How to study physics: a method that works for high school, AP and college (learn each principle as a sentence, draw before you calculate, attempt before you look, keep an error log), how to get better at physics when you are already behind, a weekly plan, and what to do the night before a test

Most students study physics the way they study everything else: read the chapter, highlight it, look at the worked examples, go over the notes. It works in most subjects. It does not work in physics, and the student who does it conscientiously and still fails the test concludes that physics is simply beyond them. It is not. It needs a different method, and the method is learnable in a fortnight.

Why the usual way fails

Physics has very little content. A semester of mechanics rests on Newton's laws, conservation of energy and of momentum, and a few definitions. Reading them takes an evening. The whole difficulty is in applying them to situations you have not seen before, and that is a skill, not knowledge. Reading cannot build a skill, any more than reading about swimming can.

The second problem is worked examples. A worked example shows that each step makes sense, so you follow it and feel you have understood. What it never shows is how the author chose the steps, which is the only hard part. Students who learn from worked examples can reproduce those examples and nothing else, and the test is never those examples.

So the method below is built on one rule: time spent attempting problems counts; time spent reading about them mostly does not.

The method

1. Learn each principle as a sentence you can say

Not a formula. A sentence. "The net force on an object equals its mass times its acceleration, and the acceleration is in the direction of the net force." "If no external force acts on a system, its total momentum does not change." "The work done by a net force equals the change in kinetic energy."

Say them aloud. If you cannot say the principle in words, you do not have it, however well you can write the formula. Nearly every mistake in choosing an approach comes from having formulas without the sentences behind them.

There are rarely more than six or eight such sentences in a unit. Learn them in week one and the rest of the unit is practice.

2. Draw before you calculate

Every problem, no exceptions, however simple. A sketch of the situation, then a diagram of the physics: forces on a free-body diagram, before and after pictures for momentum, energy bar charts, ray diagrams, a circuit redrawn cleanly.

This is not a preliminary to the work. It is the work. The diagram is where you decide which principle applies and what the equation will be, and students who skip it are trying to do that decision in their heads while also doing algebra. Mark schemes at every level award marks for the diagram itself.

3. Attempt before you look

Cover the solution. Attempt the problem completely: diagram, principle, equation, algebra, answer with a unit. Only then uncover and compare. If you were stuck, stay stuck for five minutes before looking, and when you look, read only as far as the step that unsticks you, then cover it again.

The first week of this is miserable, because you will get most problems wrong. That is the point. A problem you got wrong and then understood is the only kind that teaches anything. A problem you watched being solved teaches almost nothing.

4. Keep an error log

A page at the back of your notebook. Every problem you got wrong, in one line: the problem number, and which of four kinds of mistake it was.

After two weeks the log tells you what you are. Most students have one dominant pile, and it is nearly always one of the first two, which means the fix is not more problems but more attention to the start of each problem.

How to get better at physics when you are already behind

Do not go back to the beginning of the book. Do this instead.

1. Take the most recent marked test and sort every lost mark into the four piles above. Twenty minutes.
2. If the biggest pile is "wrong principle": go back to the sentences. Write the six to eight principles of the current unit as sentences, from memory, then check them. Then take ten problems and, for each, write only which principle applies and why, without solving. That is the skill that is missing and it is practised fastest this way.
3. If the biggest pile is "no diagram": for the next twenty problems, draw the diagram and stop. Have someone check the diagrams. Then solve them.
4. If it is math: ten minutes a day of rearranging formulas and solving pairs of equations, separate from physics, until it is automatic. The math in physics is usually a level below your math class; it has to be fluent, not understood.
5. If it is units and signs: write the unit on every line, define the positive direction in every diagram, and check every answer against the picture: a car slowing down should not have a positive acceleration in the direction of motion.

Most students who are behind in physics are behind in one of these, not in physics, and the fix takes two to three weeks once it is the right fix. Why physics is so often wrongly diagnosed is in why is physics so hard.

A weekly plan for a school year

For a regular course this is three to four hours a week. For AP Physics 1 or an honors course, five to six. For college physics, more; plan on two to three hours outside class for each hour in it, most of it attempting problems.

Using worked examples properly

They are not useless; they are misused. The right way: read the problem, cover the solution, attempt it, then compare. The worked example is now a marked answer to your attempt, which is useful, rather than a demonstration to watch, which is not. If you cannot start at all, read the first line of the solution only, cover it again, and continue.

The equation sheet

Most exams give one, including every AP Physics exam. So the exam never tests whether you remember an equation; it tests whether you know which one applies. Study with the sheet beside you from the first week, so that you learn to recognise equations rather than recall them, and so that the sheet is familiar on the day. The sentences from step 1 are what tell you which line of the sheet to use.

The night before a test

Not new problems. Read the error log, redo the three problems from it you got wrong most recently, say the unit's principles aloud, and sleep. A tired student makes units-and-signs mistakes on problems they know how to do, and those are the cheapest marks to lose.

Where it goes wrong, and how to tell

How hard each physics course really is, and a readiness check for the math, is in is physics hard.

Where to get help

A 1-on-1 online physics class with a tutor who holds a master's in physics does the thing a classroom cannot: reads your diagrams and your working, line by line, and tells you which of the four kinds of mistake you make. The first class is a diagnosis from a marked test. For regular and honors physics, AP Physics 1, 2 and C, A-level, IB and college physics, with the error log kept between classes. The free 30-minute first class is a real lesson on the problem you bring.

Questions parents ask

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