/sci/ - Science & Math

faggotry
most like

>>11511215
>What is causing this phenomenon?
Phosphorus of different colors have different half-lives.

>>11511236
>attention whoring namefag
Yet another entry in my filter

>>11511236
Explain a little more

LCD TV?

Do you also have a LED bulb in the room?

IF you turn off the light and just have the TV, is the rainbow still there?

>>11511247
The rainbow is there with just the tv. It's only visble when the screen has a decent amount of white light. If it's an orange reeses commercial the rainbow disappears.

>>11511215
Television emmits only a couple colors, usually Red, Green, Blue. It's also done in pulses, faster than your eye can detect. I'm guessing each blade has curvature and different parts of the curve reflect different wavelengths.

>>11511240
Simplifying: Among the 3 primary colors of your TV, one color stops before the other 2, then the other one stops before the last one. This changes the overall color of the light the TV emits in cycles which –as you observed–, have a stroboscopic effect on your fan.

>>11511259
>I'm guessing each blade has curvature and different parts of the curve reflect different wavelengths.
This is unlikely to be the case. It would mean the blades are colored and that could be seen under normal illumination.

>>11511259
Thing is, there's the whole roy g biv spectrum visible. It seems like some kind of dispersion is happening rather than some artifact of the operation of the tv.

It's not phosphors. No one has a CRT anymore.

It has something to do with a cohesive light front and the angle of the blade with respect to your eye, and its reflectivity.

I wouldn't think it had anything to do with the TV other than the frequency and the cohesive wave front, because each pixel has a red blue or green composite and makes white by blending the intensity created by the angle of polarization. If it were the color of the TV you wouldn't see the whole rainbow.

>>11511215

I'm betting if the fan were off, the reflection of the TV on the blade would be a vertical white line and very thin.
As the blade turns, it sweeps the white line across the blade, which due to persistence of vision would make the whole blade light up

But the angle of the blade to your eye reflects only a portion of the spectrum.

Since the light is strobing as the blade is turning, the persistence doesn't blend the colors into simply a white reflection across the whole fan blade.

>>11511215
Jews, unironically.

>>11511297
>It's not phosphors. No one has a CRT anymore.
You wouldn't even get this with a CRT TV.

LCDs don't flicker like this.

My guess is op probably has a DLP projection TV. Spinning colorwheels in the cheaper ones, and you can see color flicker. See pic.

>>11511613
Pretty clearly the right solution here. The only other time scale in the problem similar to the time scale of the fan.

>>11511260
Subtler versions of the same effect are noticeable even with fluorescent tubes, since while the phosphors in those are mixed, and not the same as those used in CRTs, they have different half-lives as well. Most point-and-shoot cameras with a "sport" mode for taking video can show this clearly.

>>11511215
Considering the leading edge is further from you and the opposite edge is closest (so it pushes air toward you) I'm guessing a Doppler effect.
Technically it's shooting regular white at you but the further away blade edge takes a bit longer, giving the illusion of a stretched wavelength, or at least that's what your eye catches. I bet if the blades were flat there'd be no color spectrum.
What if you stand perpendicular to the blade angle? Does it still doing spectrum?

Also either your eyes or the TV flicker are refreshing at a very close rate to the blade revolution. Blade spins 370° (to a 10° position), refresh frame, another 370° (to the 20° position), refresh frame, etc. So it looks like it's spinning only 10° at a time rather than a full revolution.
I pull these numbers out of my ass, but you get the idea.

>>11511673

>>11511613 ,here. Would have been nice if OP could have taken a pic/included model of the TV. Spec datasheets are useful.

>>11511684
Had a fluorescent light like this. Mesmerizing for a kid. As I recall, pretty sharp pulses in magenta-ish and cyan-ish colors at 60hz. Looked neat.

>>11512329
Relativistic fan blades?

>>11512360
>Relativistic fan blades?
This is the kind of mistake people commit when they get their knowledge of physics from popular science treatments.

>>11511215
The flicker fo the RGB channels is not perfectly synchronized, easily possible, especially common on projectors.

>>11512360
>Had a fluorescent light like this. Mesmerizing for a kid. As I recall, pretty sharp pulses in magenta-ish and cyan-ish colors at 60hz. Looked neat.
120 Hz because there is one peak and one valley in every cycle. These days electronic ballasts are popular, which use a frequency too high to leave any significant flicker.

>>11512382
The 60 Hz mention was generic. Never sure if the colors were due to instantaneous voltage (which would be 120Hz) or polarity (60 Hz). Old, slightly unreliable T-9 circle tube. I think I could still science it out, the light is still at the parent's place and works, but that's 500 miles away. In a pandemic. And Op hasn't told us which TV he has.

>>11511255
TV emit polarized light. Polarized light can easily cause birefringence

>>11512584
There is no birefringence in colored fan blades for reflected light.

>>11512584
to be more precise, LCD TVs have a polarization film on them. If you removed this you literally wouldn't be able to see the TV.

When some surfaces reflect light, they polarize the light they reflect. If the light it's reflecting/polarizing is already polarized it can cause double refraction, aka birefringence.

Apparently your fan is polarizing light as it reflects it.

>>11512584
to be more precise, LCD TVs have a polarization film on them. If you removed this you literally wouldn't be able to see the TV.

When some surfaces reflect light, they polarize the light they reflect. If the light it's reflecting/polarizing is already polarized it can cause double refraction, aka birefringence.

Apparently your fan is polarizing light as it reflects it

>>11512360
It's an emerson pl-p42w-10a plasma tv from like 10 years ago, that's all I know.

>>11512826
>plasma tv

Whelp, that throws all the speculation in this thread out the window. Plasma TVs are a blasphemous technological art. As a wild-ass guess, maybe the color fields are sequential for less electrode cross-talk between sub-pixels.

Op, try placing the fan between you and the TV. What do you see?

>>11511215
OP the good news is you have unwittingly rediscovered gaydar

the bad news...

>>11511215
Good post. Here's where you should've made it: >>11492814

>>11513838
By electron decay do they mean some weak interaction or just electron changing state to ground?

>>11514021
*sigh*

>>11514021
ground state