weather

Cards (10)

  • Rain Gauge
    • Has a fixed diameter so that they collect the same amount of water
    • Comparisons can be made
  • Rain Gauge
    1. Funnel (A) to collect the water
    2. Container to collect water, which may be graduated
    3. Emptied once every 24hrs
  • Rain measurement

    Measured in millimetres
  • Rain Gauge

    • Sunk into the ground, but not level, so splashes or surface water can't get in
  • Anemometer
    • Three light rotating cups (mounted on a high pole) are blown around by the wind
    • The revolutions are counted & converted into m/s, km/h or knots
  • Sunshine Recorder (Heliograph)

    • Burns a timeline
    • Trace sunshine not the hours of daylight
    • The glass ball focuses the light
    • This burns a line onto the card
  • Max-min thermometer

    • Max thermometer contains mercury & min contains alcohol
    • As temp. rises, mercury expands & pushes up a metal index, and when it cools, mercury contracts, and the index is left in place at highest temp
    • As temp. falls, alcohol contracts & pulls metal index with it; but as alcohol expands, it flows past index, leaving it at its lowest temp
    • Both indexes read from the bottom once every 24hrs
  • Wet & dry bulb thermometer (hygrometer)

    • A dry bulb is a normal mercury thermometer, and it measures actual air temperature
    • The wet bulb is the same but is covered with a fine cloth connected to a water reservoir
    • Water evaporates from the cloth & cools temperature so it reads a few degrees lower than air temp
    • Both wet & dry bulb temperatures read
  • Barometer

    • An aneroid barometer has a vacuum chamber
    • As air pressure rises & falls, the chamber contracts & expands
    • Levers conduct this movement to a spindle, which moves the pointer on the dial, which records the air pressure in mmHg
  • Wind Vane

    • The wind blows the fletching so that the arrowhead points into the wind
    • Mounted on high places (rooftops)
    • Make sure no trees are blocking