WEATHER - INSTRUMENTS

Weather Instruments

 THERMOMETER measures the air temperature. Most thermometers are closed glass tubes containing liquids such as alcohol or mercury. When air around the tube heats the liquid, the liquid expands and moves up the tube. A scale then shows what the actual temperature is. When reading a thermometer note the increments of measure as well as which Units of measure are being used - Fahrenheit - F*  or  Celsius - C*.
Freezing point of water = 32* F  or  0* C
Boiling point of water = 212* F  or  100* C

 BAROMETER

measures air pressure. It tells you whether or not the pressure is rising or falling. A rising barometer means sunny and dry conditions, while a falling barometer means stormy and wet conditions. An Italian scientist named Torricelli built the first barometer in 1643.   Units of measure millibars (mb) or inches of mercury.  There are 2 needles - both which can be moved to help read the pressure.
Long needle shows the current air pressure
Short needle shows the previous air pressure

If pressure has risen, skies will be getting clearer.
If pressure has fallen, skies will be getting cloudier




SLING PSYCHROMETER measures relative humidity, using the cooling effect of evaporation. Two thermometers are used in a sling psychrometer. Wet the cloth of one of the thermometers and swing the psychrometer around a few times. Water evaporates from the cloth, causing the temperatures on that thermometer to be lower the the other (cooling it down).  Temperatures of the two thermometers are converted into a percentage using a relative humidity table.
measures - relative humidity (%) or measures dew point (C*, F*)



RAIN GAUGE measures the amount of rain that has fallen over a specific time period.  Make sure they are not under trees or overhang to distort the amount of precipitation that has fallen.  Measure units = inches or centimeters.

WIND or WEATHER VANE is an instrument that determines the direction from which the wind is blowing.
The arrow points where the wind is blowing from.
Wind direction is described by the direction it blows from.  Units of measure is recorded in a compass direction of N, S, W, E.
This example the wind is blowing from the Northwest.

ANEMOMETER measures wind speed. The cups catch the wind, turning a dial attached to the instrument. The dial shows the wind speed. Units of measure are miles/hour or knots/hour

A WIND SOCK is a conical textile tube(which resembles a giant sock, hence its name) designed to indicate wind direction and relative wind speed. Windsocks typically are used at airports & at chemical plants where there is risk of gaseous leakage.  Unit of measure = miles/hour or knots/hour









WEATHER MAPS indicate atmospheric conditions above a large portion of the Earth's surface. Meteorologists use weather maps to forecast the weather. 



HYGROMETER measures the water vapor content of air or the humidity.

WEATHER BALLOON measures weather conditions higher up in the atmosphere. 

COMPASS is a navigational instrument for finding directions. 

WEATHER SATELLITES are used to photograph and track large-scale air movements. Then meteorologists compile and analyze the data with the help of computers. 








YOUR EYES are one of the the best ways to help detect the weather. Always keep an eye at the sky and you'll usually be on top of weather conditions.










PSYCHROMETER




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