The "Tell Me a Trivia Or Two About Yourself" Threa

Calan · **Posted:** Tue Sep 09, 2008 2:46 pm

Quote:

(You're getting it wrong. Light is made up of white, which is broken down into red, orange, yellow, green, blue, indigo, and violet. When light hits a surface, all of the light except the colour of the item gets absorbed into the item. The other colour bounces off into our eyes or onto other things. When light hits white, most of the light is reflected, save it gets weaker, so white is all of the colours. Black absorbs all of the colours and usually doesn't reflect any, instead absorbing it all. That's why wearing black gets you hotter why wearing white gets you not so hot. Since blue has the greatest wavelength, it is the strongest, and is the second hottest item of clothing, usually. Violet is the weakest. Green is the center point.)

(Not exactly.

The brain/eyes can interpret the combination of as few as three specific wavelengths as "white." True "white," made up of all visible wavelengths at a saturating intensity, can be broken down into an infinite number of color wavelengths, which in reality is unattainable: even the sun has peaks and valleys in its spectrum due to its elemental make-up, and "saturating intensity" is somewhat subjective, and might even be defined as either infinite or simply where your brain has set your eyes' "white balance" at.

Violet is "stronger" than blue, not weaker, at about 0.400 micron wavelength, and is in fact the strongest visible wavelength. Blue has a 0.475 micron wavelength. Just below violet is ultraviolet, which we can't see, and is actually strong enough to cause florescence, as well as give you cancer as the wavelengths are small enough to break the chemical bonds in DNA.

Red is the weakest visible wavelength, at about 0.650 microns. Green is in fact the center point of visible light at about 0.510 microns, and as a bit of trivia, it is green that the eyes use to determine how bright something is (the brain can default to other colors when green isn't present) which is why night-vision optics are traditionally green, and tail lights are red (red won't blind you as easy because it's a weak wavelength, it has nothing to do with the fact that red is a psychological "warning" color).

Something that appears completely white can in fact get very hot in the sun if it absorbs infrared, which is beyond red, up to 1 mm wavelength. Infrared is commonly referred to as "heat" but that's not entirely accurate. Many articles of clothing that appear black actually reflect infrared. I am personally unsure if that is by design.

The traditional thinking of "color" is different with light than with pigment. The three primary colors for light are red, green and blue (magenta, green and cyan), and the primary colors for pigment are red, yellow, and blue. Pigment interacts with light by removing wavelengths only (which was basically already said). Adding colors together in light gets you brighter, and closer to what your brain interprets as "white" as there are more wavelengths present. Adding colors together in pigments will remove more of the wavelengths, making the object darker and bringing it closer to black. The brain's interpretation of the color of an object depends on the wavelengths in the light illuminating the object, the wavelengths removed by the object, and the brain's "white balance setting," which can do very strange things if the illuminating light is made up of a dominating pure wavelength.

Black, white, and all shades of gray are not colors because they do not have specific wavelengths. They are an intensity of a multitude of wavelengths and harmonics (electromagnetic "white noise") within the visible spectrum.

Aluminum is one of the most highly reflective materials in the visible and infrared wavelengths (at least, it probably goes beyond that). Even so, it is only 96% reflective, meaning it on average absorbs 4% of the light that contacts it.

A "photon" is not a particle, but acts very similar to one. It is actually an electromagnetic "pulse" at a specific frequency sent by a an electron changing it's orbital energy level.

The wavelength of light emitted or absorbed by an element is determined by the electron orbits of the atom. Each element has a unique signature determined by the electron orbits. A "photon" is emitted when a electron moves between orbital energy levels. The frequency is determined by which orbit the electron is dropping from/to. This frequency will also determine which colors the element will absorb. As an example, copper will burn green in flame. If an atom is excited (i.e. by friction from temperature) an electron may be bumped into a higher orbital energy level, and when the electron drops back down a "photon" is emitted. Likewise when a photon hits an atom at it's electron orbital frequency, the electron will absorb the "photon" pulse, exciting the atom into mehcanical energy (i.e. it will raise the temperature). This is why light will heat up objects that absorb the color of the object.)

-Calan works on telescopes.

The "Tell Me a Trivia Or Two About Yourself" Threa

The "Tell Me a Trivia Or Two About Yourself" Threa

The "Tell Me a Trivia Or Two About Yourself" Threa

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