ARSC/GEOL 2110
Physical Science of the Earth System
What is in a Star & The Colors of Stars?
Fall 2001

Study Exploration 2C in "What is in a Star?" Due Tuesday October 9th.

Read "Creating the Context" and use the Quicktime movies on the web site (http://chemistry.beloit.edu) or CD (not the URL in the module) to work your way through the questions #1-8. Ch. 3 in Blue Planet, especially "The solar spectrum" pp. 52-53, will be a useful resource. Bring your answers (and your questions) to class for discussion on Tuesday.

Lab Report on the Color of Stars. Due Thursday, October 11th.

Answer the following questions from "What is in a Star?"

Part I.

Answer the following questions from Exploration 2B:

#14, p. 20 (sketches need to show source and color of light at each stage, object, observer. Be specific about color!)
#16, p. 20
#17, p. 20
#18, p. 20

Part II.

Use the blackbody radiation movies in Exploration 2C and the star spectra in your packet to answer the following questions. You will have three stars of your own to analyze, but not the same three as anyone else. You will use this information for your final stars project, so be sure you keep a copy of it for your own records as well as the copy you turn in. These questions are based on our work on last Thursday but will likely go more easily for you after you have completed the assignment above for next week. Review the 'hot objects' movies from Exploration 2A if you need to.

a) Using what you know about how the blackbody spectrum changes with temperature, rank your stars in order from coolest to hottest.
b) By comparing with the blackbody movies and judging lambda-max. (wavelength of maximum intensity) and shape of the blackbody curve as best as you can, estimate the colors and temperatures of each.
c) Explain how it is possible to determine the color and temperature of a star by comparing it with a blackbody spectrum.
d) How well does the model of a blackbody work for a star? List a few features that it does and does not model well.