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Color and Light · entry 37 of 52
The color of a flame changes with temperature, shifting from red toward blue as it gets hotter.
The longer version
Hot objects radiate more strongly at shorter wavelengths as they get hotter, so a flame's glow climbs from dull red through orange and yellow toward white and blue. Soot particles glowing in the fire produce most of the yellow, while excited molecules emit the blue.
Chemists use the principle to judge burners and furnaces, and astronomers apply the same relation to stars, reading surface temperature from colour. A candle flame shows the gradient in a few centimetres, with a blue base and a yellow tip. Adding certain metals to a fire produces vivid colours from their own emission lines.
Where this entry sits
These facts explore how light behaves and how human eyes turn it into the colors we see. Along the way you meet rainbows, prisms, mirrors, shadows, lasers, and optical tricks that fool our vision every day. The full list sits on the Color and Light page, where every entry is listed in order.
More From Color and Light
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Read 39Afterimages appear when staring at a bright color fatigues the cone cells responding to that hue.
Read 40A gray square looks lighter on a black background than the same square on a white one.
Read 41Neon colors seem to glow because they reflect more light than ordinary dyes can.
Read 42Fluorescent materials absorb invisible ultraviolet light and re-emit it as visible color.
Read 43Glow-in-the-dark objects store light energy and release it slowly over several minutes.
Read 44Polarized sunglasses reduce glare by blocking light waves vibrating in one particular direction.
Read 45Soap bubbles show shifting colors because thin films interfere with reflected light waves.
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