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Class
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Skills Worksheet
Directed Reading B
Section: Stars (pp. 436–443)
1. What is a star made of?
2. To learn about stars, astronomers study
.
COLOR OF STARS
______ 3. What color are the hottest stars?
a. blue
b. yellow
c. white
d. red
4. What can we conclude about stars that differ in color?
COMPOSITION OF STARS
______ 5. The band of colors produced when white light passes through a prism
is a(n)
a. color wheel.
b. emission line.
c. ultraviolet light.
d. spectrum.
______ 6. A hot, solid object gives off a(n)
a. continuous spectrum.
b. absorption spectrum.
c. emission line.
d. partial spectrum.
______ 7. What colors are shown in a continuous spectrum?
a. primary colors
b. cool colors
c. warm colors
d. all colors
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Stars, Galaxies, and the Universe
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Directed Reading B continued
______ 8. The colors that appear when a chemical element emits light are called
a. continuous lines.
b. absorption lines.
c. color lines.
d. emission lines.
______ 9. Each element in a hot gas can be identified by
a. a unique set of bright emission lines.
b. a unique set of bright absorption lines.
c. a set of emission lines shared with other elements.
d. a set of absorption lines shared with other elements.
10. Why is the spectrum of a star called an absorption spectrum?
11. How is an absorption spectrum produced?
12. What do the black lines of a star’s spectrum represent?
13. In what ways is the pattern of lines in a star’s absorption spectrum unique?
14. Why is it often difficult to identify a star’s elements from its absorption
spectrum?
15. What are the two main elements found in stars?
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Holt California Physical Science
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Stars, Galaxies, and the Universe
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Directed Reading B continued
16. What are the three most common trace elements found in stars?
CLASSIFYING STARS
______ 17. In the 1800s, astronomers classified stars according to
a. their elements.
b. their temperature.
c. their age.
d. their size.
______ 18. Stars are now classified by
a. their elements.
b. their temperature.
c. their age.
d. their size.
______ 19. Class O stars, the hottest stars, are
a. yellow.
b. orange.
c. red.
d. blue.
20. Early astronomers called the brightest stars in the sky
stars.
21. What type of numbers are used to represent the magnitudes of dim stars?
22. What type of numbers are used to represent the magnitudes of very bright
stars?
HOW BRIGHT IS THAT STAR?
23. The brightness of a star as seen from Earth is its
.
24. The brightness that a star would have at a distance of 32.6 light-years from
Earth is its
.
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Holt California Physical Science
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Stars, Galaxies, and the Universe
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Directed Reading B continued
25. Why is the sun the brightest object in the sky?
DISTANCE TO THE STARS
______ 26. What unit of measurement do astronomers use to measure the
distance from Earth to the stars?
a. a solar year
b. a parallax
c. a light-year
d. magnitude
27. The distance that light travels in one year; about 90.46 trillion kilometers, is
called a(n)
.
28. An apparent shift in the position of an object when seen from different
locations is called
.
MOTIONS OF STARS
29. Explain why you see different constellations in the sky at different times of
the year.
30. What causes the stars to appear to make one complete circle around Polaris
every 24 hours?
31. Why is the actual motion of the stars difficult to see?
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Holt California Physical Science
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Stars, Galaxies, and the Universe