When one science gets almost all your revision, the others fall behind without anyone noticing, including you. The repair is to measure the balance using your own marked work, then move time toward the gaps.
This is not about liking every science equally. It is about making sure that a strength in one section does not hide a weakness in another, since Combined Science papers can move between all three.
What does it look like?
- You revise the same science most evenings.
- Your notes for one science are neat and the others are thin.
- You skip mixed questions when they start with an unfamiliar model.
- Your marks are uneven across the three sciences, and you explain it as “that one is just hard”.
What might be causing it?
There are a few academic reasons. One science may rely on a skill that is shaky, such as rearranging a formula or reading a graph.
Early confusion in a topic can also leave later topics feeling impossible. And comfort is rewarding: a science you already understand gives quick wins.
A worked example
A student has ten hours of revision a month. Across recent mixed sets they attempted 18 questions per science, and they count the correct answers.
| Science | Correct (out of 18) | Missed | Hours spent this month |
|---|---|---|---|
| Biology | 14 | 4 | 6 |
| Chemistry | 9 | 9 | 3 |
| Physics | 7 | 11 | 1 |
Total missed: 4 + 9 + 11 = 24.
Step 1: Find each share of the gaps. Biology 4/24 ≈ 17%, Chemistry 9/24 ≈ 38%, Physics 11/24 ≈ 46%.
Step 2: Share out the ten hours. Biology 1.7, Chemistry 3.75, Physics 4.6.
Step 3: Round to useful blocks. Biology 2, Chemistry 4, Physics 4, which adds up to 10.
Step 4: Compare with what happened. Biology had 6 hours but only 4 missed questions, and Physics had 1 hour with 11 missed. The effort had gone to the science that needed it least.
Step 5: Plan the first Physics sessions small. Pick the two topics with the most misses and start with one short, worked question each.
The numbers are invented for illustration, so use your own marked work.
Practical steps
- Sort your last few mixed sets by science and count the misses.
- Build the split from those counts, with a floor of one block for every science.
- Put the weakest science first in the session, while your attention is fresh.
- Re-check after two weeks. The balance audit lesson and the lesson on avoiding one strength to ignore another section walk through this.
- Use the realistic revision planner to keep the plan inside the hours you really have, and the mixed original practice for unlabelled questions.
- Use the scientific investigation critic on a short investigation in the weak science to practise reasoning from evidence.
If the confusion is about what belongs in the course, see the page on studying unnecessary extension.
When might a teacher help?
Self-study is enough when a two-week audit shows the balance moving.
Online one-to-one tuition is worth considering when you keep avoiding the same science, or cannot tell if the problem is a missing skill or a missing topic. A teacher can work through the first steps with you in the weak science. The Combined Science tuition page explains the paid one-hour trial with an assigned teacher.