The Sun This section describes the sun’s interior and its atmosphere. It also describes features on and above the sun’s surface.
Use Target Reading Skills As you read about the sun, complete the outline to show the relationships among the headings. The Sun I. The Sun’s Interior ________________________ ________________________ ________________________ II. ________________________ ________________________ B. The Chromosphere ________________________ ________________________ III. ________________________ ________________________ ________________________ C. Solar Flares
The Sun’s Interior 1.
The sun’s energy comes from a process called ________________________.
2.
What occurs in nuclear fusion? ________________________________________________________________________
_____________________________________________________________________ 3.
Where does nuclear fusion occur in the sun? ________________________________________________________________________
_____________________________________________________________________ 4.
Order the layers of the sun’s interior from inner layer to outer layer. ________________________________________________________________________
_____________________________________________________________________
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Name ____________________________ Date ____________________ Class ____________ The Solar System
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Guided Reading and Study
The Sun’s Atmosphere 5.
Order the layers of the sun’s atmosphere from inner layer to outer layer. _______________________________________________________________
6.
Which layer do you see when you look at a typical image of the sun? ________________________________________________________________________
7.
How can you identify the chromosphere during a total solar eclipse? ________________________________________________________________________
8.
Why can you see a corona during a total solar eclipse? ________________________________________________________________________ ________________________________________________________________________
9.
The corona sends out a stream of electrically charged particles called the ________________________.
10. Name three features on or above the sun’s surface. a. ________________________
b. ________________________
c. ________________________ Match the feature on the sun with its description. Feature ____ 11. sunspots ____ 12. prominences
Description a. Areas of gas on the sun’s surface that are cooler than the gases around them
____ 13. solar flares
b. Large eruptions of gas out into space c. Reddish loops of gas that link different parts of sunspot regions
14. When solar flares increase solar wind from the corona, what do they cause in Earth’s upper atmosphere? ________________________
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The Solar System
Features on the Sun
Name ____________________________ Date ____________________ Class ____________ The Solar System
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Section Summary
The Sun Key Concepts ■ What are the three layers of the sun’s interior? ■
What are the three layers of the sun’s atmosphere?
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What features form on or above the sun’s surface?
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The Solar System
The sun’s mass is 99.8 percent of all the mass in the solar system. Because the sun is so large, its gravity is strong enough to hold all of the planets and other distant objects in orbit. Unlike Earth, the sun does not have a solid surface. Like Earth, the sun has an interior and an atmosphere. The sun’s interior consists of the core, radiation zone, and convection zone. Each layer has different properties. The sun produces an enormous amount of energy in its core, or central region. The sun’s energy comes from nuclear fusion. In the process of nuclear fusion, hydrogen atoms in the sun join to form helium. The light and heat produced by the sun’s core first pass through the middle layer of the sun’s interior, the radiation zone. The radiation zone is a region of very tightly packed gas where energy is transferred mainly in the form of electromagnetic radiation. The convection zone is the outermost layer of the sun’s interior. Hot gases rise from the bottom of the convection zone and gradually cool as they approach the top. Cooler gases sink, forming loops of gas that move heat toward the sun’s surface. The sun’s atmosphere consists of the photosphere, the chromosphere, and the corona. The inner layer of the sun’s atmosphere is called the photosphere. Photo means “light,” so the photosphere is the sphere that gives off visible light. At the beginning and end of a solar eclipse, you can see a reddish glow around the photosphere. This glow comes from the middle layer of the sun’s atmosphere, the chromosphere. Chromo means “color,” so the chromosphere is the “color sphere.” During a total solar eclipse, a fainter layer called the corona is visible. The corona sends out a stream of electrically charged particles called solar wind. Features on or above the sun’s surface include sunspots, prominences, and solar flares. Sunspots are areas of gas on the sun that are cooler than the gas around them. Sunspots usually occur in groups. Reddish loops of gas called prominences link different parts of sunspot regions. Sometimes the loops in sunspot regions suddenly connect, releasing large amounts of energy. The energy heats gas on the sun to millions of degrees Celsius, causing the gas to explode into space. These explosions are known as solar flares. Solar flares can greatly increase the solar wind.
Name ____________________________ Date ____________________ Class ____________ The Solar System
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Review and Reinforce
The Sun Understanding Main Ideas Label the diagram of the sun below. 1.
4.
2.
5.
3.
6.
Building Vocabulary Match each term with its description by writing the letter of the correct description in the right column on the line next to the term in the left column. ____
7. solar flare
____
8. core
____
9. chromosphere
____ 10. sunspot
a. the layer of the sun’s atmosphere that gives off visible light b. the layer of the sun’s atmosphere that has a reddish glow c. the layer of the sun’s atmosphere that looks like a halo during an eclipse
____ 11. corona ____ 12. nuclear fusion ____ 13. photosphere
d. areas of gas on the sun’s surface that are cooler than the gases around them
____ 14. solar wind
e. reddish loops of gas that link parts of sunspot regions
____ 15. prominence
f. eruptions that occur when the loops in sunspot regions suddenly connect
____ 16. radiation zone ____ 17. convection zone
g. a stream of charged particles produced by the corona h. the center of the sun i. the outermost layer of the sun’s interior j. the joining of hydrogen atoms to form helium k. the layer of the sun’s interior where energy is transferred mainly by electromagnetic radiation
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Name ____________________________ Date ____________________ Class ____________ The Solar System
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Enrich
Sunspot Clues Although sunspots were once unexplained blemishes on the sun’s surface, their behavior has helped solve some of the sun’s mysteries. One of these mysteries dealt with the rotation of the sun. Did it rotate, as did other large objects in the solar system? And, if it did rotate, what was its period of rotation? Astronomers helped answer these questions by observing the behavior of sunspots. The diagrams below show how a series of sunspots behave over time. N W
Observations of Sunspots E
S
Equator
C
A C
Equator
B
B Start
After 3 days
C B After 26.9 days
Answer the questions below on a separate sheet of paper. 1. How have astronomers inferred that the sun rotates? 2. In what direction does the sun rotate? 3. Sunspots at the equator take 26.9 days to move once around the sun. What can you infer about how long sunspots A and B take to move around the sun, compared to sunspot C, which is on the equator? 4. Why do astronomers say that the sun rotates once every 27 to 31 days, rather than give an exact number?
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The Solar System
Equator
A
A
Name ____________________________ Date ____________________ Class ____________ The Solar System
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Skills Lab
Stormy Sunspots During which years were electrical disturbances on Earth most common? In this lab, you will consider the relationship between sunspot activity and magnetic storms on Earth.
Problem How are magnetic storms on Earth related to sunspot activity? Skills Focus graphing, interpreting data Materials graph paper
ruler
Procedure 1. Use the data in the table to plot a line graph of sunspot activity between 1972 and 2002. Use the next page or graph paper. 2. On the graph, label the x-axis “Year.” Use a scale with 2-year intervals, from 1972 to 2002. 3. Label the y-axis “Sunspot Number.” Use a scale of 0 through 160 in intervals of 10. 4. Graph a point for the Sunspot Number for each year. 5. Complete your graph by drawing lines to connect the points. Sunspots Year
Sunspot Number
Year
Sunspot Number
1972
68.9
1988
100.2
1974
34.5
1990
142.6
1976
12.6
1992
94.3
1978
92.5
1994
29.9
1980
154.6
1996
8.6
1982
115.9
1998
64.3
1984
45.9
2000
119.6
1986
13.4
2002
104.0
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Name ____________________________ Date ____________________ Class ____________ The Solar System
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Skills Lab
Line Graph
The Solar System
Analyze and Conclude Write your answers on a separate sheet of paper. 1. Graphing Based on your graph, which years had the highest average Sunspot Number? The lowest average Sunspot Number? 2. Interpreting Data How often does the cycle of maximum and minimum activity repeat? 3. Interpreting Data When was the most recent maximum sunspot activity? The most recent minimum sunspot activity? 4. Inferring Compare your sunspot graph with the magnetic storms graph in your textbook. What relationship can you infer between periods of high sunspot activity and magnetic storms? Explain. 5. Communicating Suppose you are an engineer working for an electric power company. Write a brief summary of your analysis of sunspot data. Explain the relationship between sunspot number and electrical disturbances on Earth.
More to Explore Using the pattern of sunspot activity you found, predict the number of peaks you would expect in the next 30 years. Around which years would you expect the peaks to occur?
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