Eventually dust particles end up on the floor or on furniture. But many stay in suspension in the air for long periods of time before falling. What forces hold them up temporarily?
2007-03-26 23:45:19 · 7 answers · asked by Daniel C 1 in Science & Mathematics ➔ Physics
They are colliding constantly with air molecules and other, smaller particles of dust that cannot be seen by the eye.
2007-03-26 23:48:43 · answer #1 · answered by Life's a beach 4 · 0⤊ 0⤋
Dust is made up of dirt, hair, dead skin cells and other light material usually in small particles.
Dust that is suspended in the air is caught there for similar reasons as to how an aircraft carrier can float on the water or how a seagull can glide in the air.
A good example of dust suspended in the air are clouds. Clouds weigh tons and tons, yet stay suspended in the air. House dust is denser than air, yet stays suspended in the air for minutes when in a vacuum it would fall almost immediately.
Dust stays up in the air for many reasons:
It is light per particle/not dense (but not less dense than air, so that is not the sole cause).
It is in suspension because it is aerodynamically shaped/sized to do so (like wings etc).
It is in suspension because it is being blown by a current of air, whether air conditioning in a house or a gust of wind outside etc.
Air pressure, flow, and more keeps the particles up in the air, but they are constantly in a state of elevation decay (falling), as are all objects acted upon by enough gravity.
Dust particles can also be statically charged. This is not necessarily a cause of suspension, flowing dust, or anything like that, but I'm sure it does have some effect upon the dust and its suspension to a lesser extent.
Clouds that build up significant enough static charges/deficits are (along with the ground as well) the causes of lightning.
But again, I do not think this should be considered the cause of the suspension. The reasons listed earlier should be considered the major causes, in my opinion.
Good Day.
~Tletna
2007-03-27 00:04:12 · answer #2 · answered by xzaerynus 2 · 1⤊ 0⤋
All of the answers given, don't explain why dust particles in zero wind remain aloft. All matter is pulled down by gravity at an equal rate, so there has to be a better answer than wind aerodynamics. I think that there has to be an association to electro-static attraction that acts like a balloon attracting objects keeping the particles airborne.
2015-05-16 16:49:10 · answer #3 · answered by william 1 · 0⤊ 0⤋
in a dust particle it is because of its light weight, flow and speed of wind does not allow it to fall immediately. Take a broad but light weight paper, through it on an windy day, check how much time it took to settle on earth.
2007-03-26 23:56:09 · answer #4 · answered by manjunath_empeetech 6 · 0⤊ 0⤋
dust particles are very light so any wind or even breathing provides the force to keep dust particles floating in air.
Once dust settles it sticks with moisture from air or our skin.
2007-03-26 23:51:04 · answer #5 · answered by X1 2 · 0⤊ 0⤋
Their mass is low enough that air molecules and air currents keep them aloft.
Slightly different scenario but same idea: Large hail balls (sometimes as big as softballs) can be held aloft with this same principle when updrafts are very strong. It is the updraft itself that allows them to get so large. They build layer after layer while being held aloft in the sky and condensed moisture freezes on the outside of each preceeding layer. Amazing stuff.
2007-03-30 22:36:13 · answer #6 · answered by SDTerp 5 · 0⤊ 0⤋
They are so light, air currents due to motion of people, heat currents in the air, breezes ..etc, move them around constantly.
2007-03-26 23:53:49 · answer #7 · answered by Norrie 7 · 0⤊ 0⤋