science grade 08 unit 11 exemplar lesson 02: classifying stars1. group students into pairs, and...
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Grade 8
Science
Unit: 11
Lesson: 02
Suggested Duration: 7 days
Science Grade 08 Unit 11 Exemplar Lesson 02: Classifying StarsScience Grade 08 Unit 11 Exemplar Lesson 02: Classifying Stars
This lesson is one approach to teaching the State Standards associated with this unit. Districts are encouraged to customize this lesson by
supplementing with district-approved resources, materials, and activities to best meet the needs of learners. The duration for this lesson is only a
recommendation, and districts may modify the time frame to meet students’ needs. To better understand how your district may be implementingCSCOPE lessons, please contact your child’s teacher. (For your convenience, please find linked the TEA Commissioner’s List of State Board of
Education Approved Instructional Resources and Midcycle State Adopted Instructional Materials.)
Lesson Synopsis
In this lesson, students describe components of the universe and use the Herztsprung-Russell diagram to classify stars. They will identify the Sun as
a medium-sized star near the edge of a disc-shaped galaxy of stars and understand that it is thousands of times closer to Earth than other stars.
TEKS
The Texas Essential Knowledge and Skills (TEKS) listed below are the standards adopted by the State Board of Education, which are required by
Texas law. Any standard that has a strike-through (e.g. sample phrase) indicates that portion of the standard is taught in a previous or subsequent
unit. The TEKS are available on the Texas Education Agency website at http://www.tea.state.tx.us/index2.aspx?id=6148.
8.8 Earth and space. The student knows characteristics of the universe. The student is expected to:
8.8A Describe components of the universe, including stars, nebulae, and galaxies, and use models such as the
Herztsprung-Russell diagram for classification.
Readiness Standard
8.8B Recognize that the Sun is a medium-sized star near the edge of a disc-shaped galaxy of stars and that the Sun is
many thousands of times closer to Earth than any other star.
Supporting Standard
Scientific Process TEKS
8.2 Scientific investigation and reasoning. The student uses scientific inquiry methods during laboratory and field
investigations. The student is expected to:
8.2E Analyze data to formulate reasonable explanations, communicate valid conclusions supported by the data, and
predict trends.
8.3 Scientific investigation and reasoning. The student uses critical thinking, scientific reasoning, and problem solving to
make informed decisions and knows the contributions of relevant scientists. The student is expected to:
8.3A In all fields of science, analyze, evaluate, and critique scientific explanations by using empirical evidence, logical
reasoning, and experimental and observational testing, including examining all sides of scientific evidence of
those scientific explanations, so as to encourage critical thinking by the student.
8.3B Use models to represent aspects of the natural world such as an atom, a molecule, space, or a geologic feature.
8.3C Identify advantages and limitations of models such as size, scale, properties, and materials.
8.3D Relate the impact of research on scientific thought and society, including the history of science and
contributions of scientists as related to the content.
8.4 Scientific investigation and reasoning. The student knows how to use a variety of tools and safety equipment to
conduct science inquiry. The student is expected to:
8.4A Use appropriate tools to collect, record, and analyze information, including lab journals/notebooks, beakers, meter sticks, graduated
cylinders, anemometers, psychrometers, hot plates, test tubes, spring scales, balances, microscopes, thermometers, calculators,
computers, spectroscopes, timing devices, and other equipment as needed to teach the curriculum.
GETTING READY FOR INSTRUCTION
Performance Indicators
Grade 08 Science Unit 11 PI 02
Create a field guide for stars, including our Sun, a supergiant, a giant, a main sequence star, and a dwarf star. Provide a description, relative age and life span, luminosity,
and temperature of each star. Finally, describe how models such as a Hertsprung-Russel diagram can be used for classification.
Standard(s): 8.2E , 8.8A , 8.8B
ELPS ELPS.c.1C , ELPS.c.2C , ELPS.c.5B
Key Understandings
Last Updated 06/03/13 page 1 of 32
All stars are not the same in size, age, and temperature.
— How are galaxies classified?— Where is our Sun located in the Milky Way galaxy?— What characteristics are used to classify stars?— How are stars classified on an HR diagram?— Once a star has been identified as a main sequence star, will it always remain in that area on an HR diagram?— What factor determines the life cycle a star will have?— How is the life cycle of a main sequence star different from the life cycle of a massive star?— How is our Sun classified as a star?— What star is closest to Earth?
Vocabulary of Instruction
star
protostar
main sequence star
universe
red giant star
red supergiant star
white dwarf star
neutron star
black dwarf star
black hole
galaxy
stellar nebula
planetary nebula
elliptical galaxy
spiral galaxy
irregular galaxy
barred-spiral galaxy
luminosity
Hertzsprung-Russell diagram
absolute magnitude
apparent magnitude
Materials
tape or glue (per class)
flashlights (identical basic, 2 per teacher demonstration)
flashlight (bright LED bulb(s), 1 per teacher demonstration)
Group HR Diagrams (see Advance Preparation, 1 per group)
paper (butcher, white, 1 sheet per group)
marker (per teacher)
tape (masking, per group)
colored pencils (blue, yellow, orange, and red, 1 per student)
pencil (1 per student)
paper (plain, multiple sheets per class)
paper (various per class)
colored pencils (per class)
Attachments
All attachments associated with this lesson are referenced in the body of the lesson. Due to considerations for grading or student assessment,
attachments that are connected with Performance Indicators or serve as answer keys are available in the district site and are not accessible on the
public website.
Teacher Resource: Galaxies and Stars Cards (see Advance Preparation, 1 set per group)
Handout: Galaxies (1 per student)
Teacher Resource: Galaxies KEY
Handout: Galaxies and Stars Questions (1 per student)
Teacher Resource: Galaxies and Stars Questions KEY
Teacher Resource: PowerPoint: Galaxies and Stars
Teacher Resource: Human Life Cycle Cards (see Advance Preparation, 1 set per pair)
Teacher Resource: Star Life Cycle Cards (see Advance Preparation, 1 per group)
Handout: Life Cycle of Stars Graphic Organizer (1 per student)
Teacher Resource: Life Cycle of Stars Graphic Organizer KEY
Teacher Resource: PowerPoint: Star Life Cycle
Handout: Galaxies and Stars (1 per student)
Teacher Resource: Galaxies and Stars KEY
Teacher Resource: Power Point: Star Classification
Teacher Resource: H-R Diagram Samples
Teacher Resource: Power Point: H-R Diagram
Handout: Stars from Afar (1 per student)
Teacher Resource: Stars from Afar KEY
Grade 8
Science
Unit: 11
Lesson: 02
Suggested Duration: 7 days
Last Updated 06/03/13 page 2 of 32
Teacher Resource: Stars from Afar Graph KEY
Teacher Resource: Performance Indicator Instructions KEY (1 for projection)
Resources
None Identified
Advance Preparation
1. Prior to Day 1:
Print on cardstock, laminate, cut apart, and bag the cards of the Teacher Resource: Galaxies and Stars Cards. You will need one set per
group.
Arrange for student computer/Internet use for Days 1, 2 and 7.
2. Prior to Day 2:
Print on cardstock, laminate, cut apart, and bag the cards of the Teacher Resource: Human Life Cycle Cards. There are four sets per page,
and you will need one set per pair of students.
Print on cardstock, laminate, cut apart, and bag the cards of the Teacher Resource: Star Life Cycle Cards. There are three sets per page,
and you will need one set per group.
3. Prior to Day 5:
Assemble Star Sets for star classification activity. Print on cardstock, laminate, cut apart, and bag Teacher Resource: Power Point: Star
Classification. You will need one set per group.
The following site may be used to develop the background and connection between the visible spectrum and the color and temperature of
stars.
Create group H-R diagrams for star classification activity. Use one large piece of white butcher paper for each diagram. See the Handout:
Stars from Afar page 3 for an example. Laminate to increase durability. You will need one diagram per group.
4. Prior to Day 6: Perform a web search for an approved interactive HR diagram. You may find it helpful to include the terms “aspire and HRinteractive” in your search.
5. Prepare attachment(s) as necessary.
Background Information
This unit bundles student expectations that address components and characteristics of the universe. Students learn that stars and galaxies are part of the universe and how
they can be classified by their characteristics.
Prior to this unit, in Grade 8, students studied the effects resulting from cyclical movements of the Sun, Earth, and Moon. Cycles within the Earth, Sun, and Moon systems are
studied as students learn about seasons, tides, and lunar phases.
During this lesson, students will study the components of the universe. This will be the first time students investigate the universe beyond our solar system, including the
properties of components in the universe. They also recognize that the Sun is a medium-sized star near the edge of a disc-shaped galaxy of stars and will describe
components of the universe, including stars, nebulae, and galaxies and use models such as the Herztsprung-Russell diagram for classification.
STAAR Note:
Readiness Standard (8.8A), the components of the universe and models such as the Herztsprung-Russell diagram, Supporting Standard (8.8B), recognition of the sun as a
medium-sized star near the edge of a disc-shaped galaxy, and Supporting Standard (8.8C), exploring how different wavelengths of the electromagnetic spectrum, are used
to gain information about distances and properties of components in the universe will be assessed under Reporting Category 3: Earth and Space on the STAAR Grade 8
Science Assessment.
INSTRUCTIONAL PROCEDURES
Instructional Procedures
ENGAGE – Galaxies and Stars Cards
Notes for Teacher
NOTE: 1 Day = 50 minutes
Suggested Day 1
1. Divide the class into groups of four.
2. Distribute the Teacher Resource: Galaxies and Stars Cards to each group.
3. Instruct students to graphically organize the cards in an order that makes sense to
them.
4. Monitor the groups, pre-assessing and making note of any misconceptions to clarify
throughout the lesson.
5. As you monitor, ask each group to justify why they placed their cards in the order
displayed.
Attachments:
Teacher Resource: Galaxies and Stars Cards
(see Advance Preparation, 1 set per group)
Instructional Note:
Consider using cards throughout the lesson as formative
assessment.
Grade 8
Science
Unit: 11
Lesson: 02
Suggested Duration: 7 days
Last Updated 06/03/13 page 3 of 32
6. Collect card sets.
7. Explain to students that this is a pre-assessment and they will have the opportunity
to learn the answers throughout the lesson.
EXPLORE/EXPLAIN – Galaxies Suggested Days 1 (continued) and 2
1. Group students into pairs, and distribute the Handout: Galaxies to each student.
2. Instruct students to work in pairs to use computers/Internet or other classroom
resources to research the types of galaxies and complete their handout.
3. Draw a triangle with the points labeled A, B, and C on the board. Instruct students to
draw the triangle on the back of their handout and label the points A, B, and C.
4. Instruct students to find an A, B, and C partner and have them sign their name on
their partner’s page next to the letter on the triangle. Give students about 3–5minutes to find their partners. Students should return to their seats as soon as they
have acquired a partner for all three points.
5. Instruct students to do the following at your signal:
Meet with partner A, and share/compare irregular galaxies.
Meet with partner B, and share/compare elliptical galaxies.
Meet with partner C, and share/compare spiral galaxies.
6. Allow students 2–3 minutes to share with each partner before giving the signal tofind their next partner.
7. Distribute the Handout: Galaxies and Stars Questions to each student. Instruct
students to answer questions as you progress through the slides (only slides 1–6).Explain to students that they will only complete what they can for now and they will
revisit the questions to elaborate later in the lesson.
8. Project the Teacher Resource: PowerPoint: Galaxies and Stars, and facilitate a
discussion as you progress through the Power Point (only slides 1–6). Pause toallow students time to answer questions.
9. Instruct students to check their Galaxies handout answers as you progress through
the Power Point and make any necessary modifications (only slides 1–6). Pause toallow students time to check their answers.
10. Instruct students to affix their Galaxies handouts and Galaxies and Stars
Questions to their notebooks.
11. Ask students to respond to the following reflective questions in their notebooks.
Ask:
How are galaxies classified?
Where is our Sun located in the Milky Way Galaxy?
Materials:
tape or glue (per class)
Attachments:
Handout: Galaxies (1 per student)
Teacher Resource: Galaxies KEY
Handout: Galaxies and Stars Questions (1 per
student)
Teacher Resource: Galaxies and Stars
Questions KEY
Teacher Resource: PowerPoint: Galaxies and
Stars
Instructional Note:
This is the first experience students have had exploring space
beyond our solar system.
Science Notebooks:
Students affix their Galaxies handouts and Galaxies and Stars
Questions to their notebooks and respond to the reflective
questions.
EXPLORE/EXPLAIN – Life Cycle of a Star Suggested Days 2 (continued), 3, and 4
1. Divide the class into pairs.
2. Distribute the card sets from Handout: Human Life Cycle to each group.
3. Instruct students to sequence the cards in the correct order of a human life cycle:
infant, toddler, child, teen, adult, elderly, and death. Monitor the sequences students
create.
4. Ask/Say:
What might the Human Life Cycle sequencing activity have to do with
stars? Accept answers.
If galaxies are made up of a collection of stars, dust, and gas, then where
do these stars come from? Accept answers.
Inform students that stars undergo a life cycle that could be compared to
a human life cycle. To avoid building a misconception, be sure students
understand that a star has never been alive. Stars will go through a
sequential cycle and then cease to exist.
Materials:
tape or glue (per class)
Attachments:
Teacher Resource: Human Life Cycle Cards (see
Advance Preparation, 1 set per pair)
Handout: Galaxies and Stars Questions (from
previous activity)
Teacher Resource: Galaxies and Stars
Questions KEY (from previous activity)
Teacher Resource: PowerPoint: Galaxies and
Stars (from previous activity)
Teacher Resource: Star Life Cycle Cards (see
Grade 8
Science
Unit: 11
Lesson: 02
Suggested Duration: 7 days
Last Updated 06/03/13 page 4 of 32
A star’s life cycle depends on its mass.
5. Ask students to open their notebooks to the Handout: Galaxies and Stars
Questions (previously distributed and affixed).
6. Project the Teacher Resource: PowerPoint: Galaxies and Stars, and discuss slides
7–9 with students. Instruct students to watch for underlined words or phrases as theycontinue to answer questions. Monitor students’ answers for accuracy as theycomplete the questions.
7. Divide the class into groups of four, and distribute card sets from Handout: Star Life
Cycles to each group.
8. Instruct students to place the cards in the order that they think is an appropriate
sequence of the life cycle of a star (protostar, main sequence, red giant, and white
dwarf) or (red supergiant, supernova, and neutron star). Point out that the life cycle
may go in two different directions, based on the mass of a star and all stages may
not be represented in the set of cards. Monitor students as they sequence cards.
9. Ask for student volunteers from each group to explain the reasoning behind their
group’s sequencing. Acknowledge all answers, but do not correct at this point.Collect the cards.
10. Project the Teacher Resource: PowerPoint: Galaxies and Stars and discuss slides
10–18 with students. Instruct students to watch for underlined words or phrases asthey continue to answer questions. Remind students that they will still have more
time to work on and revise questions later in the lesson.
11. Post the following analogy of a star to the human life cycle on the board: protostar
(infant), main sequence like our Sun (toddler through teen), red giant/supergiant
(adult through middle age); and white dwarf/black hole (old age and death). Discuss
each stage and how the analogy could be made.
12. Distribute the Handout: Life Cycle of Stars Graphic Organizer to each student.
13. Project the PowerPoint: Star Life Cycle. Facilitate a discussion through questioning,
and instruct students to complete their Life Cycle of Stars Graphic Organizers
and finish completing their Galaxies and Stars Questions as you progress
through the slides. Monitor students as they finish answering the questions.
14. Ask for volunteers to share their completed graphic organizers and answers to the
questions. Address any misconceptions. Allow students to correct their handouts, if
needed.
15. Instruct students to affix their graphic organizers to their notebooks.
16. Distribute the Handout: Galaxies and Stars to each student. Instruct them to
complete the handout and to submit it as a formative assessment. Allow students to
use their notebooks as a resource.
Advance Preparation, 1 set per group)
Handout: Life Cycle of Stars Graphic Organizer
(1 per student)
Teacher Resource: Life Cycle of Stars Graphic
Organizer KEY
Teacher Resource: PowerPoint: Star Life Cycle
Handout: Galaxies and Stars (1 per student)
Teacher Resource: Galaxies and Stars KEY
Instructional Notes:
Students have little to no experience with life cycles of stars.
This portion of the lesson contains multiple transitions. Plan
ahead for strategies that will minimize movement and loss of
instructional time.
Misconceptions:
Students may think the Sun is not a star.
Students may think stars are different colors
because of distance, size, or different matter.
Students may think the Sun (or other stars) will
never change and exist forever.
STAAR Notes:
Readiness Standard (8.8A), the components of the universe and
models such as the Herztsprung-Russell diagram, and
Supporting Standard (8.8B), recognition of the sun as a medium-
sized star near the edge of a disc-shaped galaxy will be assessed
under Reporting Category 3: Earth and Space on the STAAR Grade
8 Science Assessment.
Check For Understanding:
Students complete the Handout: Galaxies and Stars.
Science Notebooks:
Students affix their graphic organizers to their notebooks.
ENGAGE/EXPLORE/EXPLAIN – Star Differences Suggested Days 4 (continued) and 5
1. Write the terms Absolute Magnitude and Apparent Magnitude on the board. Ask
for student volunteers to describe what these terms mean. Acknowledge all answers.
2. Explain to students that the term absolute magnitude refers to how bright a star
would look if it were 32.6 light years away from the Earth. Absolute magnitude is the
true brightness of a star. Apparent magnitude is how bright the star looks in the sky
from Earth. Instruct students to write these terms and meanings in their notebooks.
3. Dim the lights in the classroom.
4. Put two equally bright flashlights next to each other on a table in the front of the
room, and turn on the flashlights.
5. Students should be on the opposite side of the darkened room to view the table with
the two flashlights. Inform students that the lights represent two stars.
6. Refer back to the terms absolute magnitude and apparent magnitude.
Say:
Would you agree or disagree to the following statement: The light
coming from the two flashlights has the same absolute magnitude and
apparent magnitude when they are placed side by side. (Agree)
7. Move one of the two flashlights closer to the students.
Materials:
flashlights (identical basic, 2 per teacher
demonstration)
flashlight (bright LED bulb(s), 1 per teacher
demonstration)
Instructional Notes:
It is not necessary for students to know the technical definitions.
The idea that astronomers have agreed on a standard unit of
measurement is important, not the specifics of a parsec.
Science Notebooks:
Students record terms and their meanings in their notebooks.
Grade 8
Science
Unit: 11
Lesson: 02
Suggested Duration: 7 days
Last Updated 06/03/13 page 5 of 32
Say:
Would you agree or disagree to the following statements:
The apparent magnitudes of the lights have not changed. (Disagree)
The absolute magnitude of the lights has not changed. (Agree)
The apparent magnitude of the closer flashlight is now greater, but the
absolute magnitude of both lights remained the same.
8. Replace one of the flashlights with a brighter flashlight, and place them next to each
other. Instruct the students to view the model.
Ask:
How are the absolute magnitude and apparent magnitude affected? (The
absolute magnitude of the brighter flashlight is more, but the apparent magnitude
is greater for the brighter flashlight.)
9. Now, move the brighter flashlight closer to the students. Instruct the students to view
the model.
Ask/Say:
How are the absolute and apparent magnitude affected? (The absolute
magnitude is the same, but the apparent magnitude of the brighter flashlight has
become greater.)
Refer to the definition of a star’s absolute magnitude.Absolute magnitude is the brightness the star has if it is measured at a
standard distance from Earth. In astronomy, this distance has been
agreed to be 10 parsecs. (A parsec is equal to 3.26 light years. Multiply 10
parsecs by 3.26 ly, and it equals the 32.6 ly distance in the definition you wrote
earlier. The idea that a parsec is a unit of measurement that astronomers have
agreed to be a standard is enough for students to know.)
EXPLORE/EXPLAIN – Classifying Stars Suggested Day 5 (continued)
1. Project the Teacher Resource: PowerPoint: Star Classification (see
Advance Preparation), and show students the materials that will they will
be working with in this exploration. Point out the example slide 1 so
students will understand what the numbers represent.
2. Explain to students that they will be asked to observe their stars and
determine four different ways they could be classified or sorted.
3. Divide the class into groups of 4–5, and distribute Star to each group Sets(see Advance Preparation and Instructional Notes).
4. Allow students time to observe their stars and determine four different
ways they could be classified or sorted.
5. Ask students to share with the class their ideas for classifying or sorting
the stars.
6. Once it is determined that the stars can be classified by color, size (S, M,
L), temperature, and luminosity, instruct students to work with their groups
to classify (sort) their stars in these four manners.
7. Monitor and assist groups as needed.
8. Write the following on the board:
Describe the patterns you saw when you classified the stars in
the four different manners.
9. Instruct students to describe the patterns for each manner of classification
in their notebooks.
10. Facilitate a discussion on the connection between the visible spectrum
and the colors and temperatures of stars (see Advance Preparation).
11. Introduce students to the basics of H-R diagrams, projecting a sample of
Hertzsprung-Russell diagrams from the Teacher Resource: H-R Diagram
Samples. Explain that there are variations in how H-R diagrams are
displayed, but they all show the same basic information.
Say:
Materials:
Group HR Diagrams (see Advance Preparation, 1 per group)
paper (butcher, white, 1 sheet per group)
marker (per teacher)
tape (masking, per group)
Attachments:
Teacher Resource: Power Point: Star Classification (see
Advance Preparation for Star Sets)
Teacher Resource: H-R Diagram Samples
Instructional Notes:
See the Teacher Resource: Teacher Resource: Power Point: Star
Classification to prepare Star Sets (see Advance Preparation).
The following site may be used to develop the connection between the visible
spectrum and the color and temperature of stars.
http://www.lpi.usra.edu/education/workshops/starsGalaxies/SortingSpectra.pdf
The differences in an H-R diagram and a graph can be confusing for many
students.
Remind students if they should be plotting stars according to luminosity or
absolute magnitude. Point out the differences in the way the two are
represented on the H-R Diagrams.
STAAR Note:
Grade 8
Science
Unit: 11
Lesson: 02
Suggested Duration: 7 days
Last Updated 06/03/13 page 6 of 32
On a Hertzsprung-Russell diagram, each star will be
represented by a dot. The data from many stars are used, so
there are lots of dots.
The position of each dot on the diagram corresponds to the
star's luminosity and/or absolute magnitude, and its
temperature.
The “yaxis” (vertical position) represents the star's luminosityand/or absolute magnitude.
Absolute magnitude moves from positive to negative with the
brighter stars being negative numbers.
Luminosity moves from negative to positive with the positive
numbers being the brighter stars.
The “xaxis” (horizontal position) represents the star's surfacetemperature in Kelvin.
The temperature on the “xaxis” moves from larger to smaller.
(The differences in an H-R diagram and a graph can be confusing for many students.
Although it looks like a graph, it does not function in the typical manner.)
12. Explain to students that they are going to rejoin their groups and plot their
stars on a group H-R diagram (see Advance Preparation) according to
luminosity and temperature. Remind students that they will be using
temperature and luminosity to plot their stars in this activity.
13. Allow students time to plot their stars on their group H-R diagrams.
14. Monitor and assist groups as needed.
15. Facilitate a discussion by asking each group to share answers to the
following questions:
What did you notice about the small stars?
What did you notice about the medium stars?
What did you notice about the large stars?
Which stars have the highest luminosity?
Why do you think the larger stars have more luminosity?
16. Instruct students to answer the questions in their notebooks.
This is the first experience students have had with Herztsprung-Russell
diagrams.
Science Notebooks:
Students describe the patterns that emerged for each manner of classification
and answer the discussion questions in their notebooks.
ELABORATE– Classifying Stars Suggested Day 6
1. Project the Teacher Resource: Power Point: H-R Diagram, and review the process
and tools of star classification.
2. Distribute the Handout: Stars from Afar Lab to each student. Read the instructions
with the students, and answer any questions they may have. Monitor students as
they complete the activity.
3. Note: Preview the two KEYS provided before having students begin the activity. The
student work and KEY do not have to be an exact match, but should be roughly
grouped in the approximate areas.
4. Instruct students to compare the graphs with a partner and discuss any differences.
5. Inform students that:
The yellow-white and blue-white stars have an overlap where stars that
appear white may belong to either group. The white dwarfs are
separated due to their magnitude and temperature.
This is not a complete model. There are billions of stars, and this model
only shows 21 stars. The graph would be very crowded if many more
stars were shown.
Regardless of how many stars were added, they would follow the same
pattern as shown on the graph.
6. Review questions in the follow up questions on page 1 of the Stars from Afar
handout.
Say/Ask:
The H-R diagram was named for Ejar Hertsprung and Henry Russell. Both
saw patterns in star characteristics. The diagram is often abbreviated as
an H-R diagram.
Materials:
colored pencils (blue, yellow, orange, and red, 1
per student)
pencil (1 per student)
Attachments:
Teacher Resource: PowerPoint: H-R Diagram
Handout: Stars from Afar (1 per student)
Teacher Resource: Stars from Afar KEY
Teacher Resource: Stars from Afar Graph KEY
Instructional Notes:
Preview the two KEYS provided before having students begin the
activity. The student work and KEY do not have to be an exact
match, but should be roughly grouped in the approximate areas.
There are differences in the sample H-R diagrams. Students are
not responsible for learning all details about an H-R diagram, but
should be able to read one and infer information from one.
Students are not required to know the Kelvin temperature scale.
On the Kelvin scale, absolute zero is the temperature where all
thermal motion will cease. The scale does not use the degree
designation. Absolute zero at 0 K = 273.15°C = 459.67°F.
Grade 8
Science
Unit: 11
Lesson: 02
Suggested Duration: 7 days
Last Updated 06/03/13 page 7 of 32
How is the H-R diagram a model? The H-R diagram models the different types
of stars and predicts star evolution, or aging, through its life cycle.
What are some limitations of the model? It’s a snapshot of the state of a
large collection of stars, it doesn’t show every star, and it can become verycrowded as more stars are added, especially in the main sequence area.
7. Ask students to reflect on the following questions in their notebooks. Allow them to
work with a partner.
Ask:
What characteristics are used to classify stars? Luminosity (brightness)
and/or absolute magnitude and temperature
How are stars classified on an H-R diagram? The stars are plotted according
to their magnitude and/or luminosity and temperature. They fall into categories of
main sequence, red giants, super giants, and white dwarfs.
Once a star has been identified as a main sequence star, will it always
remain in that area on an H-R diagram? No, it is a snapshot of the current
stage of a collection of stars. Its cycle will continue as its mass and temperature
change and it is no longer burning hydrogen in its core.
What factor determines the life cycle a star will have? (Mass)
How is the life cycle of a main sequence star different than that of a
massive star? A main sequence or small/medium star will become a red giant,
planetary nebula, white dwarf and then black dwarf. A massive star will become
supergiant, supernova, and then a neutron or black hole.
How is our Sun classified as a star? Our Sun is a medium, main sequence
star.
What star is closest to Earth? (Sun)
8. If time allows, show an approved animated version of how a star's brightness and
surface temperature are measured throughout its life cycle (see Advance
Preparation).
Science Notebooks:
Students answer reflective questions in their notebooks.
EVALUATE – Performance Indicator Suggested Day 6
Grade 08 Science Unit 11 PI 02
Create a field guide for stars, including our Sun, a supergiant, a giant, a main sequence star, and a
dwarf star. Provide a description, relative age and life span, luminosity, and temperature of each
star. Finally, describe how models such as a Hertsprung-Russel diagram can be used for
classification.
Standard(s): 8.2E , 8.8A , 8.8B
ELPS ELPS.c.1C , ELPS.c.2C , ELPS.c.5B
1. Refer to the Teacher Resource: Performance Indicator Instructions KEY for
information on administering the performance assessment.
Materials
paper (plain, multiple sheets per class)
paper (various per class)
colored pencils (per class)
Attachments:
Teacher Resource: Performance Indicator
Instructions KEY (1 for projection)
Grade 8
Science
Unit: 11
Lesson: 02
Suggested Duration: 7 days
Last Updated 06/03/13 page 8 of 32
Grade 8
Science Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 1
Galaxies and Stars Cards
white dwarf planetary nebula stellar nebula
protostars red giant elliptical
galaxies spiral black dwarf
neutron black hole irregular
Universe red supergiant main sequence
(small/medium) (Sun)
massive supernova
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 1
Galaxies
Irregular
Spiral
Elliptical
Picture
Description
How old are the stars?
How big is the average
galaxy?
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 1
Galaxies KEY
http://commons.wikimedia.org/wiki/File:I_Zwicky_18a.jpg
http://commons.wikimedia.org/wiki/File:I_Zwicky_18a.jpg
http://commons.wikimedia.org/wiki/File:I_Zwicky_18a.jpg
Irregular
Spiral
Elliptical
Picture
Description Undefined shape; no symmetry;
no bulge or disk
Contains stars; usually rich in
gas and dust
Held together by gravity
Disk shaped; resembles a
pinwheel with arms that spiral
outward
Contains stars; rich in gas and
dust
Held together by gravity
Round to flattened or elongated
spheres; bulge but no disk
Contains stars, a little cool gas,
and dust
Held together by gravity
How old are the stars? Young stars
Middle aged stars Old stars
How big is the average
galaxy?
Huge
Huge
Huge
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 1
Galaxies and Stars Questions
1. What are galaxies?
2. What are the types or categories for galaxies? 3. What is a nebula? 4. Where do stars begin their life? 5. What force helps a star begin to form?
6. What is the relationship between mass and the lifespan of a star? 7. What is the outcome of a star that runs out of hydrogen? 8. What kind of stars become white dwarfs?
9. What causes neutron stars to form? 10. What forms black holes? 11. What are the stages of a low/medium sized main sequence star? 12. What are the stages of a massive main sequence star? 13. What is the closest star to the Earth? 14. What size star is our Sun?
15. Where is our Sun located in the Milky Way galaxy?
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 1
Galaxies and Stars Questions KEY
1. What are galaxies? Galaxies are massive systems, bound by gravity, and consisting of stars and remnants of dead stars; galaxies are an interstellar medium of gas and dust.
2. What are the types or categories for galaxies? There are three major types of galaxies: spiral, irregular, and elliptical. Also, there is a quasar galaxy. 3. What is a nebula?
A nebula is a cloud of interstellar gas and dust from which stars form. 4. Where do stars begin their life?
Stars begin their life in a stellar nebula. 5. What force helps a star begin to form?
Gravity is the force that helps a star to begin to form. 6. What is the relationship between mass and the lifespan of a star?
Generally, stars with more mass have shorter life spans because they burn their fuel more quickly than smaller stars do. The mass also determines which direction the lifespan goes and ultimately, determines what the star becomes when it dies.
7. What is the outcome of a star that runs out of hydrogen?
The center of the star shrinks increasing the internal temperature. This extra heat and pressure allows helium to fuse, which causes the outer part of the star to expand forming a red giant or supergiant, depending on its original mass.
8. What kind of stars become white dwarfs?
Main sequence stars, specifically small and medium stars, become white dwarfs. 9. What causes neutron stars to form? After a high mass star becomes a red giant or super red giant, the gravity is so strong it causes the star to
contract again. This contraction causes new and different types of nuclear fusion to take place, which causes the star to explode into a supernova. If the left over remains are about three times the mass of the Sun or less, the remaining mass will contract back into a very small ball of neutrons. Neutron stars are so dense that a section the size of a grain of sand will have the mass of a large plane. *Note - This explanation is much more detailed than what is needed for a student, but has been done to provide teachers a detailed explanation of what is happening.
10. What forms black holes?
The remnants of the most massive stars that collapse upon themselves form black holes. 11. What are the stages of a low/medium sized main sequence star?
Nebula, protostar, star, red giant, white dwarf, and black dwarf are the stages of a main sequence star’s life. 12. What are the stages of a massive main sequence star?
Nebula, protostar, star, supergiant, supernova, and neutron star or black hole are the stages of a massive star’s life.
13. What is the closest star to the Earth?
Sun 14. What size star is our Sun?
Medium 15. Where is our Sun located in the Milky Way galaxy?
Our Sun is located at the edge of the galaxy.
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 1
Human Life Cycle Cards
Images courtesy of Microsoft clip art
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 3
Star Life Cycle Cards
Protostar Main Sequence Planetary Nebula Red Giant
White Dwarf Red Supergiant Super Nova
Neutron Star
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 2 of 3
Protostar Main Sequence Planetary Nebula Red Giant
White Dwarf Red Supergiant Super Nova Neutron Star
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 3 of 3
Protostar Main Sequence Planetary Nebula Red Giant
White Dwarf Red Supergiant Super Nova Neutron Star
Images courtesy of NASA.gov
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 1
Life Cycle of Stars Graphic Organizer
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 1
Life Cycle of Stars Graphic Organizer KEY
Grade 8
Science Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 1
Galaxies and Stars
protostars red giant stellar nebula elliptical galaxies spiral black dwarf main sequence (small/medium) supernova massive red supergiant irregular universe black hole planetary nebula white dwarf neutron
Grade 8
Science Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 1
Galaxies and Stars KEY
universe
galaxies
irregular elliptical spiral
stellar nebula
protostar
s
main sequence (protostars-small/medium)
massive
red giant red supergiant
planetary nebula
white dwarf
black dwarf
supernova
neutron black hole
protostars red giant stellar nebula elliptical galaxies spiral black dwarf main sequence (small/medium) supernova massive red supergiant irregular universe black hole planetary nebula white dwarf neutron
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 3
H-R Diagram Samples
http://commons.wikimedia.org/wiki/File:H-R_diagram.gif
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 2 of 3
http://upload.wikimedia.org/wikipedia/commons/d/db/H-R_diagram.svg
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 3 of 3
http://upload.wikimedia.org/wikipedia/commons/b/bb/H-r_diagram.svg
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 3
Stars From Afar
Purpose: Compare the temperature and brightness of various stars. Students will plot values on a
graph.
Materials:
pencil colored pencils ruler
Procedure:
1. Using the data from the Stars from Afar-Star Chart (pg. 2), plot stars on the H-R Diagram. 2. Make a pencil dot to represent stars on the Create an H-R Diagram (pg.3). 3. Plot the values of all the stars. Some of the values are not indicated on the H-R diagram;
therefore, you will have to use approximations when plotting these stars. 4. After all stars are labeled and graphed, use your colored pencils to shade in portions of the
graph. The colors of the graph will depend on the temperature range. Red: 2,000 K–3,500 K
Orange-Red: 3,500 K–5,000 K
Yellow-White: 5,000 K–7,500 K
Blue-White: 7,500 K–11,000 K
Blue: 11,000 K–30,000 K plus
Follow-Up Questions:
Due to the color appearance of stars, they are known as red giants or white dwarfs. Red giants tend
to be 100 times bigger than our Sun, but they are much cooler. On the other hand, white dwarfs are
roughly the same size as the Earth, yet they are much hotter than the Sun. Complete the following
steps using the following information
1. Find the four red giants, approximately 100 times the size of our Sun (Sun is 1.0 solar luminosity.),
in the red portion of the graph. Circle them, and label the group of stars “Red Giants”.
2. Find the three white dwarfs in the blue-white portion of the graph. They are the hottest and
dimmest stars. Circle them, and label the groups of stars “White Dwarfs”.
3. Find the four brightest stars, and circle them. Label the group of stars “Supergiants”.
4. The remaining stars that are located in an area from the upper left to the lower right are called the
main sequence stars. Circle and label them “Main Sequence”.
5. What happens to the temperature as you move to the right of the diagram?
6. What happens to the brightness as you move from top to bottom on your diagram?
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 2 of 3
Stars From Afar
Star Chart
Name of Star Surface
Temperature (K) Absolute Magnitude (M)
11 Ursae Minoris 4,340 - 0.4
Achenar 14,510 -2.8
Aldebaran 4,010 -0.6
Alpha Centuri 5,790 +5.4
Alpha Coronae Borealis A 9,700 +0.2
Alpha Coronae Borealis B 5,800 +5.1
Altair 7,700 +2.2
Antares 3,500 -5.3
Arcturus 4,300 -0.3
Barnard’s star 3,134 +13.2
Betelgeuse 3,200 -6.1
Deneb 8,525 -7.2
Pollux 4,865 +1.1
Procyon B 7,740 +13.04
Regulus 15,400 +11.6
Rigel 11,000 -6.7
Sirius A 9,940 +1.4
Sirius B 25,200 +11.2
Spica 22,400 -3.6
Sun 5,778 +4.8
Vega 9,620 +0.6
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 3 of 3
Stars From Afar
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 3
Stars From Afar KEY
Purpose: Compare the temperature and brightness of various stars. Students will plot values on a
graph.
Materials:
pencil colored pencils ruler
Procedure:
1. Using the data from the Stars from Afar-Star Chart (pg. 2), plot stars on the H-R Diagram. 2. Make a pencil dot to represent stars on the Create an H-R Diagram (pg.3). 3. Plot the values of all the stars. Some of the values are not indicated on the H-R diagram;
therefore, you will have to use approximations when plotting these stars. Because of the estimation involved in the placement of dots, individual graphs will vary. Assist students with finding the mid-point of each cell and estimating the values on each side of that point.
4. After all stars are labeled and graphed, use your colored pencils to shade in portions of the graph. The colors of the graph will depend on the temperature range. See the additional page 3 attachment for colors and labels KEY: Stars from Afar Lab Graph KEY. Red: 2,000 K–3,500 K Orange-Red: 3,500 K–5,000 K Yellow-White: 5,000 K–10,000 K (ending edge of yellow) Blue-White: 10,000 K–16,000 K (starting edge of blue) Blue: 16,000 K–30,000 K plus
Note: The temperature ranges are approximate. There is some blending of colors. See the
lesson.
Follow-Up Questions:
Due to the color appearance of stars, they are known as red giants or white dwarfs. Red giants tend
to be 100 times bigger than our Sun, but they are much cooler. On the other hand, white dwarfs are
roughly the same size as the Earth, yet they are much hotter than the Sun. Complete the following
steps using the following information
1. Find the four red giants, approximately 100 times the size of our Sun (Sun is 1.0 solar luminosity.),
in the red portion of the graph. Circle them, and label the group of stars “Red Giants”.
2. Find the three white dwarfs in the blue-white portion of the graph. They are the hottest and
dimmest stars. Circle them, and label the groups of stars “White Dwarfs”.
3. Find the four brightest stars, and circle them. Label the group of stars “Supergiants”.
4. The remaining stars that are located in an area from the upper left to the lower right are called the
main sequence stars. Circle and label them “Main Sequence”.
5. What happens to the temperature as you move to the right of the diagram? The stars get cooler.
6. What happens to the brightness as you move from top to bottom on your diagram? The stars get
dimmer.
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 2 of 3
Stars From Afar Lab Star Chart
Name of Star Surface
Temperature (K) Absolute Magnitude (M)
11 Ursae Minoris 4,340 - 0.4
Achenar 14,510 -2.8
Aldebaran 4,010 -0.6
Alpha Centuri 5,790 +5.4
Alpha Coronae Borealis A 9.700 +0.2
Alpha Coronae Borealis B 5,800 +5.1
Altair 7,700 +2.2
Antares 3,500 -5.3
Arcturus 4,300 -0.3
Barnard’s star 3,134 +13.2
Betelgeuse 3,200 -6.1
Deneb 8,525 -7.2
Pollux 4,865 +1.1
Procyon B 7740 +13.04
Regulus 15,400 +11.6
Rigel 11,000 -6.7
Sirius A 9,940 +1.4
Sirius B 25,200 +11.2
Spica 22,400 -3.6
Sun 5,778 +4.8
Vega 9,620 +0.6
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 3 of 3
Stars From Afar Lab
Grade 8 Science
Unit: 11 Lesson: 02
©2012, TESCCC 06/03/13 page 1 of 1
Stars From Afar Graph KEY
Grade 8 Science
Unit: 09 Lesson: 01
©2012, TESCCC 06/03/13 page 1 of 1
Performance Indicator Instructions KEY
Create a field guide for stars, including our Sun, a supergiant, a giant, a main sequence star, and a dwarf star. Provide a description, relative age and life span, luminosity, and temperature of each star. Finally, describe how models such as a Hertsprung-Russell diagram can be used for classification. (8.2E; 8.8A, 8.8B)
1C; 2C; 5B Materials:
paper (plain, multiple sheets per class) paper (various per class) colored pencils (per class)
Instructional Procedures:
1. For the field guide, students may choose to make a mini booklet or other type of book. They may use their notebooks for information, and you may want to allow the use of computers for the diagrams. They may also draw a representation of the star in color, rather than trying to download photos.
2. Inform students that the field guide should contain a separate page for each of the following ( a total of five pages): our Sun a supergiant a giant any main sequence star other than our Sun a white dwarf
3. Include the following for each star:
luminosity and/or absolute magnitude labeled as such temperature a description of each (color and other descriptive information as appropriate) relative age and life-span (This can be summarized such as a “young star”, nearing the end of
its life span”, or “about half through its life”.)
Performance Indicator