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If you have ever been out in the intense sun too long and received a sunburn, you know how powerful the sun's light energy can be. Sunlight is a form of energy, referred to as radiation. It travels in waves. The distance between the top or crest of one wave and the crest of the next wave is a wavelength of light. Sunlight, also called white light, is a mixture of all visible wavelengths, as well as many wavelengths we can't see. When white light passes through a prism, it's bent by different amounts, spreading out the light into a spectrum we see as different colors. The colors appear in order of their wavelengths, with the shortest wavelength, violet, at one end, and red, the longest wavelength, at the other end of the spectrum. While light behaves as waves, it also acts as if it were made up of energy particles called photons. The shorter the wavelength of light, the more energy a photon carries. Certain substances, called pigments, are capable of absorbing photons and their energy. Specific types of pigments absorb certain wavelengths of light and reflect others. The different wavelengths of light absorbed by a particular pigment make up its absorption spectrum. Two general types of pigments, chlorophylls and carotenoids, are found in green plants. The pigments chlorophyll a and chlorophyll b absorb violet blue and red light. Carotenoids absorb light primarily in the violet, blue range. You decide. Why do plants look green?
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Chlorophylls and carotenoids do not absorb light in the green part of the spectrum. Instead, they reflect green light. Consequently, most plants appear green.