Humanized Physics Project
How Do We See Colors?
Light and Optics - Module LO
LO1: From Where Does Light Come?
Big Idea
Introduce the contemporary concept of light as consisting of photons which arise from the
transition of atoms from higher energy states to lower energy states.
Physics Objectives
 Recall the properties of waves and the equation, f  = c
 Develop the source-medium-detector model for light
 Examine light sources and develops two categories: continuous spectra and line spectra
 Demonstrate the photoelectric effect
 Invent the Planck equation, E = h f
 Introduce the electron volt as a unit of energy
 Realize that different frequencies (colors) of light behave differently in prisms, or gratings,
and in detectors
Human Applications Objectives
 Realize that colors are words for different wavelengths, or frequencies, of light and be able
to link the main colors to their wavelength, or frequency, regions.
 Realize the visible part of the total E&M spectrum is quite small.
 Realize the energy of visible photons is about 2-4 eV, much larger than thermal energies,
i.e. room temperature energy is about (1/40) eV.
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