When we are asleep our brain does not switch off. It keeps working, but not as hard.
The most interesting part of our body that changes during sleep is our brain.
Niamh, age 7, wants to know why we have scary dreams. But after 200 years of study, dreams are still very much a mystery.
The theme of this year's NAIDOC week is "Our Languages Matter". Aboriginal languages under threat across Australia. Read a Warlpiri introduction to Dreamtime and The Dreaming.
Sleep is often overlooked as a treatment for brain injury, but new research could be about to change that.