Essential Questions: What is the universe made of? How do we know? How does the universe change over time?
In this series of activities you will investigate the process of nuclear fusion related to Einstein's famous equation E =
MC 2 and learn how mass, in the form of hydrogen atoms, is converted to helium and causes a release of energy that makes stars shine! Cool!! Or hot?
You will also understand the forces involved in stars that maintain this nuclear reaction and how these forces change as the star ages.
You will explore the stages stars progress through from birth to death and how the death of a star depends on its initial mass.
You
will also build and interpret Hertzsprung-
Russell diagrams and learn how they can be used to classify the life cycle stage of a star by its luminosity, temperature, magnitude, and spectral class.
Finally, we will go deeper into space and will discover how infrared, xray, and gamma ray telescopes are being used to detect the life cycle stages of stars. This is an independent learning module so do your best to understand what you are learning or doing. Ask questions to clarify! The summative assessment is at the end. Don’t forget to click on the hyperlinks! Good luck in your adventures!
Task #1: You will begin your Webquest by learning how to identify stars by their magnitude, color, temperature, and spectral class.
Click Stars: Lights in the Sky and write out the questions and answers to the following on a sheet of white construction paper to be turned in. Be sure your name and period are on it.
1) What is the name of the brightest star in our night sky? What is the name of the brightest star in all of the known universe?
2) - What is the absolute magnitude of the two stars in question 1?
3) - What is the difference between apparent and absolute 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?
6) - Do a search on the Internet for "brightest stars" and make an illustrated top 10 list on your construction paper of the names and colors of the 10 brightest stars in the known universe and their absolute magnitude.
7) - Finally, design a creatively colored diagram on your paper that displays the colors of the hottest stars on the left to the coolest stars on the right using colored pencils. 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 paper. Memorize it! Be sure to know it when you turn your paper in as you will be asked about the spectral class!
Answer the following few more questions and write the answers on your paper.
8) - What color is the brightest star?
9) - What color is the coolest star?
10) -What color is our sun?
11) -What spectral class of stars is the hottest?

12) -What spectral class of stars is the coolest?
13) - 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 different forms of hydrogen (deuterium and tritium) to form helium. Your task is to design a 3-D model of this nuclear reaction. You might want to use some pom-pom balls or other round objects supplied by the teacher to represent the different atoms in the reaction. You need two different colors. Glue these on an 5x7 index card and label the names of the atoms, particles and processes and use arrows to show the progression of the reaction. Be colorful and creative! Make sure you understand what is happening and why. Show your teacher and be prepared to answer questions.
Task #3: Go to The Life and Death of Stars . Build quality illustrated notes in your journal. 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? Why would it do this? What forces
(interactions) are happening to cause this?
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 the Hubble Space Telescope and then explore the site looking for Image Tour of a star called V838 Monocerotis. Why did it die this way? Why do the stars have 4 points in Hubble Photographs?
Cool! No, hot! How does mass effect the stars life cycle? Be prepared to share your understandings and the answer to this question with your teacher.