IGCSE weather and instruments

Rain gauge

A device for collecting and measuring the amount of precipitation which falls.

Wind rose

A diagram showing the relative frequency of wind directions at a place.

Prevailing wind

Direction wind comes from is call the......

Anemometer

Instrument used to measure wind speed.

six's thermometer

Records the maximum and minimum temperatures reached over a period of time, for example 24 hours.

Wind vane

Shows the direction the wind is blowing.

relative humidity

The amount of water vapour present in air expressed as a percentage of the amount needed for saturation at the same temperature.

Climate

The average daily weather for an extended period of time at a certain location.

Weather

The day to day state of the atmosphere.

Troposphere

The lower part of the earths atmosphere.

Millibars

Unit for air pressure.

Stevenson screen

A shelter or an enclosure to shield meteorological (weather) instruments against precipitation and direct heat radiation from outside sources, while still allowing air to circulate freely around them. It forms part of a standard weather station.

Oktas

A unit used in expressing the extent of cloud cover, equal to one eighth of the sky.

Trace

A very small amount of precipitation (too small to be measured), recorded as a ....

Barometer

An instrument measuring air pressure.

Hygrometer

An instrument used to measure humidity.