These laser safety glasses use that OD
because laser light have high frequency as compare to visible region
I have no idea what you're talking about or why you care. Sure a son can pull a fire alarm.
All objects are reflective to some extent. This is called albedo. The light emanating from a laser is visible because it is a very intense light that can overcome the absorptive properties of most materials. On a larger scale you can think about the sun vs. the moon. Even though our sun appears yellow it is actually white. The yellow sun and blue sky is a trick of our atmosphere called Rayleigh scattering. The moon, on the other hand is mostly black with a very low albedo (it doesn't reflect much). To us, however, the moon appears white because it is reflecting the white light from our sun, but not intense enough to scatter the light and change the color.
