Color
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 the thermal
radiation given off by hot objects, 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 any 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
Project Goals
By the end of the project, students should be able to:
- Recognize the rich variety of
colors in the night sky
- Ask scientific questions about
everyday phenomena
- Know that light is a wave, and
explain the relationship between wavelength and observed color
- Know the order of the visible
spectrum, from red to violet, and the total electromagnetic spectrum, from radio waves
to gamma rays
- Explain how telescope filters are
used in astronomy
- Explain how the color of stars
stars is related to the peak wavelength of light they emit
- Explain why red, orange, yellow,
and blue stars are common, while stars with other colors from the
visible spectrum are rare
- Look up data using several
interfaces
- Compare the astronomical
definition of color to the color they see with their eyes
- Understand that hot objects give
off more thermal radiation than cool objects
- Explain how the peak wavelength
of thermal radiation changes as objects heat up
- Explain why the color of a star
can not be found from its temperature alone
- Find peak wavelengths of observed
stellar spectra
- Qualitatively understand how to
find astronomical colors from a thermal radiation curve
- Make simple x-y graphs
- Identify cool and hot stars on
different color-color diagrams
- Use data to judge when a
scientific analysis is appropriate
- Prepare, execute, and interpret
an independent scientific research project
Background Knowledge
Before beginning this project, students should:
- know that stars come in different
colors
- know that light is composed of
waves with definite wavelengths
- know what stars, galaxies, and
the universe are
- know that hot objects glow, and
that heat and light are related
- have some experience with
scientific reasoning
- have mathematics experience up to
and including Algebra I
- know how to look up information
using a web-based interface such as a search engine
- have some familiarity with a
spreadsheet program such as Microsoft Excel
Project Structure
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 four chapters:
Chapter 1: Introduction and Exploration |
1 hour |
Chapter 2: Definition of Color in Astronomy |
2 hours |
Chapter 3: Thermal Radiation, Temperature, and
Observed Spectra |
3 hours |
Chapter 4: Color-Color Diagrams |
4 hours |
Chapter 5: Conclusion/Research Challenge |
1 hour |
The Research Challenge, on the Conclusion 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 the Research Challenge 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 the 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
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