Building a Fancy Spectrograph
A university student operates a slit-less CCD spectrograph, used during NASA's Lenoid MAC mission to space.Copyright NASA http://leonid.arc.nasa.gov/01image_archive.html
Students create and decorate their own spectrographs using simple materials and holographic diffraction gratings. A holographic diffraction grating acts like a prism, showing the visual components of light. After building the spectrographs, students observe the spectra of different light sources as homework.
Spectrographs are used both in ground-based telescopes and in space to help astronomers answer questions about what makes up atmospheres of planets and stars. Mechanical and electrical engineers design spectrographs to advance our knowledge of astronomy. Simple spectrographs, like the one the students build, are similar to the first spectrographs astronomers used in the past.
After this activity, students should be able to:
- Explain that light seen through a diffraction grating shows all of the colors of that light.
- Explain why lights that are the same look the same through the diffraction grating.
- Explain that patterns can tell us something about what kind of light we see.