Ghosts and Clouds

I love seeing the world through my boys eyes.
This morning, it was really foggy when we dropped
Josh off at his science camp. So, foggy that we were
literally walking through it. The fog got Caleb's wheels
turning. He asked, "mom, are ghosts made of clouds?'
Of course, I said "no." Caleb then asked, "So, what are they made of then mom?"
I said moisture. He continued and ask, "If ghosts are not made
out of clouds, then what are they made of?" I responded ghosts are made of spirits.
I can see the connection. I'm not sure if I pacified his curiosity but I answered
the best I know how.

Here's the scientific answer on what clouds are made out of. It's kind of interesting.

Basic definition

A cloud is just water in gaseous state, it is just vapor.

It is the combination of condensed moisture with dust particles in high energy state. Fog is the lowest cloud one can reach. When one sees fog, they see a cloud.There's no difference at all.

A more complete answer

Fog or Mist, cloud of condensed water vapor in the form of water droplets or ice crystals, suspended in the atmosphere.

Fog clouds can be seen in cities and industrial areas combined with smoke to produce the mixture called smog.

Meteorologically, fog can be classified into four general types according to the mechanism by which it is formed: advection, radiation, up slope, and precipitation.

Advection fog is formed whenever a current of relatively warm, moist air passes over a colder body of land or water. Fog of this type is frequent in the winter when snow is on the ground. It is also common over the ocean, as in the North Atlantic when winds blow across the warm Gulf Stream and reach the cold Labrador Current.

Radiation fog, formed only over land, is caused by the cooling of the earth by radiation. At night, radiation lowers water temperature comparatively slowly, but land cools rapidly, becoming cooler than the air above it; consequently a fog is formed. Such fog is seldom thick and usually burns off in the morning.