What Are Clouds? What are clouds made from? The answer is very simple ... they are just a big collection of water droplets. A cloud is really just fog, but it's up in the sky! The heat from the sun causes water in lakes and rivers to evaporate. When it does this, it turns into an invisible gas called water vapour. This invisible water vapour rises into the sky, because it's lighter than air. When the water vapour is high in the sky, where it is cold, it condenses back into water. This is the same thing that happens when water droplets appear on the outside of a cold glass of pop on a hot day. The water vapour in the sky turns back into water droplets. There are often a lot of water droplets, but they are very tiny, so they can float. (They are just like the mist you see when you spray air freshener in your bathroom). As more and more of these water droplets collect in the sky, they clump together and get bigger and bigger. Eventually the millions of water droplets become visible as a cloud in the sky. As more and more water droplets clump together and get bigger and bigger, the cloud looks darker and darker. Eventually, the water droplets get so heavy that they can't float any more, and they fall to the ground ... as rain. The rain ends up in the lakes and rivers, ... and then it starts all over again. This is called the water cycle. Resources