Reading a graph in science

Drawing and interpreting graphs, including gradients and lines of best fit.

What it is

Scientific graphs plot the independent variable on the x-axis and the dependent on the y, with a suitable scale, labelled axes with units, and a line or curve of best fit.

Where it applies

All three sciences, with dedicated marks for graph drawing.

How it works

A line of best fit follows the trend; it is not a dot-to-dot and does not have to pass through every point or the origin.

Gradient gives the rate and has units, which is what makes it meaningful — the gradient of a distance-time graph is speed in metres per second.

How to use it in your work

Label both axes WITH UNITS. It is a mark, every time.

Choose a scale that uses at least half the grid. Cramped graphs lose marks.

For a gradient, draw a large triangle and show the calculation on the graph.

Identify anomalies and exclude them from the line of best fit rather than bending the line towards them.

Where to get help

Your teacher and your board's specification. Bitesize for worked examples, and the subject song for the topic list.