11.2 Graphical techniques
Essential idea:
Graphs are a visual representation of trends in data.
Understandings:
- Graphical techniques are an effective means of communicating the effect of an independent variable on a dependent variable, and can lead to determination of physical quantities.
- Sketched graphs have labelled but unscaled axes, and are used to show qualitative trends, such as variables that are proportional or inversely proportional.
- Drawn graphs have labelled and scaled axes, and are used in quantitative measurements.
Applications and Skills:
- Drawing graphs of experimental results including the correct choice of axes and scale.
- Interpretation of graphs in terms of the relationships of dependent and independent variables.
- Production and interpretation of best-fit lines or curves through data points, including an assessment of when it can and cannot be considered as a linear function.
- Calculation of quantities from graphs by measuring slope (gradient) and intercept, including appropriate units.