How to Draw Scientific Graphs Correctly in Physics Practical Assessments
Paul explains about how to draw scientific graphs correctly in Physics practical assessments
What are Scientific Graphs?
Scientific Graphs are
- a way of exploring the relationship in data between two variables
- a way of analysing and presenting data, marking it easier to show patterns, trends and relationships
Straight linear line graphs can also be used to compare changes over the same period of time for more than one group. Pie charts are best to use when you are trying to compare parts of a whole. They do not show changes over time. Bar graphs are used to compare things between different groups or to track changes over time.
Creating a Table
The independent variable should place in the left hand column and the dependent variable on the right.
Drawing Scientific Graphs
- Give your graph a descriptive title. Something like “The relationship between A (independent variable) and B (dependent variable).”
- Ensure you have put your graph the right way around. The horizontal axis is your independent variable and the vertical (left hand) is your dependent variable.
- Determine the variable range
- Determine the scale factor of the graph.
- Label the horizontal and vertical axes with units clearly.
- Remove any outliers. Point any anomalous results, as any outliers that do not fit your trend and label them in your key/legend. This will net you extra points for seconds extra work.
- Draw a line of best fit. Make straight line graphs as they tell you how one thing changes under the influence of some other variable.
- Never connect the dots on your line graph. Most graphs of experimental data in Physics are linear.
Bad Scientific Graphs
At least half the marks for any graph question are awarded for presenting your graph according to standard conventions; this is before the actual content has even been assessed. Before moving on from any graph question or from a graph section of your coursework, ensure you have followed the 6 Graph Commandments
- No Titles
- No Labels on the horizontal and vertical axes.
- No units
- Connected the Dots
- Having Outliers
- Incorrect Scale (In this example below, the vertical axis does not start from zero.)
Good Scientific Graphs
- Descriptive Titles
- Clear Labels on the horizontal and vertical axes.
- Clear units
- Straight Linear Line Graph
- Removing Outliers
- Correct Scale