Dr. Mabuse
Septic Fiend
Sweden
9688 Posts |
Posted - 02/21/2015 : 03:36:14
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I followed a link I saw in my Facebook news-feed.
The website "all that is interesting" has an article called 10 Movie Myths That You Probably Believe.
And, yes, you guessed it... it lists 10 common myths which are or are not common in movies.
As a science buff I couldn't help myself noticing that the article writer debunks the laser-myth with more myths...A visible light beam will scatter some of its photons into your eyes so you can see it. This makes it less energetic and therefore less potent. Even basic lasers today—like a laser pointer—uses non-visible light wavelengths. There are several wrongs in there. If the laser pointer were using non-visible light, you wouldn't see the dot of the pointer. Such a laser pointer would be pointless. (pun intended)
A laser pointer with an "invisible beam" isn't using invisible light. The beam still scatter, but the light from the scattering is too weak for the eye to register it. The laser beam scatter when it hits tiny particles in the air, like dust or water vapour. Red beams have larger wavelengths and require larger particles in order to scatter, green and blue laser beams scatter from smaller particles, which there are more of. That makes green and blue lasers easier to spot than red. It's also a matter of intensity. a 5mW green laser may not be visible in daylight where a 50mW green laser will, because ten times as many photons are scattered. Scattering by air, or even smoke as in a disco light show only diminishes the strength of the beam by a minute fraction.
The article author, Radu Alexander is presented as a freelance writer specializes in (among other subjects) scientific topics. But if he can't even get a few short paragraphs on laser right, I'm left wondering how much science he really knows, and how much of a science-communicator he is.
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