A binary tree is like a big family tree. It's made up of lots of circles (called nodes), with lines connecting them. Every node can have two children. So each node can be split in two - like a tree! The topmost node is called the root and the nodes at the bottom are called leaves. To find something in a binary tree, you start at the root. From there, you look at the two children and decide which one probably contains the information you're looking for. If that one doesn't have it, you can move to one of its own children and so on, until you get to a leaf that contains the information.