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Stars: HR Diagram & Classification
Resource ID#: 160297
Primary Type: Lesson Plan
This document was generated on CPALMS - www.cpalms.org
In this Model Eliciting Activity (MEA), students will categorize a list of stars based on absolute
brightness, size, and temperature. Students will analyze astronomical data presented in charts and
plot their data on a special graph called a Hertzsprung-Russell Diagram (H-R Diagram). Using this
diagram, they must determine the proper classification of individual stars. Using their data analysis,
students completing this MEA will develop two short essay responses to a professional client
indicating which stars are Main Sequence Stars and which ones are White Dwarfs, Giants, or
Supergiants.
Subject(s): Mathematics, English Language Arts, Science
Grade Level(s): 8
Intended Audience: Educators
Suggested Technology: Computer for Presenter, Internet Connection, Interactive Whiteboard, LCD
Projector
Instructional Time: 3 Hour(s)
Keywords: Star, hr diagram, stellar, luminosity, brightness, properties, astronomy, space, galaxy,
light, magnitude, sun, life, cycle, supergiant, white dwarf, main sequence
Instructional Component Type(s): Lesson Plan, Model Eliciting Activity (MEA) STEM Lesson
Resource Collection: FCR-STEMLearn MEA 2016
ATTACHMENTS
HR Diagram-Complete-Teacher.jpg
Letter_1.docx
Letter_2.docx
Data_1.docx
Data_2.docx
Data_Teacher.docx
Response_Template.docx
Rubric.docx
Stars-HR-Diagram-Student.jpg
LESSON CONTENT

Lesson Plan Template:
Model Eliciting Activity (MEA)

Formative Assessment
The comprehension readiness questions and guiding questions can be used as formative assessment (for
questions, see the Readiness Questions section below). Readiness Questions will indicate whether the students
understand the problem and the problem context.

Feedback to Students
Feedback to students is provided throughout the lesson. Please view the provided lesson plan in the
"Instructional Suggestions" section for more details.

Summative Assessment
Use the attached Rubric.

Learning Objectives
In this MEA, students will:
o
o
o
o
o

describe physical properties of stars such as luminosity, temperature, color, and size.
compare and classify stars as main sequence, white dwarf, giant, or supergiant based on their physical
properties.
integrate the quantitative information presented in both a data table and linear graph and properly
express their correlation in words.
describe the functional relationship between the quantities of luminosity and temperature by plotting
and analyzing a graph of this relationship.
produce a clear and coherent written response appropriate for a professional scientific audience.
Prior Knowledge
Students should:
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o
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be familiar with the most basic properties of stars
understand that stars produce light and heat, and that these quantities can be measured
be familiar with graphing lines
understand scientific notation in order to properly use the data chart and plot the data
Instructional Suggestions
This lesson is intended to be completed in 1.5 block days (approximately 3 hours). The lesson plan
indicated below is presented in a time-oriented breakdown:
1.
2.
3.
4.
5.
(0-10 min.) Begin class with a quick introduction/review of stars. Go over properties such as absolute
brightness (luminosity), color, and temperature. The BrainPop "Stars" or BBC Bitesize GCSE "Life
Cycles of Stars" activity videos are excellent sources for a quick review. If you do not have access to
these resources, a class discussion, reading out loud from the textbook, or other video review would be
appropriate.
(11-20 min.) Complete the BrainPop or BBC Bitesize post-lesson quiz as a class. Be sure to define the
following words with the class: absolute brightness (luminosity), color, temperature, H-R Diagram,
Main Sequence, White Dwarf, Red Giant.
(21-25 min.) Introduce theMEA lesson concept: Your students' help has been requested byNASA in
order to help them properly categorize stars they have been observing. Students must analyze a data
chart with information about the stars and properly plot the star's location on the H-R Diagram.
Depending on the location on the H-R Diagram, the students will determine the type of star (Main
Sequence, White Dwarf, Giant).
 Arrange students in groups of 3-4 to prepare for the project (it may be helpful to have
predetermined groups ready).
(26-30 min.) Pass out the Client Letter 1, Data Set 1, and H-R Diagram sheets to each group. Allow
students in each group to read the client letter.
(31-40 min.) Data Set 1: Instruction and Example
 Use the Teacher's H-R Diagram to assist. Go over all of the columns listed in Data Set 1 with
the class. Define each term and show how it relates to the H-R Diagram. Use the data from
the Sun as an example of how to place it properly on the H-R Diagram. It is strongly advised
to show placement on the H-R Diagram on a projector so the whole class can see how to do
so properly.
 Each group should plot the point of the Sun on their own diagram.
 Review each of the types of stars as indicated on the H-R Diagram.
6.
7.
8.
9.
(41-50 min.) Discuss the Readiness Questions as a class to be sure the students understand the
assignment. They will be submitting three items for this portion of the activity. Explain that they will
be completing the following three activities:
 They must plot a point for each star in the proper location of the H-R Diagram.
 They must properly answer the 5 guiding questions (see section below) in complete
sentences. Either hand them out to each student or project the questions so that students can
see them.
 They must write a Response Letter indicating the classification type of each star (as one of
the following: White Dwarf, Main Sequence, Red Giant, Blue Giant, Supergiant). The
Response Template may help students organize their thoughts and make grading faster, but if
you wish to focus on student writing skills, spelling, and grammar, then you may wish to
have them respond in an essay without using the template.
(51-90 min.) Once the students understand the instructions for the assignment (step 6), allow them to
work in their groups to complete these three activities. It is strongly suggested that you move from
group to group to help students with the Guiding Questions, as the proper answers to these questions
represent the main subject matter of the lesson. Students having trouble plotting the points on the
diagram will likely benefit from working on the questions first. These questions should also be used as
guidelines to help the students write their response letters.
(91-110 min.) Collect and Review
 Collect all of the completed work and other materials from each group (H-R Diagram,
Response Letter, Guiding Questions, Data Chart 1). These will be graded by the teacher at a
later time (note: do not grade the H-R Diagram until the students have completed the full
MEA parts 1 and 2).
 Using the projector or smartboard, review all of the information with the entire class. You
essentially want to do the whole activity with everyone at this point, calling on students from
different groups and having them explain how and why they made their selections.
 First, go over the Data Chart and H-R Diagram. Show where each star should be located. If
using an interactive board, you can have members from each group plot the location on your
smartboard. Ask students to describe the location of the star based on its color, temperature,
and brightness. After they place their star, ask them what classification they gave it and why.
Do not display the Teacher's H-R Diagram because it has additional stars the students have
not seen yet that will be used in part 2.
 Review the 5 guiding questions with the class. Have them explain their answers by relating
them to the data chart and H-R Diagram whenever possible.
(110-115 min.) Wrap-up and final questions: Discuss any common errors or problems that students
may have had. Respond to any other questions the class may have about today's lesson.
Block Day 2
10. (0-10 min.) Inform your students that you have heard back fromNASA about their stellar classification
work.NASA is pleased with your results and has a few more stars they would like you to classify.
 Arrange your students in the same groups from the first part of this MEA. Pass out Client
Letter 2 and Data Chart 2. Allow students in each group to read the client letter.
 Pass out the previously completed H-R Diagram 1 to the proper groups. Students will add the
new stars to this diagram. Note: You may also pass out Data Chart 1 to any of the groups that
may have improperly completed the H-R Diagram on day 1. They could be allowed to fix the
location of the older stars without penalty.
11. (11-20 min.) As a class, quickly review the data on Data Chart 2. Prompt the students to explain the
classification of stars in their own words. The Sun has been provided again in Data Chart 2 to serve as
an example. Have the class describe the color, temperature, brightness, and classification of the Sun
(Main Sequence) using its location on the H-R Diagram.
12. (21-50 min.) In groups, students will be completing two activities:
 Plot all of the stars on the H-R Diagram (there will be 13 stars in total on the finished
diagram).
 Write a Response Letter indicating the classification of the five new stars provided.
 Travel between student groups to assist them with proper classification. If they are
having trouble, you may prompt them with the guiding questions from day 1, or
others similar to these. Note: Even though students do not have to complete the
Guiding Questions in this second portion of the lesson, you may still wish to provide
them on your projector to remind the students about the important details.
13. (51-70 min.) Collect and Review
 Collect all of the completed work and other materials from each group (H-R Diagram,
Response Letter, Data Chart 2). These will be graded by the teacher at a later time. Using
your projector or smartboard, review all of the information with the entire class. Call on
students from different groups and have them explain how and why they made their
selections. You may project the Teacher's H-R Diagram on the overhead to show the proper
position of each of the stars.
 Discuss the following information:
 Some of the stars will not fit perfectly into any of the categories. The classification
of these stars should be an interesting point of discussion. How do you think
scientists deal with situations like this?
 Rigel A and Deneb are far from everything, but should definitely be considered
"Giants." Some students may call them "White Giants" or "Yellow Giants" which
would be a clever new classification. Any classification involving "Giant" should be
accepted as correct.
 Algol A and Wolf 359 are both slightly outside of the drawn "main sequence" stars,
they are both in-line enough to be classified as such.
 Spica is not quite into the Blue Giants, but is also reasonably far from the Main
Sequence stars. What did you call it?
14. (71-115 min.) You have successfully completed the MEA. This additional time may be used for
accommodations or additional lesson material as desired. Review of previous topics could be done as
well. A video about stars could serve as a fun wrap-up activity. The Discovery Education video called
How the Universe Works: Extreme Stars, uploaded byBenold Science (41:42 length) works well for
this purpose. There are also many other videos about stars available from this website.
 If you will be moving from stars in general to the particulars of the Sun after this lesson, this
is a good opportunity for a video, lesson, or activity about the Sun. NOVA's video Secrets of
the Sun, uploaded by BradfordCB (52:43) works well for this purpose.

Supplemental Reading
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The BBC Bitesize and BrainPop websites have additional text-based information that students may
read and review on their own time.
The websites used to create the Data Charts also have a vast array of written information. The NASA
website has many different activities for students and teachers alike.
Guiding/reflective Questions
0.
1.
2.
3.
4.
What happens to the temperature as you move to the left side of the H-R Diagram?
According to this H-R Diagram, what are the characteristics of a White Dwarf star?
How does the color of a star relate to its temperature? Explain your answer using colors from the
diagram.
Describe the position of Main Sequence stars on this graph. How can you tell if a star is a Main
Sequence star?
Where do very bright stars get placed on the H-R diagram? What about a very bright star with a very
low temperature? What color would that star be?
Suggested responses in quick-response form:
5.
6.
7.
The temperature increases as you move to the left of the H-R Diagram.
A white dwarf star is very dim (low luminosity) but also very hot.
The color of stars changes as the temperature changes. Stars with lower temperatures are red and the
hottest stars are blue. Yellow stars have a medium temperature.
8.
9.

The main sequence stars form a line from the top left to bottom right corner of the H-R Diagram. Any
stars that are close to this line are probably main sequence stars.
Very bright stars will be close to the top of the H-R Diagram. A very bright star with a low
temperature would appear as a red star in the top right hand corner of the H-R Diagram.
Reading Passage 1
See attached Letter 1.
Attention Young Astronomers,
The Natural Aeronautics & Space Administration (NASA) is the nation’s leading expert in astronomy and
space exploration. We are currently developing a catalogue of stars to be used in future research projects. There
are billions upon billions of stars in our galaxy alone, so this is a massive undertaking.
With so many stars to be catalogued, we are writing to request your assistance in organizing and classifying
some of the stars we have discovered. Using a Hertzsprung-Russell Diagram, or H-R Diagram, we need you to
classify the stars based on their luminosity and temperature. Each star should be placed into one of the
following categories: Main Sequence, Giant, Supergiant, or White Dwarf.
You have been provided with a list of 8 stars. Use the information in the data chart to properly place each star
on the H-R Diagram. You should be able to classify the type of star based on its position on the diagram. The
radius of each star compared to the radius of our Sun has also been provided to help you with your stellar
classification.
Please write us back and tell us the name of each star along with the stellar classification (type of star) you
determined. In your response letter, please include a step-by-step explanation of how you classified each of the
stars provided. Please be especially clear with your explanation of classifications for any stars that were outside
of the normal area for stars of that type. We would also like a copy of your completed H-R Diagram with the
data points for each star labeled appropriately. Thank you for your help!
Sincerely,
G. Jetson
Head of Stellar Observation, NASA

Readiness Questions
0.
1.
2.
3.
Who is the client?
What is the client asking your team to do?
What do you have to do with the 5 questions?
What things do you need to include in your response letter?
Suggested responses:
4.
5.
6.
Our client is NASA.
Our client wants us to complete an H-R Diagram and classify the stars in a data chart as either Main
Sequence, Giant, Supergiant, or White Dwarf.
We have to answer each of the questions in complete sentences and turn them in at the end of class.
7.

In our response, we need to state the name and classification of each star, our complete H-R diagram,
and an explanation of why we decided to call a star a certain type if it didn’t exactly match the points
in the diagram.
Data Set 1
See attached Data Sheet 1, Student H-R Diagram, and the Teacher H-R Diagram.

Letter Template 1
See attached Response Template.

Comprehension/readiness questions
See Readiness Questions (above).

Reading Passage 2
See attached Letter 2.
Attention Young Astronomers,
Thank you for completing your first set of stellar classification. We have added the information you have
provided to our database. Since there are so many billions of stars, we have another set for you to classify.
We need you to help classify this short list of 5 new stars using a Hertzsprung-Russell Diagram. The Sun has
also been provided as a 6th star in this group for comparison. Please add these 5 new stars to your previously
completed H-R Diagram. You will once again be classifying these stars based on their luminosity and
temperature. The radius of each star compared to the radius of our Sun has also been provided to help you with
your stellar classification. Each star should be placed into one of the following categories: Main Sequence,
Giant, Supergiant, or White Dwarf. You should be able to classify each type of star based on its position on the
diagram.
As you did before, please write us back and tell us the name of each star along with the stellar classification you
determined. Please follow the same classification procedure that you used in your first trial to help you
complete this latest request. If you had to make any changes to your classification procedure, please clearly
explain why you had to do so, and explain the changes. We would also like a copy of your completed H-R
Diagram with the data points for all 13 stars from both lists labeled appropriately. Thank you for your help!
Keep looking up!
Sincerely,
G. Jetson
Head of Stellar Observation, NASA

Data Set 2
See attached Data Sheet 2. At this point, the Student H-R Diagram should already have points from the
previous activity listed on it. Students will use the same diagram on Day 2, adding additional points.

Letter Template 2
See attached Response Template.

Additional Instructions or Materials
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A Teacher H-R Diagram has been provided with all of the information for the student data charts, as
well as additional information to be used as desired.
Discovery Education has a video called How the Universe Works: Extreme Stars, uploaded by
Benold Science (41:43), that is very engaging. There are also many other videos about stars available
from this website.
If you will be moving from stars in general to the particulars of the Sun after this lesson, this is a good
opportunity for a video, lesson, or activity about the Sun. NOVA has an excellent 53 minute video
available online called Secrets of the Sun, uploaded by BradfordCB (52:43).
Reflection question 2
See Instructional Suggestions (above).
ACCOMMODATIONS & RECOMMENDATIONS

Accommodations:
The MEA concludes with approximately 1 hour of class time available if using block scheduling. This
additional time may be used for accommodations or additional lesson material as desired. Review of previous
topics could be done as well. A video about stars could serve as a fun wrap-up activity.

Extensions:
For advanced classes, this lesson may also be expanded to include a research project. The students' data charts
may be cleared of all of the data besides the name of the stars. Students would then have to go online and
search for the information to properly fill out the data chart before they could place the data points on the H-R
Diagram. Note that, if you chose this option, much of the data the students will find will vary from website to
website. I had to spend a good deal of time compiling a small amount of data from one site to another and
averaging data to make the student chart simple to read and use. This would likely require at least 1 additional
hour of class time, but probably 2 to finish the project with good results.


Suggested Technology: Computer for Presenter, Internet Connection, Interactive Whiteboard, LCD Projector
Special Materials Needed:
o
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A color printer is required to properly print out the H-R Diagram.
If you wish to complete the advanced lesson extension where students complete the data chart
independently, you will require a computer with an Internet connection for each group of students.
A computer with an Internet connection and a projector is required to play the BrainPop and BBC
videos for your class. You will also benefit from being able to project the H-R Diagram and add data
points using an interactive board.
If you have time and the computers available, students may be able to explore these videos and
websites individually. This is only suggested for advanced classes or students with a fairly high level
or self discipline.
Additional Information/Instructions
By Author/Submitter
Data for the table was acquired using the following websites:


Wikipedia, "List of most luminous stars"
Bright Stars Photo Gallery
H-R Diagram image obtained from:

Space Book: H-R Diagram
SOURCE AND ACCESS INFORMATION
Contributed by: Daniel Brillat
Name of Author/Source: Daniel Brillat
District/Organization of Contributor(s): Miami-Dade
License: CPALMS License - no distribution - non commercial
Related Standards
Name
LAFS.68.RST.3.7:
SC.8.E.5.5:
MAFS.8.F.2.5:
Description
Integrate quantitative or technical information expressed in words
in a text with a version of that information expressed visually (e.g.,
in a flowchart, diagram, model, graph, or table).
Describe and classify specific physical properties of stars: apparent
magnitude (brightness), temperature (color), size, and luminosity
(absolute brightness).
Describe qualitatively the functional relationship between two
quantities by analyzing a graph (e.g., where the function is
increasing or decreasing, linear or nonlinear). Sketch a graph that
exhibits the qualitative features of a function that has been
described verbally.