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The Sun
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Printed: February 2, 2014
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C ONCEPT
Concept 1. The Sun
1
The Sun
Lesson 24.3: True or False
Name___________________ Class______________ Date________
Write true if the statement is true or false if the statement is false.
_____ 1. The sun is divided into definite internal layers.
_____ 2. The hottest part of the sun has a temperature of about 27 million °C.
_____ 3. During nuclear fusion inside the sun, helium combines to form hydrogen.
_____ 4. A photon may travel through the radiative zone in just a few seconds.
_____ 5. Material that rises through the convective zone cools at the sun’s surface.
_____ 6. The photosphere has a grainy appearance because it has several different colors.
_____ 7. The sun’s corona has a much cooler temperature than its photosphere.
_____ 8. The sun’s atmosphere consists of three layers.
_____ 9. A sunspot occurs where a loop of the sun’s magnetic field breaks through the solar surface.
_____ 10. Sunspots usually occur in cycles that repeat every 21 years.
Lesson 24.3: Critical Reading
Name___________________ Class______________ Date________
Read this passage based on the text and answer the questions that follow.
Surface Features of the Sun
The most noticeable surface features of the sun are dark spots known as sunspots. Sunspots are located where loops
of the sun’s magnetic field break through the surface. This disrupts the smooth transfer of heat from lower layers
of the sun, making sunspots cooler and darker than the rest of the surface. Sunspots are also marked by intense
magnetic activity. Sunspots usually occur in pairs. When a loop of the sun’s magnetic field breaks through the
surface, a sunspot is created where the loop comes out of the surface. Another sunspot is created where the loop
goes back into the surface.
There are other types of interruptions of the sun’s magnetic field that are apparent on the surface. If a loop of the
sun’s magnetic field snaps and breaks, it creates a solar flare, which is a violent explosion that releases huge amounts
of energy. A solar flare releases streams of highly energetic particles that make up solar wind. Solar wind sends out
large amounts of radiation that can harm the human body, so it can be dangerous to astronauts in spacecraft. On
Earth, solar flares have knocked out entire power grids and disturbed radio, satellite, and cell phone communications.
Another highly visible feature on the sun’s surface is a solar prominence. A solar prominence is a glowing arch that
forms where plasma flows along a loop of the sun’s magnetic field from sunspot to sunspot. A solar prominence may
reach thousands of kilometers into the sun’s atmosphere. Prominences can last for a day to several months. They are
clearly visible during a total solar eclipse.
Questions
1
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1.
2.
3.
4.
Explain how sunspots form. Describe how they look and why they look this way.
Why do sunspots usually occur in pairs?
What is a solar flare. How do solar flares cause solar wind?
Describe a solar prominence. Explain how a solar prominence is related to sunspots.
Lesson 24.3: Multiple Choice
Name___________________ Class______________ Date________
Circle the letter of the correct choice.
1. About what percent of the total mass of the solar system consists of the sun?
a.
b.
c.
d.
1 percent
15 percent
75 percent
99 percent
2. Convective movement in the sun helps to create
a.
b.
c.
d.
solar flares.
sunspots.
photons.
two of the above
3. Which of the following layers of the sun has the highest temperature?
a.
b.
c.
d.
photosphere
chromosphere
radiative zone
corona
4. Solar flares can
a.
b.
c.
d.
knock out power grids.
be dangerous to astronauts.
disturb radio communications.
all of the above
5. Which statement about solar prominences is true?
a.
b.
c.
d.
They can reach thousands of kilometers into the sun’s atmosphere.
They are never visible, even during a total solar eclipse.
They last at most for a few minutes.
all of the above
6. NASA’s Solar Dynamics Observatory is
a.
b.
c.
d.
landing rovers on the sun’s surface.
providing high clarity images of the sun.
examining the sun’s innermost core.
two of the above
7. The matter of the sun
a.
b.
c.
d.
2
is made of superheated gas.
has a negative electrical charge.
forms a defined outer boundary.
has a maximum temperature of 1 million °C.
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Concept 1. The Sun
Lesson 24.3: Matching
Name___________________ Class______________ Date________
Match each definition with the correct term.
Definitions
_____ 1. outermost plasma layer of the sun that forms a halo around the sun
_____ 2. layer of the sun just outside the core through which energy from the core travels very slowly
_____ 3. glowing arch formed when plasma flows along a loop from sunspot to sunspot
_____ 4. layer of the sun just outside the radiative zone through which hot material rises
_____ 5. thin layer of the sun that glows red when heated by energy from the photosphere
_____ 6. violent explosion that occurs when a loop of the sun’s magnetic field snaps and breaks
_____ 7. relatively cool visible surface of the sun that emits sunlight
Terms
a. chromosphere
b. corona
c. photosphere
d. solar flare
e. solar prominence
f. convection zone
g. radiative zone
Lesson 24.3: Fill in the Blank
Name___________________ Class______________ Date________
Fill in the blank with the appropriate term.
1.
2.
3.
4.
5.
6.
7.
The sun’s energy comes from the type of reaction called nuclear __________.
Light energy travels as particles called__________.
Most atoms in the sun exist in the state of matter referred to as __________.
The sun is composed almost entirely of the elements hydrogen and __________.
Relatively cool, dark areas on the surface of the sun are known as __________.
A stream of highly magnetic particles from a solar flare makes up solar __________.
The innermost layer of the sun is called the __________ of the sun.
Lesson 24.3: Critical Writing
Name___________________ Class______________ Date________
Thoroughly answer the question below. Use appropriate academic vocabulary and clear and complete sentences.
3
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Explain why the sun has so much energy and how this energy travels from the sun’s core to its surface.
4