You can keep repeating this fallacy, but it's simply not true.
https://www.apogeeinstruments.co.uk/conversion-ppfd-to-lux/
But when science does not agree with you and I have made measurements that prove you are wrong I'm not inclined to take your word. Since there is no evidence to support you claims our discussion is over.
You have give us measurements which clearly demonstrated without a doubt that inverse square does not apply to the height of the fixture over the plants. So you have proven yourself wholly and utterly incorrect on your original claim. Or did you get 110umol/s/m2 at 7.93?
So yes our discussion is over. In fact there never was any discussion. This is just the lot of us trying to get some understanding into your stubborn head.
The fact that inverse square is used in the calculation of how the light spreads from a point source, does not mean that your original claim has any validity. You claimed that you need to hang the light as close as possible to the plants because of "inverse square law". Which is bullshit because of reflection and overlap of multiple light sources.
spacial distribution characteristics is also one of the many flaws in the spreadsheet LER QER scenario.
Ah so you do know that it's is possible. LOL. For fucks sake though. Don't drag more bullshit into this. You are also 100% wrong on this claim, but it really is becoming too much. I don't have time to correct all your misunderstood shit.
Anyway, back to spacial distribution. Indeed your calculation is completely useless on that too. Your calculations are simply a textbook example for calculation of a point light source. You "forgot" to add in reflection.
The fact that that didn't matter that much to your calculated values (at least after you manually corrected it all to sort of "match") should have alerted you to the fact that your test was crap. In fact that bend in the line where reflection starts to kick in should also have been a clear indication that something was wrong. That's where the reflection starts to kick in.
The problem is that you only go for confirmation bias and let the cognitive dissonance take care of the rest.
See the bottom bit. That's the almost linear light drop off you will get when you increase the height beyond the height for optimal uniformity.
I personally have written much more complete piece of software to do this type of analysis which does include reflectivity. The reflectivity on your walls is so crappy that I had to drop reflection down to 50% to get anything near your measurements.
Which produces light distribution plans (blue indicates area's with insufficient light for adequate uniformity):
At 3.93
At 6.28:
So from that's is also painfully clear that the fact that you took a strip instead of a full fixture completely skewed the test. Although it's still 100% clear from your measurements that inverse square does not apply the way you claimed it did.
As nfhiggs and I already explained you need to fill the entire canopy with light like you would when you were actually growing plants in that tent. That's the real world test when the overlap and reflection counteracts the effects of inverse square. Then measure the light intensity at the "canopy level". Double the distance and measure again. The light will not have dropped to 25% of the first measurement, but to something related to the reflectivity of your walls.
Try to fact check your nonsense. And use citations when saying I'm the one that is wrong.
I didn't name facts. I'm simply trying to explain to you how to use your middle school textbook physics
How am I going to give citation on the fact that the light will not disappear into the distance when it gets reflected back? Any idiot should be able to understand this.
Try to get past your middle school basic physics and try to understand the more complex situation of reality where there are multiple light sources and reflection. Your own measurements showed that you are wrong and that the rest of us are right. Height is used for uniformity not for intensity. Sure you want the light as close as possible to the plants, but that's to reduce wall losses and not because of inverse square law. You also don't want them too close because then you get poor uniformity with hot spots and dark spots.
Try a better example in your "simulator". Create a fixture of say 100 miles wide and 100 miles deep with a matrix of SMDs uniformly distributed .7" from each other in x and y directions. If you calculate (or measure) the light intensity in the middle of this at 1 foot and at 10 foot, the light intensity will be almost identical. That's why green houses do fine with their lights 4 or 5 meter up in the air. You only loose light at the edges of the grow area where it will disappear on the walls due to less than 100% reflection.
Or alternatively imagine how light travels through glass fiber for kilometers. If Inverse square applies it would run out in mere meters. It doesn't because the light bounces off the walls of the fiber.
