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Re: [APD] Alternatives to watt/gallon rule

Andrew McLeod wrote:
> On Mon, 19 Sep 2005 22:43:28 +0100, Jerry Baker <jerry at bakerweb_biz> wrote:
>> I have often wondered about applying an infrared blocking film to a
>> shield in extreme cases of MH lighting heating up a tank.
> Probably a really, really bad idea BTW...
> Firstly, the 'heat' that seems to come from a bulb may not just be infrared radiation - all radiation (including visible light) will warm things up if they absorb it (i.e. they are not white/reflective).
> Secondly, if MH's do put out a fair amount of infrared, then an infrared filter will have to absorb all of that radiation - as heat. So if it's enough to warm up your tank, think what it will do to a little bit of film...

I believe the film reflects infrared rather than absorbing it. My 
understanding of electromagnetic radiation is that the energies 
associated with far-infrared happen to correspond with the range of 
energies separating the quantum states of molecular vibrations. The 
result is that absorption of infrared radiation results in molecular 
vibration, i.e. heat. The absorption of visible light by matter is 
associated with elevating electrons to higher quantum states - something 
that does not translate into molecular vibration.

Jerry Baker
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