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2. Standardized Test Prep
Resources
Chapter Presentation
Visual Concepts
Transparencies
Standardized Test Prep
Brain Food Video Quiz

3. Chapter 29 Table of Contents Section 1 Structure of the Sun
Section 2 Solar Activity

4. Chapter 29
Section 1 Structure of the Sun
Objectives
Explain how the sun converts matter into energy in its core.
Compare the radiative and convective zones of the sun.
Describe the three layers of the sun’s atmosphere.

5. Chapter 29 The Sun’s Energy Composition of the Sun
Section 1 Structure of the Sun
The Sun’s Energy
Composition of the Sun
Using a device called a spectrograph, scientists break up the sun’s light into a spectrum.
Dark lines form in the spectra of stars when gases in the stars’ outer layers absorb specific wavelengths of the light that passes through the layers.
By studying the spectrum of a star, scientists can determine the amounts of elements that are present in a star’s atmosphere.

6. The Sun’s Energy, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Energy, continued
Composition of the Sun
Because each element produces a unique pattern of spectral lines, astronomers can match the spectral lines of starlight to those of Earth’s elements, and identify the elements in the star’s atmosphere.
Both hydrogen and helium occur in the sun. About 75% of the sun’s mass is hydrogen, and hydrogen and helium together make up about 99% of the sun’s mass.
The sun’s spectrum reveals that the sun contains traces of almost all other chemical elements.

7. The Sun’s Energy, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Energy, continued
Nuclear Fusion
nuclear fusion the process by which nuclei of small atoms combine to form a new, more massive nucleus; the process releases energy
Nuclear fusion occurs inside the sun. Nuclei of hydrogen atoms are the primary fuel for the sun’s fusion.
Nuclear fusion produces most of the suns’ energy and consists of three steps.

8. The Sun’s Energy, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Energy, continued
Nuclear Fusion
In the first step, two hydrogen nuclei, or protons, collide and fuse. In this step, the positive charge of one of the protons is neutralized as that proton emits a particle called a positron.
As a result, the proton becomes a neutron and changes the original two protons into a proton-neutron pair.

9. The Sun’s Energy, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Energy, continued
Nuclear Fusion
In the second step, another proton combines with this proton-neutron pair to produce a nucleus made up of two protons and one neutron.
In the third step, two nuclei made up of two protons and one neutron collide and fuse.
As this fusion happens, two protons are released. The remaining two protons and two neutrons are fused together and form a helium nucleus. At each step, energy is released.

10. The Sun’s Energy, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Energy, continued
The diagram below shows nuclear fusion.

11. The Sun’s Energy, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Energy, continued
The Final Product
One of the final products of the fusion of hydrogen in the sun is always a helium nucleus.
The helium nucleus has about 0.7% less mass than the hydrogen nuclei that combined to form it do. The lost mass is converted into energy during the series of fusion reactions that forms helium.
The energy released during the three steps of nuclear fusion causes the sun to shine and gives the sun its high temperature.

12. Chapter 29
Section 1 Structure of the Sun
Nuclear Fusion

13. Mass Changing into Energy
Chapter 29
Section 1 Structure of the Sun
Mass Changing into Energy
The sun’s energy comes from fusion, and the mass that is lost during fusion becomes energy.
In 1905, Albert Einstein proposed that a small amount of matter yields a large amount of energy. This proposal was part of Einstein’s special theory of relativity.
This theory included the equation:
E = mc2

14. Mass Changing into Energy
Chapter 29
Section 1 Structure of the Sun
Mass Changing into Energy
In Einstein’s equation E = mc2, E represents energy produced; m represents the mass; and c represents the speed of light, which is about 300,000 km/s.
Einstein’s equation can be used to calculate the amount of energy produced from a given amount of matter.
By using Einstein’s equation, astronomers were able to explain the huge quantities of energy produced by the sun.

15. Chapter 29
Section 1 Structure of the Sun
Reading check
How did the equation E = mc2 help scientists understand the energy of the sun?

16. Reading check, continued
Chapter 29
Section 1 Structure of the Sun
Reading check, continued
How did the equation E = mc2 help scientists understand the energy of the sun?
Einstein’s equation helped scientists understand the source of the sun’s energy. The equation explained how the sun could produce huge amounts of energy without burning up.

17. Chapter 29 The Sun’s Interior The Core Section 1 Structure of the Sun
Careful studies of motions on the sun’s surface have supplied more detail about what is happening inside the sun. The parts of the sun include the core, the radiative zone, and the convective zone.
At the center of the sun is the core. The core makes up 25% of the sun’s total diameter of 1,390,000 km. The temperature of the core is about 15,000,000 kmºC.
The core is made up entirely of ionized gas, and is 10 times as dense as iron.

18. The Sun’s Interior, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Interior, continued
The Radiative Zone
radiative zone the zone of the sun’s interior that is between the core and the convective zone and in which energy moves by radiation
The radiative zone of the sun surrounds the core.
The temperature of the radiative zone ranges from about 2,000,000ºC to 7,000,000 ºC .
In the radiative zone, energy moves outward in the form of electromagnetic waves, or radiation.

19. The Sun’s Interior, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Interior, continued
The Convective Zone
Convective zone the region of the sun’s interior that is between the radiative zone and the photosphere and in which energy is carried upward by convection
The convective zone surrounds the radiative zone. The temperature of the convective zone is about 2,000,000ºC.
Energy produced in the core moves through this zone by convection.
Convection is the transfer of energy by moving matter.

20. The Sun’s Interior, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Interior, continued
The diagram below shows the layers of the sun.

21. Chapter 29 The Sun’s Atmosphere Section 1 Structure of the Sun
The sun’s atmosphere surrounds the convective zone of the sun’s core.
Because the sun is made of gases, the term atmosphere refers to the uppermost region of solar gases.
The sun’s atmosphere has three layers: the photosphere, the chromosphere, and the corona.

22. Chapter 29 The Sun’s Atmosphere The Photosphere
Section 1 Structure of the Sun
The Sun’s Atmosphere
The Photosphere
photosphere the visible surface of the sun
Photosphere means “sphere of light.” The photosphere of the sun is the innermost layer of the sun’s atmosphere.
The photosphere is made of gases that have risen from the convective zone. The temperature in the photosphere is about 6,000ºC.
Much of the energy given off from the photosphere is in the form of visible light.

23. The Sun’s Atmosphere, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Atmosphere, continued
Reading Check
What layers make up the sun’s atmosphere?

24. The Sun’s Atmosphere, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Atmosphere, continued
Reading Check
What layers make up the sun’s atmosphere?
The sun’s atmosphere consists of the photosphere, the chromosphere, and the corona.

25. The Sun’s Atmosphere, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Atmosphere, continued
The Chromosphere
chromosphere the thin layer of the sun that is just above the photosphere and that glows a reddish color during eclipses
The chromosphere lies just above the photosphere. The chromosphere’s temperature ranges from 4,000°C to 50,000 °C.
The gases of the chromosphere move away from the photosphere, forming narrow jets of hot gas that shoot outward and then fade away within a few minutes.

26. The Sun’s Atmosphere, continued
Chapter 29
Section 1 Structure of the Sun
The Sun’s Atmosphere, continued
The Sun’s Outer Parts
corona the outermost layer of the sun’s atmosphere
The corona is a huge region of gas that has a temperature above 1,000,000ºC.
As the corona expands, electrons and electrically charged particles called ions stream out into space.
These particles make up solar wind, which flows outward from the sun to the rest of the solar system.

27. Chapter 29
Section 1 Structure of the Sun
The Sun’s Atmosphere

28. Chapter 29
Section 1 Structure of the Sun
Structure of the Sun

29. Chapter 29
Section 2 Solar Activity
Objectives
Explain how sunspots are related to powerful magnetic fields on the sun.
Compare prominences, solar flares, and coronal mass ejections.
Describe how the solar wind can cause auroras on Earth.

30. Chapter 29
Section 2 Solar Activity
Sunspots
sunspot a dark area of the photosphere of the sun that is cooler than the surrounding areas and that has a strong magnetic field.
The movements of gases within the sun’s convective zone and the movements caused by the sun’s rotation produce magnetic fields.
These magnetic fields cause convection to slow in parts of the convective zone.

31. Chapter 29
Section 2 Solar Activity
Sunspots
Slower convection causes a decrease in the amount of gas that is transferring energy from the core of the sun to these regions of the photosphere.
Because less energy is being transferred, these regions of the photosphere are considerably cooler than surrounding regions, and form areas fo the sun that appear darker than their surrounding regions.
These, cooler, darker areas are called sunspots.

32. Chapter 29 The Sunspot Cycle
Section 2 Solar Activity
The Sunspot Cycle
Observations of sunspots have shown that the sun rotates.
The numbers and positions of sunspots vary in a cycle that lasts about 11 years.
Sunspots initially appear in groups about midway between the sun’s equator and poles. The number of sunspots increases over the next few until it reaches a peak of 100 of more sunspots.
After the peak, the number of sunspots begins to decrease until it reaches a minimum.

33. Chapter 29
Section 2 Solar Activity
Sunspots

34. Chapter 29 Solar Ejections
Section 2 Solar Activity
Solar Ejections
Other solar activities are affected by the sunspot cycle, such as the solar-activity cycle.
The solar-activity cycle is caused by the changing solar magnetic field.
This cycle is characterized by increases and decreases in various types of solar activity, including solar ejections.
Solar ejections are events in which the sun emits atomic particles.

35. Solar Ejections, continued
Chapter 29
Section 2 Solar Activity
Solar Ejections, continued
Prominences
prominence a loop of relatively cool, incandescent gas that extends above the photosphere.
Solar ejections include prominences, solar flares, and coronal mass ejections.
Prominences are huge arches of glowing gases that follow the curved lines of the magnetic force from a region of one magnetic force to a region of the opposite magnetic polarity.

36. Solar Ejections, continued
Chapter 29
Section 2 Solar Activity
Solar Ejections, continued
Solar Flares
solar flare an explosive release of energy that comes from the sun and that is associated with magnetic disturbances on the sun’s surface
Solar flares are the most violent of all solar disturbances.
Solar flares release the energy stored in the strong magnetic fields of sunspots. This release can lead to the formation of coronal loops.

37. Solar Ejections, continued
Chapter 29
Section 2 Solar Activity
Solar Ejections, continued
Coronal Mass Ejections
coronal mass ejection a part of coronal gas that is thrown into space from the sun
Some of the particles from a solar flare escape into space, increasing the strength of the solar wind.
Particles also escape as coronal mass ejections. The particles in the ejection can cause disturbances to Earth’s magnetic field.
These disturbances have been known to interfere with radio communications, satellites, and even cause blackouts.

38. Solar Ejections, continued
Chapter 29
Section 2 Solar Activity
Solar Ejections, continued
Reading Check
How do coronal mass ejections affect communications on Earth?

39. Solar Ejections, continued
Chapter 29
Section 2 Solar Activity
Solar Ejections, continued
Reading Check
How do coronal mass ejections affect communications on Earth?
Coronal mass ejections generate sudden disturbances in Earth’s magnetic field. The high-energy particles that circulate during these storms can damage satellites, cause power blackouts, and interfere with radio communications.

40. Chapter 29 Auroras Section 2 Solar Activity
aurora colored light produced by charged particles from the solar wind and from the magnetosphere that react with and excite the oxygen and nitrogen of Earth’s upper atmosphere; usually seen in the sky near Earth’s magnetic poles.
Auroras are the result of the interaction between the solar wind and Earth’s magnetosphere.
Auroras are usually seen close to Earth’s magnetic poles because electrically charged particles are guided toward earth’s magnetic poles by Earth’s magnetosphere.

41. Chapter 29 Maps in Action SXT Composite Image of the Sun

42. Chapter 29
The Sun
Brain Food Video Quiz

43. Chapter 29 Multiple Choice What is the source of the sun’s energy?
Standardized Test Prep
Multiple Choice
What is the source of the sun’s energy?
A. nuclear fission reaction that break down massive nuclei to form lighter atoms
B. nuclear fusion reactions that combine smaller nuclei to form more massive ones
C. reactions that strip away electrons to form lighter atoms
D. Reactions that strip away electrons to form more massive ones

44. Chapter 29 Multiple Choice What is the source of the sun’s energy?
Standardized Test Prep
Multiple Choice
What is the source of the sun’s energy?
A. nuclear fission reaction that break down massive nuclei to form lighter atoms
B. nuclear fusion reactions that combine smaller nuclei to form more massive ones
C. reactions that strip away electrons to form lighter atoms
D. Reactions that strip away electrons to form more massive ones

45. Chapter 29 Multiple Choice
Standardized Test Prep
Multiple Choice
2. What do electrically charged particles from the sun strike in Earth’s magnetosphere to produce sheets of light known as auroras?
F. gas molecules
G. dust particles
H. water vapor
I. ice crystals

46. Chapter 29 Multiple Choice
Standardized Test Prep
Multiple Choice
2. What do electrically charged particles from the sun strike in Earth’s magnetosphere to produce sheets of light known as auroras?
F. gas molecules
G. dust particles
H. water vapor
I. ice crystals

47. Chapter 29 Multiple Choice
Standardized Test Prep
Multiple Choice
3. Which layer of the sun has the densest material?
A. the corona
B. the convection zone
C. the radiative zone
D. the core

48. Chapter 29 Multiple Choice
Standardized Test Prep
Multiple Choice
3. Which layer of the sun has the densest material?
A. the corona
B. the convection zone
C. the radiative zone
D. the core

49. Chapter 29 Multiple Choice
Standardized Test Prep
Multiple Choice
4. Based on the amount of fuel the sun possessed at its formation, the life span of the sun is thought by scientists to be how long?
F. 1 billion years
G. 5 billion years
H. 10 billion years
I billion

50. Chapter 29 Multiple Choice
Standardized Test Prep
Multiple Choice
4. Based on the amount of fuel the sun possessed at its formation, the life span of the sun is thought by scientists to be how long?
F. 1 billion years
G. 5 billion years
H. 10 billion years
I. 50 billion

51. Chapter 29 Multiple Choice
Standardized Test Prep
Multiple Choice
5. The solar activity cycle occurs regularly every
A. 5 years
B. 11 years
C. 16 years
D. 22 years

52. Chapter 29 Multiple Choice
Standardized Test Prep
Multiple Choice
5. The solar activity cycle occurs regularly every
A. 5 years
B. 11 years
C. 16 years
D. 22 years

53. Chapter 29 Short Response
Standardized Test Prep
Short Response
6. In which part of the sun’s interior is energy carried to the sun’s surface by moving matter?

54. Chapter 29 Short Response
Standardized Test Prep
Short Response
6. In which part of the sun’s interior is energy carried to the sun’s surface by moving matter?
The convective zone

55. Short Response, continued
Chapter 29
Standardized Test Prep
Short Response, continued
7. What is the term for the innermost layer of the sun’s atmosphere?

56. Short Response, continued
Chapter 29
Standardized Test Prep
Short Response, continued
7. What is the term for the innermost layer of the sun’s atmosphere?
The photosphere

57. Chapter 29 Reading Skills Standardized Test Prep Studying the Sun
Read the passage below. Then, answer questions 8–10.
Studying the Sun
Sunlight that has been focused, especially through a magnifying glass, can produce a great amount of thermal energy - enough to start a fire. Imagine focusing the sun’s rays by using a magnifying glass that has a diameter of 1.6 m. The resulting heat could easily melt metal. If a conventional telescope were pointed directly at the sun, its parts could melt and become useless.
To avoid a meltdown, the McMath-Pierce telescope uses a special mirror that produces an image of the sun. This mirror directs the sun’s rays down a long, diagonal shaft to another mirror, which is located 50 m underground. This second mirror is adjustable, which allows it to focus the sunlight. The sunlight is then directed to a third mirror, which in turn directs the light to an observing room and instrument shaft. This system, while complex, not only protects the sensitive and expensive telescopic equipment but also protects the scientists that use it as well.

58. Reading Skills, continued
Chapter 29
Standardized Test Prep
Reading Skills, continued
8. According to information in the passage, which of the following statements about solar telescopes is true?
A. Solar telescopes allow scientists to safely observe the sun.
B. Solar telescopes do not need mirrors to focus the sun’s rays.
C. All solar telescopes are built 50 m underground.
D. All solar telescopes are built with a diameter of 1.6 m.

59. Reading Skills, continued
Chapter 29
Standardized Test Prep
Reading Skills, continued
8. According to information in the passage, which of the following statements about solar telescopes is true?
A. Solar telescopes allow scientists to safely observe the sun.
B. Solar telescopes do not need mirrors to focus the sun’s rays.
C. All solar telescopes are built 50 m underground.
D. All solar telescopes are built with a diameter of 1.6 m.

60. Reading Skills, continued
Chapter 29
Standardized Test Prep
Reading Skills, continued
9. Which of the following statements can be inferred from the information in the passage?
F. Focusing sunlight can help avoid a meltdown.
G. Unfocused sunlight produces little energy.
H. A magnifying glass can focus sunlight to produce a great amount of thermal energy.
I. Mirrors greatly increase the intensity and danger of studying sunlight.

61. Reading Skills, continued
Chapter 29
Standardized Test Prep
Reading Skills, continued
9. Which of the following statements can be inferred from the information in the passage?
F. Focusing sunlight can help avoid a meltdown.
G. Unfocused sunlight produces little energy.
H. A magnifying glass can focus sunlight to produce a great amount of thermal energy.
I. Mirrors greatly increase the intensity and danger of studying sunlight.

62. Reading Skills, continued
Chapter 29
Standardized Test Prep
Reading Skills, continued
10. Why do scientists have to use specialized equipment to study the sun?

63. Reading Skills, continued
Chapter 29
Standardized Test Prep
Reading Skills, continued
10. Why do scientists have to use specialized equipment to study the sun?
Conventional equipment would be at risk of melting under the intensity of the sun’s rays. Scientists’ eyesight could also be put at risk by looking directly at the sun.

64. Interpreting Graphics
Chapter 29
Standardized Test Prep
Interpreting Graphics
Use the figure below to answer questions The figure shows the structure of the sun.

65. Interpreting Graphics, continued
Chapter 29
Standardized Test Prep
Interpreting Graphics, continued
11. Fusion reactions provide power for the stars, such as the sun. In which part of the sun do these fusion reactions take place?
A. layer B
B. layer C
C. layer D
D. layer E

66. Interpreting Graphics, continued
Chapter 29
Standardized Test Prep
Interpreting Graphics, continued
11. Fusion reactions provide power for the stars, such as the sun. In which part of the sun do these fusion reactions take place?
A. layer B
B. layer C
C. layer D
D. layer E

67. Interpreting Graphics, continued
Chapter 92
Standardized Test Prep
Interpreting Graphics, continued
12. What is the term fro the dark, cool regions of the sun, which are represented by the letter E on the diagram?

68. Interpreting Graphics, continued
Chapter 29
Standardized Test Prep
Interpreting Graphics, continued
12. What is the term fro the dark, cool regions of the sun, which are represented by the letter E on the diagram?
sunspots

69. Interpreting Graphics
Chapter 29
Standardized Test Prep
Interpreting Graphics
Use the figure below to answer question 13. The figure
shows what happens when Earth’s magnetic field
interacts with the solar wind.

70. Interpreting Graphics, continued
Chapter 29
Standardized Test Prep
Interpreting Graphics, continued
13. How does the solar wind affect humans and other living things on Earth, despite the protection provided by the magnetosphere? Use examples to explain your answer.

71. Interpreting Graphics, continued
Chapter 29
Standardized Test Prep
Interpreting Graphics, continued
13. How does the solar wind affect humans and other living things on Earth, despite the protection provided by the magnetosphere? Use examples to explain your answer.
Your answer should explain that the magnetosphere extends far into space and protects the planet from many of the effects of the solar wind, a stream of ionized particles from the sun’s corona and include an example such as the fact that there are small gaps in the shield at the poles through which some particles can pass, or that radiation from solar flares can generate magnetic storms and may disrupt radio communications, or interfere with power grids.

72. Chapter 29
Nuclear Fusion

73. Chapter 29
The Sun’s Interior

74. SXT Composite Image of the Sun
Chapter 29
SXT Composite Image of the Sun