Learning
A model is a question you can move.
What changing a simple wave can teach us about a bigger system.
A wave on a screen is not the ocean. It is a deliberately incomplete description of motion. That limitation is useful when it lets us isolate something we want to understand.
Take two waves. At each point, add their displacements. Sometimes they reinforce each other. Sometimes they cancel. Change the phase and the pattern changes, even though the individual waves are still there.
The wave instrument in the Lab is built around that one relationship. It uses a sine wave and a second harmonic. Their sum is plotted directly, without a claim that the drawing is a full physical simulation.
A useful model makes its assumptions visible. It gives you a way to test an intuition, and a reason to ask what you left out.
Devon Akins