2006-10-12 04:17:15 · 6 answers · asked by Jondar 1 in Science & Mathematics ➔ Physics
As per aerodynamics the blades of a fan which are slightly bent on the edge are designed to press air containing dust particles.
Therefore the edge of the blade which are responsible for thrusting the air downwards, are more likely to collect dust particles. Hence the phenomenon.....
2006-10-12 04:39:21 · answer #1 · answered by ♪¢αpη' ε∂ïß♪ ♥♥♥♥♥♥♥♥ 6 · 0⤊ 0⤋
The leading edge of the fan blade (or of any wing, or aerodynamic shape) has what's called a "stagnation point." Below that point, all the air goes below the blade, and above that point, all the air goes above the blade.
But right at the stagnation point, the air stops dead in relation to the blade. So if dust happens to be at just that point, there will be no moving air to blow it off. Therefore, dust will collect near the stagnation point.
2006-10-12 04:22:39 · answer #2 · answered by Keith P 7 · 1⤊ 0⤋
If the fan is not in use, dust will gather on the edge(s) of the ceiling fan. If it is in use, dust will not gather on the leading edge, nor the trailing edge.
2006-10-12 04:27:51 · answer #3 · answered by barbara596 2 · 0⤊ 0⤋
At the edge there is air pocket due to eddies. Air does not flow at the edge. this collects dust.
2006-10-12 05:22:02 · answer #4 · answered by sures 3 · 0⤊ 0⤋
You sluff off layers of dead skin and it clings to (being still, somewhat oily in nature) the other particles, and bacteria, and dust mites, in the air naturally, from your; dryer, your dog, your open windows, your dirty air conditioning filters etc... and as the air rests (When the fan it turned off) it settles on any flat surface it can come across in it's descent.
The fan is actually what stirs it up to begin with.
2006-10-12 04:27:10 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Aerodynamics. My guess is that one ONE edge only, the air flow doesn't touch the blade edge.
2006-10-12 04:20:38 · answer #6 · answered by hilmic 2 · 0⤊ 0⤋