MGS-111 Lab 4 Grating Spectrometer Objectives: To observe spectra of different light sources using a diffraction grating and camera, and to calibrate the wavelength axis of the spectra. To understand how different sources that appear white to humans may actually have very different spectra. To gain experience in how scientists observe the light spectra of objects, whether emitted or reflected. Materials used in the experiment: 1. A transmission diffraction grating attached to a tube with slit at the opposite end. 2. A camera, in iPhone in this case and images of a tungsten bulb, a fluorescent lamp, an LED lamp, and a red and green laser spot. 2. Fiji (or Image J) software (or other image processing software). Background: You are probably familiar with how a prism can spread sunlight into the spectrum of colors. However, for scientific instruments it is more common to use a diffraction grating to spread the spectrum by leveraging the wave properties of light (Huygen's Principle). Diffraction gratings are used especially for optical measurements of ultraviolet, visible, and near infrared spectral radiation. The deviation angle, , of a diffraction grating has a linear dependence on the wavelength of the light, as shown in Eqn 1