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Light and Color for the Middle School. By Greg Corder. TOC. Reflection and mirrors Refraction and lenses Applications of lenses and mirrors Color: light, pigments, and wavelength Diffraction Interference Light the electromagnetic wave Photoelectric effect
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Light and Color for the Middle School By Greg Corder
TOC • Reflection and mirrors • Refraction and lenses • Applications of lenses and mirrors • Color: light, pigments, and wavelength • Diffraction • Interference • Light the electromagnetic wave • Photoelectric effect • Nature of light: particle, wave, or both?
Curved Mirrors • Concave mirrors converge light. • Convex mirrors diverge light.
Concave Mirror Light converges. This means that it comes together. Also, the image is flipped past the focal point.
Convex Mirrors Light diverges. This means that light spreads out.
Curved Lenses • Convex lenses converge light. The image is flipped past the focal point. • Concave lenses diverge light.
Refractions causes light to bend. The shape of the lens determines how the light behaves.
Dispersion… Color separates using a prism because different colors have different wavelengths. Red light bends the least and purple light bends the most.
Colored lights add to become white. Why then do paints add to become black?
Answer: paints are pigments. Pigments are chemicals which are capable of absorbing one or more frequency of white light.
Diffraction – a wave bends around an object Light is a wave!
The Electromagnetic Spectrum • Maxwell - (c. 1864) light is an EM wave
The photoelectric effect: light is a particle! The puzzle of intensity vs. energy
Einstein - (1905) • The duality theory of light • Light has a dual nature: light is both a particle and wave
Sources:http://www.glenbrook.k12.il.us/gbssci/phys/Class/BBoard.htmlhttp://www.mhhe.com/tilleryTillery, Physical Science.http://cougar.slvhs.slv.k12.ca.us/~pboomer/physicslectures/secondsemester/telescopes/refracting.jpg