Class 8 Science tuition: one mark hiding three subjects

Because each strand is marked on a different skill. Physics wants numericals with units, chemistry wants equations and properties, biology wants labelled diagrams and processes - and a single mark averages all three into something that tells you very little.

This is the practical thing to understand about the year, and it explains a pattern most parents notice without being able to name.

• Physics is where numericals begin in earnest - pressure, force, and the habit of writing units on every line.
• Chemistry starts using equations to describe a change rather than sentences, which is a genuinely new kind of writing.
• Biology is diagram-heavy, and diagrams are marked on labels rather than on draughtsmanship.

Seventy out of a hundred could be three strands at seventy or two at eighty-five and one at forty. In Class 9 the three separate and the answer arrives on its own - a year later than it was useful.

Look at the paper rather than the mark. Add up where the marks were lost by chapter - physics, chemistry or biology - and the pattern is usually visible within two papers.

This takes ten minutes with a returned paper and is worth more than any amount of general revision.

Go through the question paper and mark each question P, C or B. Then add up the marks lost in each. Two things usually show up at once: which strand is losing marks, and whether they are being lost on content or on presentation - a numerical without units and a diagram without labels are both full understanding scoring half.

Ask your child directly as well. 'Which of the three would you least like a test in tomorrow?' A twelve-year-old will tell you accurately, and it takes one sentence.

Because working and units are marked separately from the answer. A correct number with no unit, or with the substitution done mentally, scores a fraction of what the same understanding would score written out.

Class 8 is where a child meets a subject that gives independent marks for how a numerical is set out. Three habits secure them and all three are mechanical:

• Write the formula first, before substituting anything.
• Carry the units through every line, not just onto the final answer.
• State the answer as a sentence when the question asked one.

These are worth establishing now precisely because Class 9 and 10 Physics assume them. A child who has written numericals this way for two years does not have to learn it in a board year.

By assessing the three strands separately in the first session and teaching to whichever is weakest, rather than covering the book evenly. A combined mark cannot tell you where the term should go; three separate checks can.

Most Class 8 Science tuition works through the chapters in order. That is reasonable and it spends equal time on a strand that is fine and one that is not.

We start with three short checks instead - a numerical, a displacement reaction, a labelled cell diagram. Fifteen minutes, and the term plans itself. Where all three are healthy we teach ahead of the school; where one is not, that one gets the weight until it catches up.

On adolescence: we teach it as the biology chapter it is, plainly and without embarrassment. It is examined like any other chapter and a child hurried past it is being set up to lose marks on something they were never actually taught.

See Class 8 tuition, Science tuition Class 6 to 10, our free Class 8 Science worksheets, and fees published by class. The free assessment is 20 minutes.