Question

air question @Chemistry

Answer 1

why does air move down when we switch on the fan???

Answer 2

is this a Science question?!

Answer 3

kind of

Answer 4

If you observe the wings of fan, they are not flat, they are curved. when the angled blade moves fast they comes into contact with the air, which moves the air away from it, just like a hand fan produces air when moved

Answer 5

but why air moves down??

Answer 6

i think u need to use physics to answer it

Answer 7

Ceiling Fan Spinning Counter-Clockwise: Makes a room cooler by blowing the air downward. When the fan is spinning in a counter-clockwise direction you should feel a cool breeze coming down and around the room.

Ceiling Fan Spinning Clockwise: Makes a room warmer by creating subtle updraft which pushes the warm air near the ceiling down along the walls and into the room. When the fan in spinning in a clockwise direction you should not feel as much of a breeze.

Answer 8

here see if this Web Site helps if not let me know!!!

http://saveenergy.about.com/od/homecooling/tp/ac_usage.htm


Turn On a Fan
In some climates, you can turn the air conditioner off at night and just let ceiling or floor fans provide cool air for your comfort. The energy used by a fan is far less than that of the air conditioner.<br><br> If you live in a warmer climate, fans can still provide a
comfortable breeze. Using the fans at night may allow you to set the air conditioner above 78 degrees saving a great deal of energy. Fans can also help move cool air around the house to ease the work load of the air conditioner.

Answer 9

oh i need an explanation for downward displacement of air.

Answer 10

Ohh u should of told me that lol!! kk hold on! :)

Answer 11

Here try this one !!
http://www.answers.com/topic/convection
Let me know if it helps!

Answer 12

Heat transfer in a gas or liquid by the circulation of currents from one region to another.
Fluid motion caused by an external force such as gravity.

Meteorology. The transfer of heat or other atmospheric properties by massive motion within the atmosphere, especially by such motion directed upward.

Answer 13

?????

Answer 14

oh not that i need reason u havent understood

Answer 15

Consider the fan to be hanging from the ceiling.

The blades of the fan are angled relative to the horizontal plane. When they move there is 'bunching up' of air molecules on the lower side of he blade and a 'thinning out' of air molecules on the upper side of the blade.

Or more precisely, the air pressure on the lower side of the blade is higher than the surrounding pressure and lower on the upper side. The air now seeks to restore equilibrium by air molecules above the fan moving down into the lower pressure area, and molecules under the blade moving down towards the relatively lower pressure area.

These two effects are in the same direction, superimpose on each other and cause a flow of air down.

Answer 16

If you've ever flown in a propeller plane you can an experiment of how this works.

At first when the pilot turns on the propellers, the blades are angled flat relative to the vertical plane in which they sit. The net flow of air due to that configuration is zero.

But they he tilts the blades so they form an angle to the plane, causing a flow of air backwards relative to the angle of the aircraft. This force has an equal and opposite force which acts on the airplane to move it forwards.

When the plane lands, the propellers are tilted in the opposite angle to the vertical plane. This creates a flow of air in the direction of motion which in turn creates a force on the aircraft against the direction of motion, which helps the plane decelerate.

Answer 17

Thank u JamesJ for helping me -_-! :) i have to go now and do my Test bye =)

Answer 18

james but i didnt get y low pressure above the plane and below greater??

Answer 19

Think of all the air molecules as little colored dots suspended in space. As you move the angled blade through the air, you 'scoop up' or 'bunch up' a lot of them under the blade. Do you see this?

Answer 20

got it

Answer 21

And on the top of blade, there is a lower density of air molecules.

Now this means the pressure underneath the blade is higher, and on top of the blade is lower.

Answer 22

k now y air from abo