Clouds are not made of visible water vapour

A cloud is not a solid bundle. Its visible part consists of tiny water droplets, ice crystals or both. Water vapour, by contrast, is water in its gaseous state and cannot be seen: that is the central distinction in NASA’s explanation. [1]

The Met Office describes condensation: the change from gas to liquid. When moist air cools sufficiently, some of its water vapour can become droplets. These form around very small particles already present in the air. [2]

NASA’s GPM explanation also reminds us that a cloud contains mostly air. Clouds can contain different proportions of liquid water and ice. An enlarged drawing of droplets is therefore a diagram, not a photograph of a compact object. [3]

Try an exercise invented by our editors. Write two sentences on a sheet: I see a white shape in the sky; I know what it contains thanks to a scientific explanation. Those sentences describe different kinds of work. The first records an observation from far away. The second uses knowledge that cannot come from the outline alone. Now draw the cloud’s edge without calling it a sheep or a castle. You can invent a story later; for now, make a description another person can compare with their own. [1]

To continue our editorial workshop, imagine three labels: liquid water, ice and vapour. Make a drawn scene in which the first two have different symbols. Do not use a little white cloud as the symbol for vapour: choose a written label instead. This is a convention invented for our activity, not a way of making the gas visible. Add a small key and ask a classmate to explain your drawing. If they mistake a symbol for a photograph, make the key clearer before asking again. [3]

Our final suggestion is to compare two descriptions: what seemed right before this reading and what you would write now. You do not have to erase the first one. Put them side by side and circle the word you changed. Your notebook then preserves the learning process as well as a tidy answer. We are not making a weather forecast here: one drawing of a cloud cannot tell us what tomorrow will bring. We are practising how to revise a mental picture using a precise distinction and a source we can check. [2]