Line Graphs are the standard method for representing river channel cross-sections, where the x-axis shows the distance across the channel and the y-axis represents the depth at each point.
Bar Graphs are most effective for comparing discrete data sets across different locations, such as comparing the average sediment size at an upstream site versus a downstream site.
Scattergraphs are used to identify relationships or correlations between two continuous variables, such as the relationship between river discharge and channel width.
Annotated Photographs and field sketches provide a visual record of landforms (e.g., meanders or waterfalls) and the specific conditions under which data was collected.
| Feature | Primary Data | Secondary Data |
|---|---|---|
| Source | Collected by the student in the field | Existing records from agencies/maps |
| Purpose | Specific to the enquiry hypothesis | Provides context, history, or scale |
| Examples | Velocity, width, pebble size | OS maps, Met Office rainfall data |
| Limitations | Time-consuming, prone to human error | May be outdated or not site-specific |
Reliability vs. Validity: Reliability refers to whether the study can be repeated to achieve the same results, whereas validity refers to whether the methods used actually measure what they were intended to measure.
Anomalies vs. Trends: A trend is a general pattern in the data (e.g., depth increases downstream), while an anomaly is a single data point that deviates significantly from that pattern.
Graph Completion: When asked to complete a graph, always use a ruler for bar charts and ensure the width of new bars matches existing ones to maintain consistency.
Calculating the Mean: Always show your full working () to secure marks even if a calculation error occurs; pay close attention to rounding instructions (e.g., one decimal place).
Identifying Anomalies: Look for points that sit far from the line of best fit or break a sequence; in exams, you are often required to suggest a geographical or human reason for these outliers.
Evaluation Questions: For 8-mark questions, structure your answer by discussing what went well, what limitations existed (equipment or design), and how you would improve the study next time.
Ignoring Anomalies: Students often try to force a line of best fit through an anomaly; instead, the anomaly should be acknowledged and explained (e.g., the float got stuck on a rock).
Rounding Errors: A common mistake is rounding too early in a multi-step calculation or failing to round up when the next digit is 5 or higher.
Confusing Primary and Secondary: Ensure you can distinguish between data you measured yourself and data you looked up online or in a book.
Vague Evaluations: Avoid saying "the equipment was bad"; instead, specify that "the flow meter was obstructed by weeds, leading to an underestimation of velocity."
