Key facts

• Put the independent variable in the first column of a table and on the x-axis of a graph.
• Table headings include the quantity and its unit, for example Time (s). Units go in the heading, not in each cell.
• Categoric independent variable: bar chart. Continuous: line graph or scatter graph.
• Choose a scale that uses at least half of the grid and is easy to read (steps of 1, 2, 5 or 10).
• Draw a line of best fit (a smooth curve or straight line) with points evenly spread either side. Ignore anomalies.
• A straight line through the origin shows that two variables are directly proportional.

How to do it

1. Decide which variable goes on each axis.
2. Choose sensible scales and label both axes with units.
3. Plot each point carefully as a small cross.
4. Draw a single line of best fit.