Why does a fan wing appear blue on one edge and yellow on the other?

[ashishsinghal]

Right now (1600 IST, 3 march) I am sitting on my chair. When I look at the fan at a specific angle (about 75 deg) I can see a blue colour at one edge of the wings and yellow colour at the opposite edge of the same wing.

In my room there is one source of natural light and one white artificial light(on adjacent wall). This wing is pointing towards the corner which is common to both the walls.

The edge towards artificial light is blue and the one towards natural light is yellow. Also I must mention it is early in the evening and artificial light is stronger than natural one.

Can anyone please answer why is this happening? I am quite amazed by the sight.

 

[LostConjugate]

I would guess small particles on the edge of the wing are scattering the blue light. Higher frequency light has an exponential chance to scatter.

 

[davinstewart]

If you're wearing glasses and looking at the fan at an angle, it could be chromatic aberration due to the refraction through the glass. I get that often when I wear glasses ... yellow on one side and blue on the other. It should be exaggerated when you increase the angle and reduced when you look at it straight on.

 

[Archosaur]

How fast is your fan spinning? It could be red/blue shift.

</joke>

 

[ashishsinghal]

If you're wearing glasses and looking at the fan at an angle, it could be chromatic aberration due to the refraction through the glass. I get that often when I wear glasses ... yellow on one side and blue on the other. It should be exaggerated when you increase the angle and reduced when you look at it straight on.

Yeah I wear glasses, and your point seems correct but can you just explain in more "simple" words other than chromatic aberration. Thanks

 

[Archosaur]

Yeah I wear glasses, and your point seems correct but can you just explain in more "simple" words other than chromatic aberration. Thanks

It looks like we have a winner! Good call, Davinstewart (and welcome to Physics Forums). Chromatic aberration is based on the property of light that says that different colors bend different amounts when they go through the same lens. So, white light can be separated into different colors.

[PLAIN]http://upload.wikimedia.org/wikipedia/en/4/47/Lens6a.svg

 

[ashishsinghal]

What does it have to do with the edge of the fan? Why is a specific side yellow and the other blue? And why yellow?

 

[Archosaur]

Good questions. The colors you're seeing are blue and yellow because they have the highest and lowest wavelengths (respectively) in the particular "white" ambient light of your surroundings.

As for blue being more dominant on the top and yellow being more dominant on the bottom, I suspect that's because your lenses are not symmetrical (unlike the lens I showed as an example). Essentially, your glasses are acting as a prism.

 

[ashishsinghal]

As for blue being more dominant on the top and yellow being more dominant on the bottom,

They were not of the case top and bottom. They were at the same horizontal level. The one towards artificial light was blue and the one away was yellow.

Also, I am talking about white light, so shouldn't the lights be blue and red?

 

[rcgldr]

Note that a spinning black and white disk can create the illusion of color, but not sure if that is related to the fan.

http://www.exploratorium.edu/snacks/benhams_disk/index.html

Some artifical light sources, like flourescent bulbs, cylce in brightness and color, causing colors to been seen in fast moving objects.