🗺️ Geographical Investigations – Summary for Test
1. ✅ What is a Geographical Investigation?
A geographical investigation is a study where you collect, analyze, and present data about the
natural or human world.
💡 Examples:
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Studying a river’s flow
Measuring how land use changes in a town
Surveying public opinion about pollution
2. 🔍 Types of Data
Type of Data
Description
Example
Primary Data You collect it yourself River depth measurements
Secondary Data Collected by others Maps, government reports
Data by Format
Description
Example
Numbers / measurements 2.5 m deep, 12 people
Quantitative
Opinions / descriptions “It’s very polluted”
Qualitative
3. ️ Ways of Collecting Data
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Field sketches / photos
Surveys & questionnaires
Measurements (e.g. river depth, wind speed)
Observation / land-use mapping
Using instruments (see below 👇)
4. ️ Geographical Instruments and Their Uses
Instrument
Tape measure
Stopwatch
Use
Distance / river width
Time (e.g. river velocity)
Instrument
Use
Ruler/metre stick River or stream depth
Compass
Direction
Clinometer
Slope / gradient
Thermometer
Temperature
Anemometer
Wind speed
Float (e.g. orange) River velocity (surface)
pH meter
Water or soil acidity
GPS / phone
Location
5. 📊 Sampling Methods
Method
How it Works
Advantage
Every place/person has equal chance Unbiased
Random
Easy, covers whole area evenly
Systematic Every 10 metres / 5th person
Sample from each group (age/land use) Fair, all groups included
Stratified
Fixed number from each category
Balanced
Quota
Fast, but may be biased
Convenience Whoever is easiest to reach
6. 🌊 Measuring Stream/River Depth
Steps:
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Use a tape measure to measure the stream width.
Place a ruler or metre stick vertically at regular intervals (e.g. every 0.5 m).
Record the depth from the surface to the bed.
Plot results on a cross-sectional graph.
7. 💨 Measuring River Velocity (Speed)
Float Method:
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Mark a 10 m stretch of river with poles.
Drop a float (like an orange) at the start.
Use a stopwatch to time how long it takes to float 10 m.
Use the formula: velocity = distance/time
🔁 Repeat 3–5 times and take an average.
8. ️ Measuring River Discharge
Formula:
Discharge=Cross-sectional Area×Velocity
Steps:
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Measure width and depths across the river.
Calculate cross-sectional area (width × average depth).
Measure velocity using the float method.
Multiply:
Discharge=Area (m2)×Velocity (m/s)⇒Answer in m3