Name: __________________________
Hertzsprung-Russell Activity
The Hertzsprung-Russell (H-R) diagram is a graph relating the
surface temperatures and absolute brightness of stars.
Astronomers use H-R diagrams to classify stars and to understand
how stars change over time.
In this activity, students will create a H-R diagram, determine
where to place stars on their H-R diagram, and answer questions
that relate to their diagram.
Directions: Students will read and follow the instructions below
to create their H-R diagram. Students can also use page 132 in the
textbook to help.
1. Students will get a piece of oak tag paper or large white paper and
make model of the H-R diagram seen on the next page.
2. Students will put the title “Hertzsprung-Russell Diagram” at the top
of the paper.
3. Students will label the x-axis “Surface Temperature” and put the units
degrees Celsius.
4. Students will label the y-axis “Absolute Brightness”.
5. Students will put the corresponding number values on the x and yaxis. The values for the x-axis “Surface Temperature” are 3,000 to
50,000 degrees Celsius increasing from right to left. The values for
the y-axis “Absolute brightness” are six to zero with zero at the top
and six at the bottom.
6. Students will determine the color of each star in the star packet by
using their Characteristics of Stars notes. Students should use the
temperature of the star to determine its color. Students will color each
star the appropriate color using colored pencils.
7. Students will cut out the stars from the star packet. Students will
glue/tape the stars in the correct locations on their H-R diagram.
8. Students will answer the questions at the end of the activity. Students
will turn in their H-R diagram and their answers to the questions at the
conclusion of the activity.
EXAMPLE
Hertzsprung-Russell Diagram
Absolute Brightness
0
1
2
3
4
5
6
50,000 oC
20,000 oC
10,000 oC
6,000 oC
Surface Temperature oC
5,000 oC
3,000 oC
Name: __________________________
Hertzsprung-Russell Activity Questions
Use the H-R diagram that you created to answer the questions below.
Answer the questions in complete sentences.
1. Which star is a red supergiant that is very bright?
2. Which star is dim with a surface temperature of 30,000 oC?
3. Are the brightest stars always the hottest? Explain.
4. What is the relationship between surface temperature and brightness
for main sequence stars? Use pages 132-133 in the book for help.
5. Could a star’s placement on the Hertzsprung-Russell diagram change?
6. The star Procyon B has a surface temperature of 6,600 oC and its
absolute brightness is 13.04. The sun has an absolute brightness of
4.8. What type of star is Procyon B? Use the H-R diagram on page
132 for help.
7. Star A and B have about the same apparent brightness, but Star A is
about twice as far from Earth as Star B. Which star has the greater
absolute brightness? Explain.
8. Arrange the stars on the H-R diagram that you created from dimmest
to brightest by name.