Here's how it works:

* Small forces: Even seemingly insignificant forces can contribute to the growth of a wave's amplitude.

* Matching frequency: The key is that these forces must have a frequency that matches the natural frequency of the object or system that's producing the wave.

* Amplitude increase: When the forces and the natural frequency align, the energy from the forces is transferred into the object or system, causing its vibrations to become larger and larger, resulting in an increasing amplitude.

Examples:

* Pushing a swing: If you push a swing at the right time, even small pushes will make it swing higher and higher.

* A glass shattering: A high-pitched sound, if it matches the glass's natural frequency, can vibrate the glass so violently that it shatters.

* Tsunami waves: While earthquakes are the primary cause of tsunamis, the resonance of the ocean basin amplifies the waves, making them incredibly destructive.

Let me know if you'd like more examples or want to explore any of these concepts in more detail!