I started a thread a long while ago about this, but here it is again as I believe I have more concrete "evidence"
first:
http://en.wikipedia.org/wiki/Inverse-square_law
explains the law in detail
that is from the caption of the picture...
Notice how it says that it is BASED of the formula for surface area of a sphere... as you double your distance from the OMNIDIRECTIONAL source point, it makes sense that the light given off from the point would be reduced by this formula because now it has to cover a larger surface area (based on the sphere surface area formula)
Every time I see a indoor grow on this site, with a hood / reflective material on the wall / and the light source way up high you get people saying "oh man lower the light and you'll double your output"
The above ALONE disproves this completely.
yeah you have your source point S, but the thing is, you have a hood reflecting all those flux lines back towards the plant. then you also have all those flux lines bouncing off your reflective side walls...
we are REFLECTING those flux lines with the hood, the reflective walls, etc...
Now, the only thing that is diminishing the strength of the field, is the loss of energy from reflecting, and distance travelled THROUGH the medium (air)
or another way,
the hood and reflective walls in a room of LxW will keep the density of the flux lines CONSTANT given infinite distance (Height)*
* again, energy lost from traveling through the medium (air) and reflecting off of not perfectly reflective walls will diminish the returns. also from the link:
first:
http://en.wikipedia.org/wiki/Inverse-square_law
explains the law in detail
This diagram shows how the law works. The lines represent the flux emanating from the source. The total number of flux lines depends on the strength of the source and is constant with increasing distance. A greater density of flux lines (lines per unit area) means a stronger field. The density of flux lines is inversely proportional to the square of the distance from the source because the surface area of a sphere increases with the square of the radius. Thus the strength of the field is inversely proportional to the square of the distance from the source.
that is from the caption of the picture...
Notice how it says that it is BASED of the formula for surface area of a sphere... as you double your distance from the OMNIDIRECTIONAL source point, it makes sense that the light given off from the point would be reduced by this formula because now it has to cover a larger surface area (based on the sphere surface area formula)
Every time I see a indoor grow on this site, with a hood / reflective material on the wall / and the light source way up high you get people saying "oh man lower the light and you'll double your output"
The above ALONE disproves this completely.
yeah you have your source point S, but the thing is, you have a hood reflecting all those flux lines back towards the plant. then you also have all those flux lines bouncing off your reflective side walls...
A greater density of flux lines (lines per unit area) means a stronger field.
we are REFLECTING those flux lines with the hood, the reflective walls, etc...
Now, the only thing that is diminishing the strength of the field, is the loss of energy from reflecting, and distance travelled THROUGH the medium (air)
or another way,
the hood and reflective walls in a room of LxW will keep the density of the flux lines CONSTANT given infinite distance (Height)*
* again, energy lost from traveling through the medium (air) and reflecting off of not perfectly reflective walls will diminish the returns. also from the link:
The total number of flux lines depends on the strength of the source and is constant with increasing distance.
so we will still lose energy if they are higher up, but it is NOT based on the inverse square law...
Discussion welcome!
I'd like to hear others thoughts.
EDIT:
shine a laser in your eye at 2 ft, and it's bright as hell, shine a laser in your eye at 20 ft and it is still bright as hell. (not 100x less bright)
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