Are children's saxophones as big as adults'?

The size is different. Children's saxophone refers to bB's mini-elbow. Its principle and pitch are exactly the same as bB's tenor straight saxophone, and both belong to tenor saxophone, resulting in a smaller volume than alto saxophone, so it is also called children's mini-elbow saxophone. In fact, bB elbow saxophone is not suitable for children, because its breathing style is difficult to master and it takes some time to get used to it, so children get bored easily.