(no subject)
Fans...I figured out how they work. No, not the electrical stuff and the motors and stuff...I could probably get that, but that's not the interesting part. What I'm talking about is the air stuff. Why the wind blows.
Think about it this way, ever see those physics problems with a weight sliding down a ramp? Okay, usually, the ramp is stationary, and the block is moving. But see, what if the block was in some sort of bracket or brace that only allowed it to move up and down, and the ramp was on wheels where it could slide/roll? Then you'd have gravity pulling down on the block which would cause the ramp to slide away. This is how those fan-shaped windmills work. Instead of a weight, you have wind. Now then, reverse it, have the ramp pushing where the weight is forced to go up and over it. In the case of a fan, that's what happens. In effect, the air gets compressed as the blade spins (the ramp is pushed.) This compression then expands, which pushes the air molocules "above" the ramp further away. Then you have kind of a slinky effect, compression forcing expansion. This is what causes the air to be pushed away from the fan, making the wind blow.
Now, how this actually cools people is a combination of convection and conduction. Covection is the moving air. Conduction is the air molocules that directly touch your skin or move very near to you. Your body is hot, but heat flows from what is hotter to what's cooler, like how air flows from higher density/pressure to lower density/pressure. If you open an airlock on a spaceship, things aren't "sucked" out, it's the air inside basically "blowing" out. Likewise, this air "sucks" the heat from your body (that is, your heat flows into the air molocules that are less than 98.6 degrees F.) This happens without a fan. What the fan does is once those particles have taken your heat, it pushes then on past and sends another wave of air to you which takes more of the heat, then it likewise pushed on.
So there ya go, all you ever wanted to know about how a fan works. I brought my boxfan up from home last weekend cause it's been warm here, and while I was going to sleep Sunday night, I happened to start thinking and wondered how it works. I'm a physics student, and a fairly intelligent guy, so I should he able to figure stuff like this out...and so I did. ^_^
...and yeah, stuff like this does go through my head all the time, though more often more abstract stuff than this. -shrug- I wonder if that's a good thing or a bad thing...
Think about it this way, ever see those physics problems with a weight sliding down a ramp? Okay, usually, the ramp is stationary, and the block is moving. But see, what if the block was in some sort of bracket or brace that only allowed it to move up and down, and the ramp was on wheels where it could slide/roll? Then you'd have gravity pulling down on the block which would cause the ramp to slide away. This is how those fan-shaped windmills work. Instead of a weight, you have wind. Now then, reverse it, have the ramp pushing where the weight is forced to go up and over it. In the case of a fan, that's what happens. In effect, the air gets compressed as the blade spins (the ramp is pushed.) This compression then expands, which pushes the air molocules "above" the ramp further away. Then you have kind of a slinky effect, compression forcing expansion. This is what causes the air to be pushed away from the fan, making the wind blow.
Now, how this actually cools people is a combination of convection and conduction. Covection is the moving air. Conduction is the air molocules that directly touch your skin or move very near to you. Your body is hot, but heat flows from what is hotter to what's cooler, like how air flows from higher density/pressure to lower density/pressure. If you open an airlock on a spaceship, things aren't "sucked" out, it's the air inside basically "blowing" out. Likewise, this air "sucks" the heat from your body (that is, your heat flows into the air molocules that are less than 98.6 degrees F.) This happens without a fan. What the fan does is once those particles have taken your heat, it pushes then on past and sends another wave of air to you which takes more of the heat, then it likewise pushed on.
So there ya go, all you ever wanted to know about how a fan works. I brought my boxfan up from home last weekend cause it's been warm here, and while I was going to sleep Sunday night, I happened to start thinking and wondered how it works. I'm a physics student, and a fairly intelligent guy, so I should he able to figure stuff like this out...and so I did. ^_^
...and yeah, stuff like this does go through my head all the time, though more often more abstract stuff than this. -shrug- I wonder if that's a good thing or a bad thing...