Measuring Elements Of The Weather Flashcards
Define the term weather.
The day to day changes in the conditions of our atmosphere - the weather elements.
Define the term climate.
The average conditions of weather, usually based over a period of about 35 years.
Temperature is measured using a…
maximum-minimum thermometer
A maximum-minimum thermometer has two sides, one for…
hottest and one for coldest temperatures
To find the temperature using a maximum-minimum thermometer, read…
the bottom of each marker and then use a magnet to reset the markers
Precipitation is measured using a …
rain gauge
To record precipitation using a rain gauge, read off the…
level of the water in the measuring cylinder at the same time each day
The measuring cylinder of the rain gauge should be emptied and repositioned…
in an open area every 24 hours
Wind direction is measured using a…
wind vane
The arrow on a wind vane points to the direction where…
the wind is coming from
The units for wind direction are the…
eight compass points
Wind speed is measured in…
knots
Wind speed is measured using an…
anemometer
An anemometer has small cups which…
spin around as they catch the wind, creating a digital readout which tells you the current wind speed
Air pressure is measured in…
millibars (mb)
Air pressure is measured using a…
barometer
To find the air pressure, read the…
needle on the barometer
A barometer may have a …. , which shows…
second needle, what the pressure was at a certain time
If a barometer has a second needle, the main needle shows…
how the pressure has changed
Air pressure can also be measured using a…
mercury barometer
A mercury barometer is a…
3 feet tall glass tube that sits upside down in a mercury reservoir
The mercury barometer works by…
balancing the weight of the mercury in the glass tube against atmospheric pressure
If the weight of the mercury in the glass tube is lighter than the atmospheric pressure, …. and vice versa
the mercury level in the glass tube rises
Cloud cover is measured in…
oktas (eighths)
Cloud cover is measured by experts who…
estimate how many eighths of the sky are covered with cloud
To measure air temperature, thermometers are placed in a…
Stevenson Screen
A Stevenson Screen is designed so that only…
air flowing through the box is recorded
A Stevenson Screen is painted white to…
reflect heat energy
The shade inside a Stevenson Screen ensures that…
direct sunlight cannot give a false reading
Rain gauges must be placed in an…
open area
Rain gauges must be ……. to the ground, so that they don’t get….
anchored securely, blown over by the wind
The top section of a rain gauge where the water is collected needs to be…
more than 30 cm above the ground to avoid rain splash when the ground is saturated
Wind vanes should be placed…
on a roof free from shelter (e.g. Church spire)
Anemometers should be placed…
high up to avoid shelter
The problem with anemometers is that they usually require…
more than 10 knots of air flow to ensure an accurate reading for wind speed
