Geography Topic
Weather instruments
- Read notes
- Flashcards
- Quiz
- Confident
Study focus - 3 things
- Each weather element has a specific instrument — learn the matching pairs
- Know what each instrument measures, the unit it uses, and how the reading is taken
- Some instruments look or sound similar (barometer vs thermometer vs hygrometer) — practice the differences
Section 1Why we use weather instruments
Weather instruments let us turn the elements of weather into numbers we can record, compare, and forecast with. Without measurements, weather reports would just be guesses.
Section 2The core instruments
Thermometer — temperature (°C). Barometer — air pressure (mb or hPa). Hygrometer — humidity (%). Anemometer — wind speed (km/h or m/s). Wind vane — wind direction. Rain gauge — precipitation (mm). Sunshine recorder — hours of sunshine. Each is matched to one element of weather.
Section 3How some of them work
Thermometer: liquid (mercury or alcohol) expands as it warms and rises up a scale. Anemometer: cups spin in the wind; the spin rate gives the speed. Rain gauge: a cylinder collects rain over 24 hours; you read the depth in mm. Wind vane: an arrow free to swing — it points TO the direction the wind comes FROM. A Campbell-Stokes sunshine recorder uses a glass ball to focus sunlight onto a card, burning a line whenever the Sun is shining.
Section 4Recording the readings
Weather stations take readings at the same time each day (often 9 a.m.) so the data can be compared over time. Instruments are kept in a Stevenson screen — a white wooden box with louvred sides — which lets air flow through but blocks direct sunlight and rain, giving accurate readings.
Examples
You walk outside and want to know whether it will rain. Which TWO instruments would you check first, and why?
The barometer (air pressure) and hygrometer (humidity). Falling pressure plus rising humidity is a classic sign of approaching rain.
A wind vane points east. Which way is the wind blowing?
From the east. Wind vanes name the direction the wind comes FROM, not where it's going. So an east-pointing vane means an "easterly" wind — coming from the east, blowing toward the west.
Now let's water it
Session runs notes to flashcards to quiz back-to-back.