Children need around 10 hours of sleep each night. Muscle coordination and control are uneven and incomplete in the early stages, but children become almost as coordinated as adults by the end of middle childhood. Small muscles develop rapidly, making playing musical instruments, hammering, or building things more enjoyable. Baby teeth will come out and permanent ones will come in. Permanent teeth may come in before the mouth has fully grown, causing dental crowding.
Eyes reach maturity in both size and function.
Mental Development Children can begin to think about their own behavior and see consequences for actions. As children near adolescence, they master sequencing and ordering, which are needed for math skills. Children begin to read and write early in middle childhood and should be skillful in reading and writing by the end of this stage. They can think through their actions and trace back events that happened to explain situations, such as why they were late to school. Children learn best if they are active while they are learning.