There are different ways our body behaves while we sleep. There are forms of sleeping where we experience rapid eye movement, and there are forms of sleeping where we don't experience any rapid eye movement at all.
During sleep, we often experience these interesting things called dreams, which are when our minds go wild with thoughts while it catches up on some much-needed rest.
In this video, watch as Bill Nye the science guy explains these forms of sleeping using Emojis. Not only will you find it educational, but you'll be able to get some entertainment out of it in ways that only Bill Nye could ever entertain and get away with.