Choose and construct scientific representations

Students choose and construct tables, graphs, models and mathematical relationships; label them correctly; process data without losing raw values; and explain what a representation shows and what it leaves out.

• Raw table: exact observations and measurements.
• Column graph: compare categories.
• Line graph: ordered continuous change such as temperature over time.
• Scatter plot: relationship between paired numerical variables.
• Food web: feeding/energy-transfer relationships.
• Dichotomous key: identification by paired choices.
• Timeline: sequence through time.
• Equation/rule: quantified relationship.

Dataset: temperature measured every minute for 10 minutes.

Model: use a line graph because time is ordered and continuous; time goes on x-axis and temperature on y-axis. Include title, units and an even scale.

Descriptive title; quantity + unit labels; independent variable first/x-axis; dependent variable y-axis; even non-misleading scale; accurate plotting; legend where needed; conventions explained for models.

Changing a scale changes visual emphasis, not the underlying data. A spreadsheet-generated chart is not automatically valid.

Useful processing includes sorting/filtering, unit conversion, totals, means, ranges and applying a simple mathematical rule. Keep the original raw data so processing can be checked.

A model deliberately selects relevant features and omits others. Food webs, particle diagrams and Earth–Moon–Sun models are useful because they simplify. They are not exact copies of reality.

We do: repair a graph with missing units, uneven scale and variables on unsuitable axes.

You do: choose a representation for (a) species counts at four sites and (b) plant height versus light intensity; justify each.

Exit ticket: “Any graph type works if the data are correct.” Evaluate this claim.