What scientific principle (s) does the toy yo-yo use? Explain in simple words if you can.

Explanation

In my honest opinion I believe that the yo yo toy uses the principle of simple harmonic motion coupled with the principle of conservation of energy

1. The principle of simple harmonic

Explains/describes it to and fro movement up and down and sides ways

2. The principle of conservation of energy explains how it stores energy in potential form (bounces to the hand) and converts it to kinetic energy (bounces away from the hand).