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electromagnetic wave An energy-carrying wave emitted by a vibrating charge (often electrons) that is composed of oscillating electric and magnetic fields that regenerate one another.
electromagnetic spectrum The range of electromagnetic waves extending in frequency from radio waves to gamma rays.
transparent the term applied to materials through which light can pass in straight lines
opaque the term applied to materials that absorb light without reemissio nand thrus through which light cannot pass.
shadow a shaded region that appears where light rays are blocked by an object.
umbra the darker part of a shadow where all the light is blocked
penumbra a partial shadow that appears where some but not all of the light is blocked
solar eclipse an event wherein the Moon blocks light from the Sun and the Moon's shadow falls on part of the Earth
lundar eclipse an event wherein the Moon passes into the shadow of the Earth
ultraviolet light EM waves with a frequency just higher than visible light, causes cancer with prolonged exposure.
infrared light EM waves with a frequency just lower than visible light, responsible for the "warmth" we feel from sunlight.
cornea transparent cover over the eye
pupil the opening created by the iris through which light enters the eye
iris the colored part of the eye that increases or decreases the size of the pupil
retina speciallized tissue made of rods and cones that covers the back of the eye
fovea center region of the retina where vision is most distinct
blind spot the location on the retina where the optic nerve exits toward the brain
optic nerve located behind the retina, it transmits signals from the photoreceptor cells to the brain
additive primary colors the three colors - red, blue, and green - that, when added in certain proportions, produce any other color in the visible light part of the EM spectrum and can be mixed equally to produce white light
complementary colors any two colors that, when added, produce white light
subtractive primary colors the three colors of absorbing pigments - magenta, yellow, and cyan - that, when mixed in certain proportions, reflect any other color in the visible light part of the EM spectrum.
pigments fine particles that selectively absorb light of certain frequencies and selectively transmit others
radiation curve of sunlight a graph of brightness versus frequency that shows sunlight is brightest in the yellow-green region, in the middle of the visible spectrum
atmosphereic ducting the refraction (bending) of light as it passes through the Earth's atmosphere
Created by: lpgullett