Pearson Edexcel International GCSE Science Single Award Practical Skills 5: Tables, graphs and calculations

Pearson 4SS0 expects students to record observations methodically, process results, draw and interpret graphs, perform calculations and communicate evidence. These skills can appear in Biology, Chemistry or Physics contexts. The representation must suit the question, preserve raw evidence and make uncertainty visible.

Build an evidence-preserving table

Put the independent variable in the first column and the dependent measurements in later columns. Write each heading as quantity followed by unit, such as time / s or gas volume / cm³. Do not repeat the unit in every cell. Keep raw repeats separate before calculating a mean so variation and anomalies can be inspected.

Use consistent decimal places within a measured column when the same instrument was used. A digital display of 12.4, 13.1 and 14.0 should not become 12.4, 13.1 and 14, because the final zero communicates resolution. Calculated values should not claim more precision than the measurements support.

Qualitative observations need structure too. A food-test table might include sample, initial appearance, reagent and final observation. “Positive” alone discards the colour evidence. A refraction table should distinguish angle of incidence from angle of refraction and state degrees in the headings.

Choose the right graph

Use a scatter or line graph when both variables are continuous, such as gas volume against time or current against voltage. Plot the independent variable horizontally and the dependent variable vertically unless a specific convention applies. Use a bar chart for discrete categories, such as mean gas volume for different sugar types. Bars should be separated because the categories do not form a continuous scale.

Choose linear, evenly spaced scales that use most of the available plotting area. Label both axes with quantity and unit. Plot points accurately using small crosses or dots. A best-fit line or smooth curve should represent the overall pattern rather than connect every point in sequence. Do not force a line through the origin unless theory and the evidence justify it.

An anomalous point lies away from the overall pattern, but it should not be erased automatically. Check transcription, apparatus events and repeat values. Display it, discuss it and exclude it from a calculation only with a reason.

Gradients and intercepts

For a straight best-fit line, select two well-separated points on the line, not necessarily original data points:

$$\text{gradient} = \frac{\text{change in vertical quantity}}{\text{change in horizontal quantity}}$$