Life Cycle of Stars

The Life Cycle of Stars

Grade level(s) 9-12


Created by: Steve Cogan
Capistrano Unified School District 


Task #1

1) You will begin your webquest by learning how to identify stars by their magnitude, color, and temperature, and spectral class. 

Click Stars: Lights in The Sky and write out the answers to the following questions on a sheet of white construction paper to be turned in.

2) - Name the brightest star in the known universe.

3) - What is its magnitude? 

4) - Are the brightest stars low magnitude or high? 

5) - How much does the brightness of a star change with each change in magnitude of one? 

Do a search on the internet for "brightest stars" and make a top 10 list on your construction paper of the names of the 10 brightest stars in the known universe and their magnitude. 

6) - Finally, design a colored diagram on your construction paper that displays the colors of the hottest stars on the left to the coolest stars on the right.
Stars are grouped into spectral classes based on a range of temperatures they fall into.
Label the spectral classes (O, B, A, F, G, K, M)
appropriately under each star color in your diagram. 

To complete Task #1, 

come up with a clever sentence or phrase (the first letter of each word in your phrase is one spectral class letter) to help you remember the order of the spectral classes and write it under your diagram on your construction paper. 

Answer the following few more questions and write on your construction paper.

7) - What color is the brightest star? 

8) - What color is the coolest star? 

9) -What color is our sun? 

10) -What spectral class of stars is the hottest? 

11) -What spectral class of stars is the coolest? 

12) - What spectral class is our sun?

Task #2:  Continue to read on to the section: A Nuclear Furnace on the same webpage. The animation there shows how stars fuse the deuterium and tritium forms of hydrogen to form helium.  Your task is to design a 3-D model of this nuclear reaction. You might want to locate some red and blue styrofoam balls at an art supply store or utilize some type of spherical object to represent the different atoms in the reaction. Glue these on a piece of cardboard and label the names of the atoms and draw arrows showing the progression of the reaction.  

Task #3: Goto The Life and Death of Stars.  Read the short section on "Where are stars born" and see pictures of the protostars of M16: The Eagle Nebula and other nebulae (stars in formation) on this page.  Continue by reading up on Main Sequence Stars and find out how our sun compares in mass to other stars like Sirius, and Proxima Centauri. Based on its mass, will our sun be around for a while? approximately how long before our sun consumes the inner planets of our solar system.

 Realize that once our Sun starts to run out of hydrogen fuel and has exhausted its ability to fuse other elements like carbon and oxygen, it will become a red giant and expand in size to envelope the Earth. And surprisingly, the larger the mass of the star, the quicker it burns its fuel sources and the shorter its lifespan. Also see and read about Hubble Space Telescope pictures of a developing galactic nebula in our Milky Way Galaxy called NGC 3603 

Task #4: Being that stars are quite more massive than most planet sized objects, the gravitational pull on objects close to stars is astronomically large. Find out Your Weight On Other Worlds like different types of stars and even planets. 

Task #5: Now check out the All Star Line Up and profile one of the 34 stars on this page. Organize the info provided about your chosen or assigned star into a one page report, a poster, or maybe a short Powerpoint slide show (get extra credit if you design a slide show)

Task #6:
The life cycle of stars continues.......All stars eventually become Red Giants or Super Giants.
As the main sequence star glows, hydrogen in its core is converted into helium by nuclear fusion. 

When the hydrogen supply in the core begins to run out, and the star is no longer generating heat by nuclear fusion, the core becomes unstable and contracts. The outer shell of the star, which is still mostly hydrogen, starts to expand. As it expands, it cools and glows red.
The star has now reached the red giant phase.

It is red because it is cooler than it was in the main sequence star stage and it is a giant because the outer shell has expanded outward.

In the core of the red giant, helium fuses into carbon.  All stars evolve the same way up to the red giant phase. 

The amount of mass a star has determines which life cycle path it will take ...........Read more about Red Giants.

Task #7:  See animation of a Supernova explosion and photographs of actual supernova detected by emitted X-rays. At this point, stars at least 5X more massive than our Sun that have gone supernova will either die as a neutron star or a black hole. 

Make a poster display of the Life Cycle of Massive Stars on a small poster board. Label and color the star types and progression correctly for full credit. 

One neat idea you might want to try is to use crayon to design this life cycle diagram on your white poster board and then color over all of it in black crayon. If you can remember where objects in your diagram are, etch off the black crayon with a penny or other object to expose the diagram in color underneath. 

Task #8:  Time for some fun as a reward. Play the Falling Stars Applet Game and destroy those falling stars.  Email me the game webpage with the score you earned on it.   Highest score gets a reward before Winter Break.

Task #9:  Go to The Space Place and play the Black Hole Board game. Get a group together, print out the color game board and adventure cards, bring the game to school, and have all members of your gaming group see me for extra credit.

Task #10Here's a chance to model your own black hole. 

Go to Nasa's Life Cycle of Stars Curriculum packet.   Go to the activity Model a Black Hole and follow all directions there. Bring in your model to share for extra credit points. You may also do any of the other activities there for extra credit. See me about activities or projects you plan to do. 

Task #11:  Finally, go take the interactive five-question quiz below and see how much you have mastered about the Life Cycles of Stars.


Now you are ready for 

A Few Internet Resources:

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Created August 22, 2003
Last Revised September 11, 2003

Teacher Notes

Suggested Grade Level: 6 to 9 ?? 

California Content Standards: - Note these are only examples. Use the links below to find the standards for your WebQuest.

Grade 6: Investigation and Experimentation (7a, b, c, e, g, h)
Grade 7: Investigation and Experimentation (7a, b, c, e)
Grade 8: Investigation and Experimentation (9a, b, e)
Grade 9: Investigation and Experimentation (1a, c, d, i) 

   Science-Grade 9 Grade 10 Grade 11 Grade 12-Earth Sciences

   2c Evidence that all elements with an atomic number greater than that of Lithium have been formed by nuclear fusion in stars.

   Science-Grade 9 Grade 10 Grade 11 Grade 12-Earth Sciences

   2d Stars differ in their life cycles, and visual, radio, and X-ray telescopes collect data that reveal these differences.

Search the standards:

S.C.O.R.E. Lessons Standards Search by Grade and Subject
S.C.O.R.E. Standards and Framework
California Content Standards Grades K-12
California Content Standards Grades K-12 - Science - PDF Format 


Students should have a basic understanding of the physical properties of matter such as phase changes and temperature.
Prior to this webquest, students should be oriented with the types of light of the electromagnetic spectrum and the structural layers of the Sun. 

Computer literacy.
Interpreting data, making inferences, forming hypotheses, making predictions, graphing.
Effective use of Internet resources including searching and being able to recognize credible websites for sources of information.

Poster projects, presentations, modeling, puzzle designing, worksheets, peer evaluation, rubric, interactive quizzes and Internet activities.

Presentations - PowerPoint or Hyperstudio, student created web page, web based activites.
See the Life Cycles of Stars NASA curriculum packet below for an assortment of ideas for enrichment
For some advanced interactives especially one on the H-R Diagram go to the Online Learning Center

For advanced understanding of how stars are classified see - H-R Digaram page
Students can view a virtual telescope site to create wonderful teslescopic images.
Check out the Earth and Moon Viewer page and Interactive Earth viewer from space

For example, Density Lab - Requires a free user name and password:  UN = littleone  PW = toronto

List of Website References/Resources:

Sheppard's Science Resources / U.C.I. SSI
The Evolutionary Cycle of Stars
WMAP Cosmology 101: Life Cycle of Stars
CNN - New Hubble image shows life cycle of stars - June 1, 1999
X-ray Astronomy: Supernovae and their remnants - Introduction
Sea and Sky: Stars
Background: Life Cycles of Stars
Scientific Background for Life Cycle of Stars - Lesson Plan: Supernova Chandra - April 26, 2000
Explorations: Stars, Galaxies, and Planets | Interactives
Life Cycles of Stars NASA Curriculum Packet