|MadSci Network: Physics|
Hi, I was watching my ventilator (the standing type, fixed grill but the fan itself keeps rotating). As it was just in front of a white wall, I could clearly notice on the FAN ITSELF (I mean the "fan's screen") small bright - dark alternative fringes, so I couldn't help thinking about interference. The fringes were circular around the center of the stationary grill, and as the fan rotated away from me, the fringes themselves kept increasing in number, as if they were coming from the center. As the fan rotated towards me however, the fringes kept going into the center. Once I was directly in front of the fan, there was just 1 or 2 bright fringes around the center of the grill. The lighting was a regular lamp from the ceiling I think. Also, when I stood up right in front of the fan, I could notice that, as the fan was in the east and rotated towards me, as I said, the fringes were being "swallowed" by the center, but just after it began to pass me, going to the west, the few remaining fringes around the center first rotated about 360 degree I beleive, then increased in number, from the center. I'm sure this is a very normal phenomenon, so I hope my description isn't bad... if so, you can open a fan from this type and you will immediately notice what I'm talking about. So, is it interference? But the fringes are on the fan's screen, not the wall... even if so, where are the "slits"? Are they formed as the arms move very fastly relative to the stationary grid, thus allowing small "slits"? Thanks very much
Re: Interference pattern with a fan?
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