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This project shows students the brilliant colors of stars, then teaches them why stars come in so many colors. Answering this question takes them through the definition of color in astronomy, the nature of thermal (blackbody) radiation, and the use of colored telescope filters.
For more information on how astronomers use color, and on the physical meaning of color, read the About Astronomy: Stars section of SkyServer, or look in an astronomy or physics textbook. Here are a few possible references:
Halliday, David, Jearl Walker, and Robert Resnick, Fundamentals of Physics, John Wiley and Sons, 2000
Hartmann, William K., Astronomy: the Cosmic Journey, Wadsworth, 1989
Kaler, James, Extreme Stars, Cambridge University Press, 2001
By the end of the project, students should be able to:
Before beginning this project, students should:
The section "Color and Amounts of Light," including Exercises 2-4, requires that students multiply and divide using logarithms. If your students are not comfortable using logarithms, you may skip this section.
They should also have basic computer skills. They should know how to look up information using a Web-based interface. It is helpful to know how to use Microsoft Excel or some other graphing program, but not necessary.
The Color project is a long-term project, designed to take about 11 hours to complete. You may wish to assign some parts as homework. The project can be divided into five chapters:
Chapter 1 begins with the Introduction and ends with the Colors of Stars in the SDSS.
If you would like to use a shorter version of the project with your class, you may stop after one of the chapters. For example, if you want your students to learn how astronomers define color, without learning the cause of stellar color, you may stop after Chapter 2.
If your students are not comfortable using logarithms, you may skip the "Color and Amounts of Light" section in Chapter 2. The shorter Chapter 2 should take about 1 hour.
The Research Challenge, on the Colors in Astronomy Research page, should not be done in the classroom for credit. It is designed to be a completely open-ended and independent scientific investigation, and it should take many hours to complete. You may wish to give extra credit for completing it. Invite students to discuss their research questions and approaches with you. When students finish Exercise 13 on their own, encourage them to E-mail their results to us. We will look at all the results we receive, and we will put them best of them up on the project web site.
Questions and Exercises
Questions are designed to get students thinking about the reasoning scientists use in their work. Exercises come in two types: Practice and Explore. Practice exercises let students practice using the concepts introduced in the project. Explore exercises are designed to get students to explore SkyServer data to discover concepts on their own. For answers to all Questions and Practice exercises, and sample responses to all Explore exercises, click here. To see the answers, you must have the Adobe Acrobat PDF viewer installed on your computer. Acrobat is available for free download at Adobe's web site.
Students should be evaluated based on their written answers to the questions and exercises. You may use our sample scoring rubric or develop your own. If you use our scoring rubric, print out a copy for each student and attach it when you return his or her work.
For specific information on any part of the project, click Next.