Sit next to your child while they do a physics question and listen to the end of their sentences. “Is it B?” “Is it resistance?” Everything goes up at the end, like a question. They’re not working towards an answer. They’re floating one and watching your face. Parents who come looking for an A Level Physics tutor often can’t name what’s wrong, but they’ve heard this and it worries them.
They’re right to worry. But not for the reason they think.
The honest version
A lucky guess and real understanding look identical on a marked paper. Only talking out loud tells them apart.
Let’s do one question together
Rather than talk about this in the abstract, here’s a real one. It came up in a lesson last week, and it’s the kind of question that separates the students who reason from the students who guess. Follow it through and you’ll see exactly what I mean.
The student in this lesson we’ll call Theo. That’s not his name, and a couple of details are blurred on purpose, but the question and the guess happened just like this.
The question. A wire in a circuit gets stretched, so it becomes longer and thinner. Which of these is true? The ammeter reading goes up. The total resistance stays the same. The resistance of the wire drops. The voltmeter reading falls.
What Theo did
He started well. He knew resistance depends on the length of the wire. Longer wire, more resistance. So the option saying total resistance stays the same had to be wrong, and he crossed it out. Good.
Then he slowed down, looked at the rest, and said it: “I’m guessing it’d be B.” Not “it’s B because”. Just “I’m guessing”. He’d told his tutor exactly what was happening and didn’t notice he’d said it.
What his tutor said next
“You’re making a couple of assumptions.”
Hugh, A Level Physics tutor
Not “no, it’s C”. Not the answer at all. Just: say the thinking out loud, and let’s both hear where it breaks.
Where it broke
The tutor asked him one thing. Is length the only quantity that changed?
It wasn’t. The wire got longer and thinner. Thinner means a smaller cross-sectional area, and area sits right there in the same equation as length. He’d spotted one change, acted on it, and treated the other as if it were standing still. Nobody had told him he was assuming anything. He didn’t know he was doing it.
Once he saw it, the question took him about forty seconds. Both changes push resistance the same way, so the resistance climbs, and the rest follows. He’d known all the physics. He just hadn’t checked the thing he’d decided not to look at.
Why this is the whole problem in miniature
If he’d guessed B and got it wrong, you’d see a lost point on a paper and think: he doesn’t know resistivity. So you’d buy him a revision guide on resistivity, and it wouldn’t help, because he knows resistivity perfectly well.
And here’s the darker version. If he’d guessed B and got it right, nobody would have noticed anything at all. He’d have carried the same habit into the exam, where it would cost him roughly one question in five for two years.
That’s why an A Level Physics tutor makes your child talk. A marked paper tells you what they got wrong. It can’t tell you what they got right by accident, and that number is usually bigger than parents expect.
Three things this changes in how we teach
Your child says it before they write it. Every question, out loud, first. It’s slower for about three weeks and then it isn’t, because guessing stops being easier than thinking.
We check the algebra, not just the physics. Ask a student to explain resistivity and they’ll manage. Ask them to rearrange the equation and half of them stall. When that happens, we stop teaching physics for twenty minutes and teach rearranging, because the physics was never the problem. This starts earlier than sixth form, which is why we go after it at GCSE too, in our guide to smarter GCSE Physics revision.
We make them justify the right answers. This is the one students hate. But a correct answer with no reasoning behind it is a coin toss you happened to win, and we’d rather find that out in October than in June. If June is already close, our piece on revising in the final month is the place to start.
Try it yourself tonight
You don’t need to know any physics to do this. Pick a question your child got right and ask them to explain why. Not what the answer was. Why.
A student who reasoned it will tell you, and you’ll be able to follow it even if you haven’t touched physics since school. A student who guessed will repeat the answer, slightly louder, and get irritated with you. That irritation is the tell. It’s not rudeness. It’s the sound of someone who can’t retrace steps they never took.
One lesson. One question. Out loud.
That’s genuinely all it takes to find out whether your child is reasoning or guessing.
The tutors who teach this way
Not every physicist is good at this. Making a student defend an answer they’ve already got right takes patience, and it takes a tutor who isn’t in a hurry to look clever. These three are.
Liza
Liza read Maths and Philosophy at Yale, then did a master’s at the LSE as a Chevening Scholar. The philosophy half matters here. She won’t let an argument past her just because it arrived at the right answer.
Hugh
Hugh has a doctorate from Oxford, a First from Imperial, and over ten years of teaching behind him. He’s the one who says “you’re making a couple of assumptions” and then waits, so a student has to show the working they skipped rather than land on the right letter by luck.
Murray
Murray teaches Physics, Chemistry and Maths from GCSE upwards. He’s good with the fast, confident guessers, because he slows them down without making them feel caught out, and that’s a harder trick than it sounds.
Questions parents ask us
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Improve your child’s physics grade
MAKE THEM SAY IT OUT LOUD
In an hour you’ll know what your child understands and what they’ve been getting right by luck.
