TL;DR:
Only do this if your teacher allows it, and follow their size and content rules exactly.
Put on the card only what you forget under pressure, organized by problem type, not everything you know.
Writing the card yourself is the study. The card itself is the by-product.
Some teachers allow a single index card or a sheet of notes in an exam. If yours does, the card is a gift, but a badly made one is useless: a wall of tiny text you cannot read under time pressure. A good card is short and organized, and the real value comes from making it.
Watch out: Follow your teacher's rules exactly: the size, one side or both, handwritten or not, and what may be on it. If you are not sure whether something is allowed, ask before the exam.
Why making the card is the study
To decide what goes on a small card you have to sort what you know from what you forget. That sorting is a high-quality review. Copying someone else's card skips it and gives you a list you do not trust. Write your own.
What to put on it
Formulas you cannot reliably recall, not the ones you know cold.
Conditions for using them, such as constant acceleration.
Sign conventions and unit reminders.
A short list of your own common mistakes.
A tiny example for any formula you often misuse.
The steps
List everything that might go on it: From your notes, past tests and homework, write every formula and rule.
Cross off what you know: Test yourself. If you can write it from memory, it does not need the card.
Group by problem type: Sort the rest by the kind of problem it solves, not by chapter.
Draft, then shrink: Write it on scrap paper to see the space. Cut until it fits readably.
Practise using it: Do a timed practice problem set with only the card for help.
Worked example: one index card for a physics final
Say the final covers motion, forces, energy and circular motion. After testing yourself, you know the basic definitions but reliably forget these. Here is the card, grouped by problem type.
Problem type | On the card |
|---|---|
Constant acceleration |
|
Forces |
|
Energy |
|
Circular motion |
|
My mistakes | Square v. Convert km/h to m/s by dividing by 3.6. Check units at the end. |
Now use it. A car moving at 20 m/s brakes with a constant deceleration of 5.0 m/s². How far does it travel before stopping? The row says constant acceleration, and the third formula has no time in it: v² = v₀² + 2aΔx.
0 = 20² + 2 × (−5.0) × Δx = 400 − 10Δx.10Δx = 400, soΔx = 40 m.Check with time:
t = 20 / 5.0 = 4.0 s, andΔx = 20 × 4.0 − ½ × 5.0 × 4.0² = 80 − 40 = 40 m. It matches.
The card did its job: it pointed to the right formula and reminded you about the sign. It did not solve the problem. You did, because you had practised.
How to know the card is ready
Cover the card and write its contents from memory. Whatever you can write cold, cross off the card, because it is taking up room. Whatever you cannot, circle: that is what the card exists for, and what you should keep practising. After two rounds you may find that the card is half empty and that you no longer need it for most of the things on it.
Then do a timed set of problems with the card beside you. If you look at it more than a few times per problem, reorganise it: the layout is slowing you down.
Layout tips
Use headings in a different colour or underline them.
Leave white space. A dense card is hard to scan.
Keep your handwriting legible. If you cannot read it in a hurry, it is wasted.
Put the most-forgotten items near the top.
Handwriting and size
A standard index card is small, around 3 by 5 inches, so if your handwriting is large you will not fit much. Write small but neat, with a fine pen, and leave a line between groups. Use abbreviations you will understand under stress, and write units clearly. If your teacher allows both sides, keep the front for formulas and the back for your mistakes list and a couple of reminders.
Mistakes to avoid
Using someone else's card.
Filling every millimetre with tiny text.
Putting on the card things you know well, and leaving out what you forget.
Never practising with the card, so you do not know where things are.
Relying on the card instead of learning the material.
Your plan for this week
Confirm the rules for the card with your teacher.
Test yourself and list what you forget.
Draft the card on scrap paper, then copy it.
Do a timed set of problems using only the card.
Frequently asked questions
What if my teacher does not allow a card?
Make one anyway as a study tool and then do not take it in. You will find you remember most of it.
Should I put worked examples on it?
One tiny example for a formula you often misuse can help. Full worked examples take up too much space.
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