Why is it like this?

[Sefrez]

I understand that laser light is different than sun light or light bulbs. But why does laser light have a sand like texture if not focused in a small area?

It almost looks like the "sand" pieces are floating about 20 mm off the surface.

Sorry if this is a nub question. :

 

[Things]

Its due to a thing called "Speckle". All lasers have a form of speckle, so when you shine it on your roof or whatever, it scatters the light around the room. You end up with a bunch of little speckles of green and black. SInce laser light is monochromatic (Only 1 single colour), you will ONLY get green and black speckle.

 

[pullbangdead]

http://en.wikipedia.org/wiki/Speckle_pattern

 

[Justin]

This is an interference pattern caused by waves of light interfering with one another. Look up "interference" in reference to waves to understand more. This effect is only present with monochromatic light, so lightbulbs and the sun will not produce noticable interference.

 

[steve001]

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