When I turn on my fan and I feel something ‘hitting’ me, what is that? Is my fan just moving particles around in my general direction? When I feel an air current, what is actually coming into contact with my body?
In: Physics
Yes. But, you’re feeling a macroscopic (the larger scale) effect of many atoms (actually mostly diatomic molecules like nitrogen in air) hitting your skin. This is what pressure physically represents with gases. It is the force imparted by the collision of molecules against the walls of a container or surface. And this is in-fact the case when there is no wind. You can sense pressure as a tactile experience. But you are constantly experiencing a pressure which your body has adjusted to (it provides you with no helpful insights into how to survive as an organism if you simply feel the background atmospheric pressure). Some times the pressure changes suddenly, this is usually why you can sense it’s going to rain or there is going to be a storm.
Air molecules. About 78% nitrogen, 21% oxygen, 1% other stuff.
The fan is pushing air towards you. The air molecules are running into you. You feel them bouncing off you. Physically, it’s exactly the same thing as the force you feel when someone aims a water hose at you, but air is way less dense than water so the force is a lot smaller.
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