1. Weather Instruments
IGCSE Geography

2. Temperature Max Min Thermometer Six’s Thermometer
Max-Mercury
Min-Alcohol
Measures shade temperature (Stevenson’s screen)
Read off at bottom of the index (reset with magnet)
Read at eye level
Measured in ºC

3. Humidity Wet/Dry Bulb thermometer Hygrometer Comparison tables
Wick and reservoir of water
Comparison tables
Calculate depression of wet bulb (Dry – Wet)
Read off table
Measures in shade (Stevenson’s screen)
Units = % Relative humidity

4. Wind Speed Anemometer Km per hour Cups or blades
Clear unobstructed location
Km per hour

5. Wind Direction
Wind Vane
Recorded on Wind Rose
Compass Directions

6. Air Pressure Aneoid Barometer Barograph Millibars
Plots changes in pressure
Millibars
Measured in shade (Stevenson’s screen)

7. Rainfall Rain gauge Siting factors Regular intervals (24hours)
Clear view of sky
Recessed into ground
Approx 30cm above ground
Grassy surface (avoid splash back)
Read off at eye level
Regular intervals (24hours)

8. Sunshine Sunshine recorder Glass ball focuses light
Burns a timeline
Traces sun shine not hours of daylight
Glass ball focuses light
Burns line onto card
Units = Hours

9. Stevenson’s Screen Houses temperature / humidity /pressure instruments
Features
Insulated roof
Painted white to reflect heat
Louvered (slatted) sides aid air circulation
Located m above ground

10. Cloud Cover Cloud Mirror Divide mirror into 16 equal squares
Lay mirror on ground with clear view of sky
Estimate cover
Units = Oktas