Graphs & Charts
Science: KS3, topic 4.1.15
Graphs and Charts
We can draw graphs to make data easier to visualise. Graphs allow you to spot trends and patterns, and analyse your data.
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Types of graphs
- You should use line graphs when:
- Independent and dependent variables are continuous.
Bar charts
- You should use bar charts for:
- Categorical data
- Discrete data
Pie charts
- You should use pie charts for:
- Percentage data
Drawing a graph
- You should draw your graph with a pencil.
- You should also use a ruler.
- Label each axis.
- Include the units.
Graph scale and points
- Label the axis with an appropriate scale.
- The scale should cover as much of the graph as possible.
- Draw plot points with an x.
Lines of best fit
- A line of best fit can be a smooth curve.
- You don't always need a ruler to draw a line of best fit.
Drawing a line
- To draw a line of best fit:
- Look from the bottom left of the graph.
- Trace the data pattern from its starting point.
Proportional trends
- The trend in a graph may be proportional.
- If the independent and dependent variables show a proportional relationship, the trend is proportional.
Checking the relationship
- One way to check for a proportional relationship is:
- Double the independent variable.
- Check if the dependent variable also doubles.
Test yourself on Graphs & Charts
What should pie charts be used for?