A cumulus can look as light as a piece of cotton. However, the USGS offers a calculation that changes the way we look: with a volume of one cubic kilometer and an average content of 0.5 grams of water per cubic meter, we get about five hundred tons of liquid water.
This mass does not form a compact block suspended in the sky. It is distributed in a huge volume, in tiny droplets. Their small size slows their fall; the movements of the air also intervene in their maintenance in suspension. Comparing the cloud to a tank placed on an invisible medium would lead to a bad image.
The impressive figure does not contradict what we see. It describes a very dispersed material, the total mass of which is considerable. The cloud looks light because we look at its shape, not because its water would have stopped weighing.
What we know
Five hundred tons is an estimate for the example described, not the universal weight of a cloud. Do not confuse condensed water with total air mass.
To go to the source
References consulted on September 21, 2026. Linked pages may be in another language.
Signaler une erreur ou apporter une précision
