Set up the axes correctly
Graph marks start before you plot a single point:
- Label each axis with the quantity and its unit, for example time / s.
- Choose a uniform scale that spreads the points across most of the grid; awkward scales like three squares per unit lose marks and cause plotting errors.
- Follow the convention of manipulated variable on the x-axis and responding variable on the y-axis unless told otherwise.
Plot points and draw the line
Plot every point accurately with a small cross or dot, and check any point that looks out of line. Draw a single thin best-fit line or smooth curve that balances the points; do not connect them dot-to-dot, and do not force the line through the origin unless the physics requires it.
Use the graph, do not just draw it
Most questions then ask you to read information from the graph:
- For a gradient, draw a large triangle, read both coordinates with units, and show the division.
- For an intercept, read it where the line crosses the axis and state its unit.
- Relate the gradient or intercept back to the physics quantity the experiment is measuring.
Common ways students lose graph marks
Missing units on axes, cramped scales, sloppy plotting, thick lines, and finding a gradient from a small triangle are the usual culprits. Writing the final value without showing the read-off also costs method marks.
Graph skills improve with repetition. Plot graphs from past Paper 3 data every week and check your axes, scale and gradient working against the marking points. If the same errors keep appearing, a short one-to-one review of your graphs can correct habits that are hard to spot yourself.