If water is heavier than air, how can it rise into the atmosphere and form clouds?

As previous answers suggest... liquid water is more dense than air but an H2O molecule is NOT heavier than air (of course air is a mixture of different materials, mostly N2 and O2). If you look at the molecular weight, H2O is lighter than air (lighter than N2 or O2 molecule). It is also a bigger molecule than N2 or O2 so... when water goes into the air thru evaporation, the air (N2, O2, & now + H2O) becomes less dense (it has to expand) therefore it rises.

Just having H2O in the air does not make clouds. H2O vapor is invisible. Clouds form when the H2O vapor in the air condenses (transforms from vapor to liquid), forming very tiny drops that are so small that they stay suspended in the air. What you see is those tiny droplets.

Easy, water that is in a liquid state is part of the process where the water is at a state that is not gas and not solid, when a gas cools to tends to turn to a liquid if the ambient temperature then drops it will start to solidify, in accordance to the molecular and technical status of the gas that is to be made solid.

methane will cool to a liquid if it is cooled enough LPG gas is a means to transport gas in a liquid form that is because gas when cool has more density than when it is in a gas form. water vapour makes up most of the atmosphere as a green house gas, the more the atmosphere heats up due to infrared heat radians the more water will turn to a gas and then rise, it cannot escape the planet and the variable amount of water vapour depends on the amount of atmospheric pressure and the amount of currents that move clouds.

a cloud is a visible sign that water vapour has clumped together in a mass, which is normally formed over the sea, and then cooled and is returned to the land. what causes the water vapour to retain on the planet is the process of gravity, the vapour cannot escape the planets magnetic core and is kept in a spherical form by the way that magnetism engages with the gas medium.

heat becomes dissipated in a large gas volume since that the charged atoms loose there energy and the accelerated atoms then slow down and return to a former state.

Water doesn't rise in the atmosphere to form clouds.

H2O does, IE the Gas.

If you compare the mass of the molecule to carbon dioxide, Nitrogen or oxygen for example, you will see that a water molecule isn't that 'heavy' compared to what constitutes air.

Evaporation. Water vapor rises, condenses, abd forms clouds.