This is resonance: Imagine an system composed of a mass hanging from a spring, like this [1]. If you pull down the mass and release, the mass will move up and

This is resonance: Imagine an system composed of a mass hanging from a spring, like this [1]. If you pull down the mass and release, the mass will move up and down (oscillate) at a set rate (the system's natural frequency). No matter how far you pull down the mass before release (the amplitude), the system will always oscillate at the same frequency. Now, imagine you start pushing on the mass (applying forces) while it is in motion. If you were to push up on the mass while it is traveling down, you would decrease the distance the mass would move on subsequent oscillations (damping the amplitude). But if you were to push up on the mass as it travels up, you would be increasing the amplitude of oscillation. That is what we call resonance. [1]: https://i.ytimg.com/vi/lZPtFDXYQRU/maxresdefault.jpg https://i.ytimg.com/vi/lZPtFDXYQRU/maxresdefault.jpg