light
Post on 12-Sep-2014
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LIGHT
Objectives:The student will investigate and understand basic characteristics of white light. Key concepts include:
• The visible spectrum, light waves, reflection, refraction, diffraction, opaque, transparent, translucent;• Optical tools (eyeglasses, lenses, flashlight, camera, kaleidoscope, binoculars, microscope light boxes, telescope, prism, spectroscope, mirrors); and• Historical contributions in light
Explain the relationships between wavelength and the color of light. Name the colors of the visible spectrum.
Vocabulary:• Waves: a disturbance which carries energy and
that travels away from the starting point.• Wavelength: the distance between one crest of a
wave and the next crest (distance between compressions); red is longest and violet is shortest
• Peak: the highest point of a light wave• Trough: the lowest point of a light wave• Frequency: the number of waves (light or sound)
produced in a given unit of time, such as a second
• Visible spectrum (visible light): a combination of several different wavelengths of light traveling together. It is part of the Electromagnetic Spectrum.
• Reflection: the bouncing of light from a surface• Refraction: the bending of light as it passes through one material to another
Diagram Representation of Light Wave
Reflection Refraction
A convex lens causes light to converge, or focus,producing an image that is smaller than the original object.
Two kinds of Lens
A concave lens causes light to diverge, or spread out,producing a larger image than the original.
Optical Tools that has lenses, mirrors and/or prisms in it:
• eyeglasses• flashlights • cameras • binoculars• microscopes
Eyeglasses: have lenses
Flashlight: has lenses and a mirror
Cameras: have lenses, mirrors, and a prism
Binoculars: have lenses and prisms
Microscope: has lenses
Plastic wrap Wax paper Aluminum Foil
Transparent Translucent Opaque
Three kinds of Materials:
Transparent: materials that allow all light to pass through Translucent: letting light through but scattering it Opaque: materials that do not let light throughTransmit: to send (as in sound or light). It also means light passing through an object
Scientist with contributions in using and creating optical tools:
Galileo Galilei
• Italian• Lived from 1564-1642• Developed the refracting telescope• Developed the first known example of the
microscope
Robert Hooke
• English• Lived from 1635-1703• Devised the compound microscope and
illumination system• Discovered plant cells• Examined fossils with a microscope
Anton van Leeuwenhoek
• Dutch; born in Holland• Lived 1632-1723• Made over 500 simple microscopes• Discovered bacteria, free-living and
parasitic microscopic protists
Isaac Newton
• English• Lived from 1643-1727• Discovered that white light was not a
simple entity, but splits into a range of colors
• When he passed white light through a glass prism, he noted that a spectrum of light was formed; particle theory of light
• Reflecting telescope