What make water vapor float in the air as cloud though they are heavier than air?

Question

Water is heavier than air but in its water vapour state it float and rises as clouds and stay afloat trillion of tons of it? Why? What physic explanation is there for it scientifically? It bewildered me.

Answer 1

"The vast majority of clouds you see contain droplets and/or crystals that are too small to have any appreciable fall velocity. So the particles continue to float with the surrounding air. For an analogy closer to the ground, think of tiny dust particles that, when viewed against a shaft of sunlight, appear to float in the air."

Answer 2

The water vapor in a cloud is heavier than the air around it and floats as low as it can. However, the air around it is lower in pressure than air at ground level. This air is also cooler. It floats on top of warmer, denser air at the surface. Moist air rises from the surface because it is heated like a hot air baloon. The air in the baloon is ordinary air which has decreased in density because it is heated. The baloon rises and so does the heated air. As it gets higher, the pressure drops and the temperature falls. The falling temperature causes moisture in the air to condense into droplets. Clouds look very dense, but they are nothing but masses of fog. The illusion relies on the enormous size of the cloud and the fact it a mile or more away. Clouds have flat bottoms and puffy tops because the bottom is the exact height at which the water begins to condense. Above this height, the air continues to condense and this builds up the top of the cloud. Clouds form over spots on the surface which are hotter than the surrounding ground. If the cloud drifts away from this spot, the air stops rising and the cloud begins to dissapear. If the spot stays warm, a new cloud can then begin to form.

Answer 3

Depends on the cloud. Convection clouds (cumulus, the little fluffy ones), are formed when hot moist air rises and cools forming the cloud, when the vapour is cooled it sinks back down again and evaporated, although the coloud is stationary its content is constantly being cycled. Also, in these clouds the condensation releases heat, which causes the vapour to rise to even colder heights, condence more, rise higher, condence etc. thus on a still day they can reach massive heights.

In cumulonimbus clouds (and others), the convection currents can move the clouds material around for ages, hailstones have been blown around inside these clouds for ages.

Although they may look simple and cute, clouds are complex dynamic entities.

Cheers for listening,

Lucas - Against blue sky thinking

Answer 4

A water *molecule* only weighs 18 (16 for the oxygen, 2 for the hydrogens. Most gas molecules (nitrogen, oxygen) weigh almost twice as much. Only when they condense (start sticking together) do they start to weigh more than the air in the volume of space they occupy

Answer 5

water vapor has less density than air most of the time. the density of air changes with its temperature. if the air where the steam comes out the stack is cold air then the hot steam is going to rise. but i have seen fog which is also water vapor hugging the ground, not rising at all
http://en.wikipedia.org/wiki/Water_vapor#General_properties_of_water_vapor

Answer 6

water vapor is in a gas state not a liquid state and as gases are lighter than air, water vapor rises.

remember the 3 states of matter: solids, liquids, and gases. Water as a solid (ice) and as a gas (vapor or steam) are lighter than liquid water

Answer 7

Cohesion and density play a major part. The vapor forms a loose magnetic bond with other molecules, and the formations are a result of low density. Density plays a major part in buoyancy.

Answer 8

HEAT. Earths surface heats up, heat rises creating thermals. Why do hot air ballons rise !

Answer 9

it's a heated gas, so it rises. That's the simple explanation.

Answer 10

There are two things you really need to do. learn the english language just a bit better, and your own homework.