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Stars in A Box: Background Science

1. The document provides instructions for creating a Hertzprung-Russell diagram to model stars and their properties. Students will create circles of colored paper to represent stars of different temperatures and place them in the appropriate positions on the diagram. 2. The Hertzprung-Russell diagram plots stars' temperatures on the x-axis against their luminosities on the y-axis, showing their stage of life. Most stars exist on the main sequence as they burn hydrogen. 3. Students answer questions about how stars' colors, temperatures, luminosities and positions on the diagram relate to their properties like size and stage of life.

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Gergana Slavcheva
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138 views3 pages

Stars in A Box: Background Science

1. The document provides instructions for creating a Hertzprung-Russell diagram to model stars and their properties. Students will create circles of colored paper to represent stars of different temperatures and place them in the appropriate positions on the diagram. 2. The Hertzprung-Russell diagram plots stars' temperatures on the x-axis against their luminosities on the y-axis, showing their stage of life. Most stars exist on the main sequence as they burn hydrogen. 3. Students answer questions about how stars' colors, temperatures, luminosities and positions on the diagram relate to their properties like size and stage of life.

Uploaded by

Gergana Slavcheva
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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Stars in a box

Material list:

 2x 1-metre ruler/ strips of ribbon/ string or similar

 Coloured paper (white, blue, orange, red, yellow)

 Printed Axis Labels

 Scissors 

 Stellar Fact Sheet (per student)

Background science
A Hertzprung-Russell diagram shows the temperatures of stars plotted against their luminosities. The
position of a star on the diagram provides information about its information about the phase of life it
is currently in and its mass. The longest phase in any star's life is the so-called main sequence during
which they burn hydrogen into helium. The diagonal branch on the plot shows the main sequence.
Red dwarfs are cool and faint, they lie in the bottom-right corner. Blue supergiants are hot and
bright, they lie in the top-left corner.

When a star exhausts all its hydrogen, it leaves the main sequence and becomes a red giant or a
supergiant, depending on its mass. Stars with the mass of the Sun which have burnt all their fuel
evolve finally into a white dwarf.

Preparation

Before beginning the activity, clear a table or floor space and lay out your rulers at a 90° angle, these
will act as the Y-axis and X-axis for your H-R diagram. The Y-axis will represent Luminosity relative to
the Sun (L☉), this will be shown logarithmically from 0.0001 to 1000000. The X-axis will
show Temperature in Kelvin (K), the hottest temperature should be at least 35,000K and the lowest
around 2,000K.

Create a model of the Sun for reference. Using yellow paper, draw a circle with a radius of 2.5cm and
cut it out. Place this on the H-R diagram at 6,000 K and 1L ⊙.

Steps:

1. Background science
2. Stellar Fact Sheets
3. Collect a piece of coloured paper. You must choose the correct colour for the star based on
temperature (e.g. Betelgeuse should be red)
Spectral Class Temperature Colour

O 30,000 - 60,000 K Blue

B 10,000 - 30,000 K Blue-white

A 7,500 - 10,000 K White

F 6,000 - 7,500 K Yellow-white

G 5,000 - 6,000 K Yellow

K 3,500 - 5,000 K Orange

M < 3,500 K Red

4. Draw a circle of the correct size relative to the Sun model and the other stars on the Stellar
Fact sheet. Note that even the largest star will be no bigger than the size of an A4 sheet.
5. Choose other stars so that you end up with circles representing all stars on the sheet.
6. Place your stars on the H-R diagram one at a time.
7. Answer the questions:

a. What is the approximate temperature of the Sun? 


b.What colour would a star with the following surface temperature be:
18000K, 2000K,10000K
c. What factor affects the colour of a star?
d. What factor affects the luminosity of a star?

e.Most of the stars on the H-R Diagram are classified as which type of star?
f. What type of star has a high temperature but a low luminosity?
g. What type of star has a high temperature and a high luminosity?
h. What type of star has a low temperature but a high luminosity?
i. What type of star has a low temperature and a low luminosity?
j. Is the surface temperature of a white dwarf higher or lower than a red supergiant?
k. What property of a star uniquely determines where it will be on the Main Sequence?
l. If you increase the temperature of a star and leave it’s size the same, which way would it
move on the H-R diagram?
m. How do we know a star is larger than the Sun from it’s position on the H-R diagram?
n. What do we know about stars directly below the Sun on the H-R Diagram?

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