This interactive is used in Chapter 16.
Astronomy can be defined as the study of light that reaches us from the heavens. That light carries vast stores of information, if you know how to read it. The spectra of stars give clear, unambiguous clues to their temperatures and atmospheric compositions, among other things. This Interactive shows you how it works: that stars of different temperatures have unique blackbody spectra, and that absorption lines within those spectra disclose the atmospheric elements of the star. Choose the temperature of a star, select some elements for the atmosphere, and the correct spectrum appears.
Source
http://highered.mheducation.com/sites/007299181x/student_view0/interactives.html#