How to spot the limit of a scientific model
Work like a scientist rather than a memorization machine: start from one observation, make a prediction, test it, then refine the model.
Start with a question
Write down what you are trying to explain or calculate. Name the quantities, particles or observations before choosing a formula.
Use a small example
Choose simple values or a familiar element. Change one variable at a time and predict the direction of the effect before calculating.
Check the science
Verify units, sign, order of magnitude and assumptions. If the result contradicts the physical story, investigate before accepting it.
Then go deeper
Move from the simple model to exceptions, uncertainty and more realistic behaviour. Exceptions are often where the most interesting science begins.
Explain the idea in your own words. If you can predict what happens before calculating, you are already doing more than memorising.