IGCSE Physics: Why Your Child Knows the Formulas but Still Loses Marks

Knowing the formula sheet is useful, but IGCSE Physics formulas do not solve questions by themselves. Students still have to select the correct relationship, interpret the situation, convert units and present a sensible answer.

That is why a child can recite equations perfectly and continue losing calculation marks.

The difficult step happens before substitution

Many students scan the numbers, choose an equation containing similar symbols and type immediately into the calculator. This fails when the question requires an intermediate value or combines two ideas.

Before calculating, your child should state:

• what quantity is required
• what information is known
• which physical principle connects them
• whether any units must be converted

Symbols can hide weak understanding

Students sometimes confuse mass and weight, energy and power, or current and charge because the equation has been memorised without meaning.

Ask them to explain every quantity in words and predict what should happen when one quantity increases. If that reasoning is insecure, revisit the concept.

Working must remain visible

A reliable structure is:

1. write the relationship
2. convert units
3. rearrange if necessary
4. substitute values
5. calculate and include the unit
6. check whether the result is realistic

Clear working reduces calculator errors and can preserve method marks when the final number is wrong.

Practise choosing, not merely using, equations

Complete short mixed sets where the relevant equation is not announced. Then mark errors by cause: selection, rearrangement, conversion, arithmetic or interpretation.

Students following Cambridge should practise against the expectations in the official IGCSE Physics 0625 resources.

If the student is mathematically strong but still makes errors, read why good Maths students get IGCSE Physics calculations wrong.

At OTA Learning Studio, we teach the reasoning around equations—not just the formula itself. Book a free consultation if formula knowledge is not turning into IGCSE Physics marks.