Study / Models of the physical world
Physics.
Start with something you can see. Ask what would explain it.
Learning notebookA useful physical model connects an observation to a small set of quantities. A wave can be described by amplitude, wavelength, frequency, and phase. Change one of them and make a prediction before looking at the result.
Superposition is a useful place to start: the displacement of two ideal linear waves adds point by point. Equal-amplitude waves with matching frequency reinforce when their phases match and cancel when they differ by half a cycle. The assumptions are part of the explanation.
Material properties offer another way to connect quantities with behavior. Density, viscosity, boiling point, and polarity describe different aspects of a material. Predicting how real liquids mix or separate requires a physical model of their interactions, rather than a simple ordering of their properties.
Questions to explore
Waves & superposition
Follow the relationship between phase and the sum of two waves. State the equal-amplitude, equal-frequency, linear-model assumptions.
Materials & properties
Distinguish density from viscosity, and a visual ordering rule from a prediction about a real mixture.
Model, prediction, observation
Write down what a model predicts, change one variable, and compare the result with the prediction.