Why do car wheels/ceiling fans seem to rotate aniclockwise when seen against a light reflection sometimes ?
411921
stroboscopic effect. This happens when light source flickers. When the frequency of rotationg object and light source match; the rotating object appears stationary. This effect is used in news paper press to read printing defects on very fast progressing printed material. When the frequencies differ; the rotating object appears rotating with speed that is difference of the two frequencies. (light source freq - object freq * number of blades). If the light source frequency is more than that of object, it appears rotating in opposite direction in certain conditions. This depends on number of blades.
1144714
This is the way they reflect light.
217587
First I want to clear up that clockwise is really a 2-dimensional description of rotation, and planet rotation can be viewed in 3D so you can't really describe planet rotation as clockwise or counterclockwise. If you define an "up" and a "down" for the solar system, and then say "when viewed from above the solar system rotates counterclockwise", then the "anticlockwise" description works. For my answer we will assume you have done all this and that the solar system rotates counterclockwise, so there is no confusion from the wording of the question.\n\nThe reason the solar system rotates counterclockwise has to do with the way the gas clouds that created the solar system collided. They didn't collide head on. Think of cars travelling in opposite direction down an interstate hitting each other not quite head on (i.e. the left headlights of both cars smack together). When they do this they will spin out sideways - they will effectively rotate around each other (in North America with the cars driving on the right side of the road, they will rotate counterclockwise when viewed from above if they collide like this). The gas clouds did the same thing and their collision exceeded the critical density needed for gravity to take over and start forming the solar system, and as this matter collapsed to form the sun and planets, the rotation sped up. The rotation these gas clouds got from their collision gave momentum to the rotation of most matter in the solar system; the sun rotates in the same direction as those clouds did when they collided and so does most other things, including all the planets.\n\nSo that is why.
337135
It is because of the air bending the light slightly. Its the same as shining a light through water, but the effects are less pronounced.
911380
because the angle at which the light refracts is too large.
886324
Think of it like this, if you have a car on ice, there is no friction. The wheels will spin, but the car won't go anywhere. If you have a car on pavement, the wheels spin and the car moves. This is  because the friction where the wheel is touching the pavement doesn't move. Instead,the wheel to rotates and the next part of the wheel touches the pavement and 'doesn't move'.\n\nHope that makes sense. I was never all that good with physics.
753244
Think of the wheels as spinning masses or revolving weights, in fact gyroscopes. \nEach wants to turn left or right while spinning but is constrained by it's axis,\nHowever both drift overtime.\nNow add another pair further back and wider apart, and this pair are not on the same line of travel.\nWith four wheels all wanting to drift the resultant direction becomes a straighter line.
440213
That is because the fly IS moving at the speed at which the vehicle is moving. By the way, it DOES NOT hover at the same place. Suppose the fly is a little fast than the car , then it appears to the fly that the wind-shield is moving towards it and it then adjusts it's speed to remain in the same place( if it chooses to). In the same way in all other cases, it modifies it's speed.\n Someone above pointed to inertia. Remember inertia only acts if the fly or any other object is in contact with the moving object. Otherwise it does'nt come into picture.
39217
Usually referred to as the wagon-wheel effect, this is most often seen in movies and on TV. Movie cameras record 24 frames per second, NTSC TV at just under 60 fps, and PAL TV at 50 fps. If from one frame to the next, the repeated discernible features of a rotating object (e.g. spokes or blades) appear closer behind the previous positions than ahead, the brain will assume the object is rotating in that direction. In the case where the new position is superimposed on the old position, the object will appear stationary.\n\nThis effect can also be observed under fluorescent or gas discharge lights (such as those on the highway) because these turn off and on at 120 Hz.\n\nThe effect can also be created by the vision of the observer. This occurs at distinct frequencies that depend on the individual, roughly around 10 Hz and 30 Hz.
416939
There are chemicals in the air and its just how the light might have been bent. There are tons of different atmospheric problems that could have caused that.
966020
Probably due to helicopter manufacturer patented design thing. It doesn't matter as to what direction the rotor should turn for so long as it goes along the direction of the blades.
22182
it is an optical illusion.
741303
It's a lightning bolt, that when you look at your own avtar, it constantly flashes, making it look like there really is lightning. But when you see them as someone elses, the lightning freezes, and it just looks like "cracks" in the picture.
607437
Actually it is a bot more complicated than those answers would show.\n\nThe spinning wheels cause a gyroscopic effect which makes it easier to balance.
641452
opposite force being applied
436092
Normally you have an electic motor driving one tire/wheel and the other tire is forced to rotate with it, because they are pressed together at the tread.
629914
There should be openings for the fans in the back or on the bottom. Just listen and look in those areas to see if you can see or feel the fans spinning. Make sure the area is not blocked when you are using it and being in front of an air conditioner would help. There are also laptop cooling pads that plug into the USB port that you might be able to find.