Prof. McElroy took this picture using the little diffraction grating we passed out in class - if you have taken an interesting or fun picture with yours, send it to us and we'll post it in the virtual office hours!
Gratings spread the colors (wavelengths) of light out to different angles, showing the spectrum of the light. Every element has a distinctive spectral pattern of natural emission lines (colors), and thus gratings ("spectroscopy") allow us to figure out what elements are present -e.g. in chemical or biological samples (even in tiny concentrations), or in distant stars! It always strikes me as remarkable how much we can learn about stars, just by looking at little points of light - it is through the wavelike properties of light that we can do that!
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This website will be up for as long as CU maintains websites. My personal belief is that I am your physics teacher for life, not just for one semester! When you have fresh questions about physics some day, feel free to email or visit. Prof. McElroy and I hope you view this class as opening a door to continuing to learn more about the physical world you live in - SJP

• Course grades are now up on D2L, and posted to the CU system.
• Have a great break, keep on learning!
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  Earlier homepage and announcements can be found here:
  week #1, week #2/3 , week 4 , weeks 5/6, week 7, week 8, week 9, week 10, week 11, week 12, week 13