Sounds very technical ... duh... but can it actually emit a beam of green light????

Yep! A beam of light of exactly one frequency ... of your choice.

I would like to see that.

I've seen this (not counting just green, and leaving out white) about a hundred different places today - on the power supply to my laptop there is an LED power indicator, the brake lights on some vehicles, on my phone there are charging and 'new message' indicators, on the computer at work the buttons are illuminated with LEDs, the stop lights at the intersections, on my ridiculously over-done laptop there are no fewer than fourteen LED indicators, on a LED keychain fob, on the toaster, on three different battery chargers, on this silly toy this girl was using to make her teeth light up different colors, on this 'mood lighting' ball, on an alarm clock....

Edit: http://www.google.com/images?um=1&hl=en&safe=off&rlz=1C1_____enUS394US397&biw=1280&bih=685&tbs=isch:1&sa=1&q=led+green&aq=f&aqi=&aql=&oq=

Although the leds will emit light over a narrow band, it is still a bandwidth. To get a single frequency you need to use a laser.

http://www.google.com/images?um=1&hl=en&safe=off&rlz=1C1_____enUS394US397&biw=1280&bih=685&tbs=isch:1&aq=f&aqi=g10&oq=&q=green%20laser%20pointer

Okay, when I shut off my computer monitor the green (yellow-green)light goes dark and the glass actually looks a dark red. So the class is not a filter that makes the light green. Right?

Unless you have a REALLY old CRT that is meant to have a green screen only... then maybe.

Right. If you have a CRT you are dealing with glowing phosphorus and a red, green, blue dot matrix from a color gun.

Flat screed is usually led or plasma.

My father is the same way. I used to bring all my 64 crayons and ask him to separate the colors. haha It was a mess. Its interesting that only boys can be color blind and girls only carry the gene.

Gota love those Light emitting diodes.

A diode is a semiconductor with a specific energy gap that associates with a given range of frequencies. The electron drops into the hole and releases photons with that range of frequencies, for a green led it falls within that range of the visible spectrum.

Clumsy falling electrons done it! Just remember when electrons drop from a higher energy shell to a lower one they always must emit energy. Energy conservation FTW!

but, what color then is infrared?

lasers are monochromatic (mostly)

there are no green laser diodes. all green laser diodes are just frequency doubled red lasers (otherwise we could have some awesome laser video projectors)

lasers are temporally AND spatially coherent

who knows what is going on in every one else's tiny little brains. what my mind perceives as green could be paisley in yours

The better to pull the wool over their eyes.

Color is the perception of light, ie infrared is no color as it is not perceived by the ocular nerves becuase the rods and cones are not sensitive to its frequencies.

hahahaha

light, color, heat, radio, microwaves, gamma rays

its all the same thing

at one end of the spectrum the magnetic component is stronger and at the other end the electric component is stronger (the electric and magnetic are 90 degrees out)

and don't get me started on S-rays and P-rays and brewster windows

Heat energy is definitely not the same thing as light, or color. Light can be absorbed and its energy turned into heat, however the energy can no longer be called light after the transition.

Heat is not the same as temperature. In physics heat is always the transfer of energy between systems, where as temperature can be used to measure the energy of a system.

When two particles smash into each other kenetic energy will be transferred, the motion of the electrons will cause infrared energy to be released however that does not make the energy transferred via kinetic interaction light energy, ie just because some of the by product ends up being light, does not make light the same as the heat energy transferred. The distinctions are subtle but end up being extremely meaningful.

That is actually not quite correct. Particles do collect kinetic energy from banging together, absorption of photons, etc., but the bandwidth of infrared is definitely heat energy. Of the three basic forms of heat transference we normally deal with, conduction, convection, and radiation, the radiation of infrared is a basic and common form of heat dealing with a specific bandwidth of the electromagnetic range.

There is little difference between a resistor who radiates infrared as a way to reduce voltage to a desired level and a LED who radiates visible light as the desired by product of friction loss of electromagnetic radiation in the electric bandwidth. Electricity in ... heat and/or light out.

Infrared heat CAN be the same as temperature if that is the measure one is seeking. This concept is used in lab equipment, oven design, some aspects of astronomy, and various other systems where the production of infrared is linear to the object, device, or substance measured.

Some systems, such as heating a bar of steel, will go through a non-linear heating bandwidth with the change of temperature followed by a increasing frequency of released EM radiation. In this case the temperature is gauged by the color of the radiation emitted. In other systems it is just the number of infrared photons that are emitted to give a temperature.

Robin's comment about light, heat, electricity, color, microwaves, gamma rays ... was correct.

Kinetic energy is energy too but is usually measured by heat content such as a BTU or mass velocity.

Note that a human body is designed to feel heat as in infrared from the Sun. It cannot feel green light nor the ultraviolet that burns the crap out of your skin. When feeling heat it is counting infrared photons not measuring the temperature of the Sun in millions of degrees.