The Electromagnetic Spectrum
Visible light from the Sun is actually composed of the colors red, orange, yellow, green, blue, indigo, and violet, which can become distinguishable when sunlight passes through a prism. A good way to remember the order of the colors is to note that the first letters of the colors spell out the name ROY G. BIV. We can think of light traveling in waves with properties of wavelength and frequency. Wavelength is the distance between identical locations on adjacent waves.
Frequency is the number of complete waves, or wavelengths, that pass a given point each second. All light travels at the same speed, but each color has a different wavelength and frequency. It is their different wavelengths that cause the different colors of light to separate and become visible when passing through a prism.
True wavelengths are actually measured in terms of angstroms. An angstrom is 10^-8 cm or 0.00000001 cm. For our purposes, we'll measure wavelengths in meters or nanometers. Frequency is measured in cycles per second, which is called a Hertz.
Journal Entry # 2
Using the graphic on the electromagnetic spectrum shown to the left, think about the relationships among the various wavelengths and the position of each type of radiation in the electromagnetic spectrum. Write a summary explaining what the electromagnetic spectrum is and how it is measured.