20.2 - Optical devices

Light travels in straight lines in a vacuum but light rays may bounce (reflect) or bend (refract) upon interacting with matter. Many technologies and objects exhibit the reflection and/or refraction of light, including eyeglasses and contact lenses, mirrors in dressing rooms, rear-view mirrors on cars, a glass of water, and even the cut and polished diamond in a ring. The science and technology of manipulating light is the field of optics. Read the text aloud
Examples of optical devices
Optical devices
A mirror is a basic optical device that diverts light using reflection. Most large mirrors are flat, such as the mirror above the sink in a bathroom. Mirrors can also have curved surfaces, which create unusual reflections—especially the wavy mirrors found in a funhouse that make you look skinny or short! Most mirrors are made from clear glass with a thin layer of aluminum or silver sprayed on the back side to reflect light. Many metals can also be polished smooth and shiny to act as a mirror. Read the text aloud Show Silvering
A camera is an example of a device that uses lensesA lens has a curved surface that bends light by refraction. Lenses are found in many optical technologies including magnifying glasses, microscopes, and all types of cameras including video cameras and the camera on the back of a mobile phone. Lenses are usually made from transparent polished glass or plastic. Read the text aloud
A prism is an optical device with flat surfaces that uses refraction to divert the path of light. Because different colors of light refract at slightly different angles, a prism may disperse white light into its constituent colors. Dispersion explains how a triangular prism separates a beam of white light into the colors of the rainbow. Prisms in technology are made from transparent polished glass or plastic. In nature, droplets of water act as tiny prisms to create rainbows. Read the text aloud

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