Guide for parents · September 2026
Most KS3 science marks are lost on maths and writing
Most Key Stage 3 science marks are lost to maths, writing or variables rather than to science. How to tell which before paying a science tutor.
"Science tutor" is three jobs advertised as one
At Key Stage 3 science is usually timetabled as a single subject, and in many schools one teacher delivers all of it for a year. That teacher has a degree in one of biology, chemistry or physics, and is teaching the other two.
The same is true of tutors. Somebody advertising Key Stage 3 science is a specialist in at most one third of it. Before hiring one, it is worth knowing which third your child is actually struggling with — and, more often than parents expect, the answer is none of them.
Where Key Stage 3 marks are really lost
| What went wrong on the paper | The underlying skill |
|---|---|
| "Describe the pattern in the results" | Reading a trend rather than listing values |
| Rearranging a formula in physics | Algebra, specifically inverse operations |
| Units, prefixes and conversions | Place value and multiplying by powers of ten |
| Calculating a mean from a results table | Division, and knowing what to exclude |
| Explaining why an experiment was unfair | Separating the variables |
| A long biology answer that scores two of five | Writing structure, not knowledge |
Three of those six are maths. One is writing. One is the reasoning strand rather than content. Only one is science knowledge in the ordinary sense.
This is the argument that a science page can make and a maths page cannot: the cheapest way to raise a Key Stage 3 science mark is very often to stop treating it as a science problem.
Working scientifically is the part nobody practises
Alongside the content, the science curriculum in England carries a strand about how science is done — deciding what to change and what to hold constant, taking readings, identifying anomalies, and drawing a conclusion the data actually supports. It is assessed throughout, and it is the part children get least practice at outside a lab.
The fair test is the standard example. A child who has not firmly grasped that only one thing may change will design an investigation that cannot answer its own question, then write a confident conclusion from data that does not support it. No amount of revising the content fixes that, because the content was never the problem.
At home the whole of that skill fits into three questions. What are you changing. What are you measuring. What are you keeping the same. If your child can answer all three about their own experiment, the design is sound.
Sorting the maths out first
If you suspect the maths, you can check it rather than guess. Pobbi's maths learning check is twenty questions drawn from a bank of eighteen skills, aimed at Year 5 to Year 9. About twelve minutes, free, no card.
For a science parent the relevant items are specific: place value, multiplication and division, negative numbers, converting between fractions, decimals and percentages, and the early algebra — simplifying an expression, substituting a value, solving a two-step equation. Those five things are what a physics or chemistry question is quietly asking for while appearing to ask about science.
When one fails, the check works downwards. A failed equation triggers checks on simplifying and substitution. A failed conversion triggers checks on turning a fraction into a decimal and on finding a percentage of an amount. Each skill comes back secure at eighty per cent or above, still being practised between fifty and seventy-nine, or still being learned below fifty.
If the algebra comes back insecure, you have your answer and a science tutor would have spent the hour teaching maths.
What no home tool replaces
Practical work. Equipment, apparatus, a Bunsen burner, the experience of taking a reading that disagrees with what you expected and having to decide what to do about it. That belongs to school, and any product claiming to substitute for it is overselling.
Pobbi's science coverage is narrower than its maths coverage and it would not help anyone to imply otherwise. It holds no exam board specification and makes no claim to cover any nation's curriculum in full. In England the national curriculum is the common reference for maintained schools while academies organise it themselves, and Scotland, Wales and Northern Ireland follow their own.
A science tutor is the right purchase when the content itself is genuinely the gap — when the maths is secure, the variables are understood, and your child simply does not know the biology. It is also the right purchase when a specific specialism is needed, in which case ask which of the three sciences the tutor actually studied.
Questions from Key Stage 3 science parents
My child enjoys science but the marks are poor.
Enjoyment and marks measure different things. Take a returned paper and sort the lost marks into knowledge, maths and expression before deciding anything.
Physics looks like the weak one. Physics tutor?
Check the algebra first. If rearranging a simple formula is shaky, fixing that usually fixes the physics without a physics tutor.
Is learning definitions worth the effort?
Some of it is unavoidable, but a definition recalled without meaning gets used in the wrong place. Ask for an example instead of the definition — a child who can give one has understood it.
Should we do practicals at home?
Some, for interest, but the point is the reasoning rather than the equipment. Talking through what would make an investigation fair is closer to what the marks reward.