Weather Instruments

A 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.
barometer

A 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 than the other.
sling-psychrometer

A RAIN GAUGE measures the amount of rain that has fallen over a specific time period.
rain-gauge

A WIND VANE is an instrument that determines the direction from which the wind is blowing.
wind-vane

An ANEMOMETER measures wind speed. The cups catch the wind, turning a dial attached to the instrument. The dial shows the wind speed.
anemometer

A WIND SOCK is a conical textile tube, which resembles a giant sock, designed to indicate wind direction and relative wind speed.
wind-sock

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

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

A WEATHER BALLOON measures weather conditions higher up in the atmosphere.
weather-balloon

A COMPASS is a navigational instrument for finding directions.
compass

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

YOUR EYES are one of 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.