We need to sleep for a number of reasons. Sleep is not just a period of doing nothing – in fact, the body is very active during sleep, but in a different way. Sleeping helps us process our memories better – which is why children need more sleep than adults: they have to learn so many new things! It also allows our bodies to recover, and it literally clears our minds – turns out that the waste products from brain cells are cleaned up best during sleep. Useful!