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Activity – Constructing a Hertzsprung-Russell Diagram
Name: _________________________ Hour: ______
Problem:
What is the effect of a star’s temperature to its color?
Hypothesis: I think that a star’s temperature (does have, does not have) an effect on its color.
Item
colored pencils
worksheet
Materials
Amount
1set per group
1 per person
Use
to color with
to record on
Procedure:
1. Plot the data in the table on the graph.
2. Stars with surface temperatures up to 3,500 °C are red. Shade a vertical band from 2,000 °C to
3,500 °C a light red.
3. Shade other color bands as follows: Stars up to 5,000 °C are orange-red, up to 6,000 °C yellowwhite, up to 7,500 °C blue-white, and up to 40,000 °C blue.
4. Label the main sequence, the red supergiants, and the white dwarfs.
Conclusions:
1. Based on our results, we conclude that
________________________________________________________
_______________________________________________________.
2. What is the general relationship between temperature and star brightness?
_______________________________________________________.
3. What is the general relationship between star color and temperature?
_______________________________________________________.
4. How does the sun compare to other stars on the main sequence?
_______________________________________________________.
5. What star class does our sun belong to? ________________________________.
6. A star is classified as being in class B. What is its color? Temperature?
_______________________________________________________.
7. We know dwarfs are small—smaller than our sun? How can they be so bright?
_____________________________________________________________________________
_______________________________________________________.
Star-Brightness Data Table
Star Name
Sun
Alpha Centauri A
Alpha Centauri B
Barnard’s Star
Lalande 21185
Sirius A
Sirius B
Ross 248
61 Cygni A
61 Cygni B
Procyon A
Procyon B
Epsilon Indi
Canopus
Arcturus
Vega
Capella
Rigel
Betelgeuse
Achernar
Beta Centauri
Altair
Aldebaran
Spica
Antares
Deneb
Beta Crucis
Approximate
Temperature, °C
5,300
5,500
3,900
2,500
2,900
10,100
10,400
2,400
3,900
3,600
6,200
7,100
3,900
7,100
4,200
10,400
5,600
11,500
2,900
14,000
21,000
7,700
3,900
21,000
3,100
9,900
22,000
Brightness (Sun = 1)
1
1.3
0.36
0.0004
0.005
23
0.008
0.0001
0.08
0.04
7.6
0.0005
0.13
1,500
90
60
150
40,000
17,000
200
3,300
10
90
1,900
4,400
40,000
6,000
Activity – Constructing a Hertzsprung-Russell Diagram
Assessment Questions
1.
Which of the following is the “best” conclusion of this laboratory activity
a. A star’s temperature has no effect on its color.
b. A star’s color determines its temperature.
c. A star’s temperature determines its brightness.
d. The hottest stars emit shorter wavelengths of light and appear bluer, while cooler stars
appear more red.
2.
A star’s temperature is ______ related to its brightness.
a. directly
b. indirectly
c. not
The sun belongs to the spectral class
a. O.
b. A.
c. F.
3.
4.
The sun is
a. light red.
b. orange-red.
c. yellow-white.
d. blue-white.
e. blue.
5.
True or False: Supergiants are cooler than white dwarfs.
6.
True or False: A star’s color can be used to determine its temperature.
7.
True or False: A star’s color can be used to determine its size.
d. G.