Laser radiation?

[Petrovski]

Ok, so you can see red light. You'll see somewhat the same (less red) if you look at a bright light source with your eyes closed. But I'm not sure how that proves the laser actually penetrates your skin. I think what you see is the diffusion of light in your skin. Do you have a (medical) source that states visible light can actually penetrate the skin? Or are your findings based on this test?

 

[Switch]

It does penetrate skin and tissue.You can see red light if you point it in the side of your head.It reaches your retina Look at the attached picture, it goes all the way through my hand which is not made entirely out of several layers of skin. :

It may not be a beam anymore, it's getting diffused.But your skin is pretty translucent to red and IR.And also reflects a lot of it.That's why 400mW green burns like hell and 3W of IR have to be really focused to be felt.

 

[Petrovski]

Hmmm I'm not convinced, but not so sure about my previous statements any longer. I'm having trouble with your statement that says skin is very translucent to red light yet also very reflective at the same time. That doesn't make sense to me. Need more info, I'll dig into this some deeper.

 

[Cyparagon]

Okay, NOW you're just being facetious. Never did I insinuate humans are optically equivalent to glass. The fact remains, you said:

Wavelengths of visible light are not short enough to penetrate your skin

Which is simply not true.

 

[Petrovski]

And never did I insinuate a human is optically equivalent to a brick wall. I'm not using humor in any way, so how can I be 'facetious'? (had to look that one up, I'm not a native English speaker). And you took my statement out of the original context:

Wavelengths of visible light are not short enough to penetrate your skin and to do damage on a cellular level.

Which simply is true. Visible light will not do any damage on a cellular level like light with shorter wavelengths can do. And I already said I'm not sure any longer about my penetration statement. But since I don't know you I'm certainly not taking your word for it.

 

[Switch]

Well to be REALLY technical

Wavelengths of visible light are not short enough to penetrate your skin and to do damage on a cellular level.

Your sentence is composed out of 2 sentences using the AND operator.This sentence is true if both sentences are true or both are false.Since one is true and the other one is false , your composed sentence is overall false. ;D
Furthermore, visible light doesn't do cellular damage regardless of skin penetration.It wouldn't do damage if you cut your skin open and shine it in your wound either.

I'm just comparing the skin's reflectiveness and transparency to red light to it's relfectiveness and transparency to green light.Green light is absorbed a lot more than it is reflected or passed compared to red light.A red laser can be seen through your hand and is brighter on your skin than a green laser of equal brightness.It's a fact

 

[Petrovski]

Well... I can't argue with that. If you take a strict litteral approach you're right. I should have formulated my sentence otherwise, the skin part should have been left out. For the penetration part, I stand corrected.