Weather Factors
Weather refers to the state of the atmosphere at a specific time and place. Weather describes conditions such as air pressure, wind,temperature,and the amount ofmoisture in the air.
The Sun provides almost all of Earth’s energy. Energy from the Sun evaporates water into the atmosphere where it forms clouds. Eventually,the water falls back to Earth as rain or snow. However, the Sun does more than evaporate water. It is also a source of heat energy. Heat from the Sun is absorbed by the Earth's surface, which then heats the air above it. Learn more about Weather Factors
Air Temperature
Air is made of molecules that are always moving randomly, even when there's no wind. Temperature is a measure of the average amount of motion of molecules. When the temperature is high, molecules in air move rapidly and it feels warm. When the temperature is low, molecules in air move less rapidly, and it feels cold. More info on Air Temperature
A Barometer is a device used to measure atmospheric pressure. Because atmospheric pressure changes with distance above or below sea level, a barometer can also be used to measure altitude. In the mercury barometer, atmospheric pressure balances a column of mercury, the height of which can be precisely measured. Normal atmospheric pressure is about 14.7 lb per square inch, equivalent to 30 in. (760 mm) of mercury. Other liquids can be used in barometers, but mercury is the most common because of its great density. An aneroid barometer indicates pressure on a dial using a needle that is mechanically linked to a partially evacuated chamber, which responds to pressure changes. Learn more about a BarometerWind
Air moving in a specific direction is called wind. As the Sun warms the air, the air expands and becomes less dense. Warm, expanding air has low atmospheric pressure. Cooler air is denser and tends and tends to sink, bringing about high atmospheric pressure. Wind results because air moves from regions of high pressure to regions of low pressure. Learn more about Wind
Many instruments are used to measure wind direction and speed.
Wind direction can be measured using a wind vane. A wind vane has an arrow that points in the direction from which the wind is blowing. Learn more about wind vane
A wind sock has one open end that catches the wind, causing the sock to point in the direction toward which the wind is blowing. Learn more about wind sock
Wind speed can be measured using an anemometer. Anemometers have rotating cups that spin faster when the wind is strong. Learn more about Anemometer