What is a barometer?
Just about everyone has heard the nightly weather report include the forecaster stating "the barometer is falling" but just what does that really mean?
A barometer measures rising and falling air pressure - a falling barometer means a decrease in air pressure while a rising barometer indicates increasing air pressure.
Air pressure has a very pronounced effect on the weather and, by knowing about barometric pressure, you are able to make certain predictions about the weather.
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What is a thermometer?
Simply put, thermometers measure changes in temperature. Bulb thermometers operate on a basis that liquid changes its volume relative to its temperature; other thermometers tell you the temperature in the furnace, how high your fever is or room temperature.
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What is an anemometer?
An anemometer is the modern descendent of the weather vane. The anemometer (or wind gauge) measures wind speed and direction. Tiny cups on the anemometer capture the wind and spin round and round. The revolutions-per-minute of the cups determines wind speed. Anemometers also help determine wind chill temperature.
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What is the Beaufort Wind Scale?
Many weather instruments use the Beaufort Wind Scale as the method of estimating and reporting wind speeds. The scale was developed by Sir Francis Beaufort in the early 1800s for the British Royal Navy.
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What is a thermo-hygrometer?
A thermo-hygrometer measures both temperature and humidity.
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What is humidity?
Humidity is the amount of water vapor present in the air. When someone says "Boy, it's humid today" what they're really saying is that there's a lot of water vapor in the air!
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What is relative humidity?
Relative humidity is the ratio of the amount of water vapor present in the air compared to the greatest amount possible at the same temperature.
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What is dew point?
The dew point is the temperature at which the water vapor present in the air begins to condense.
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What is condensation?
Have you ever noticed that fog on your windows eventually turning into water and settling on the bottom of the window sill? That, in effect, is what condensation is all about - the process by which water vapor undergoes a change from a gas to a liquid.
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What are the differences between degrees F and C?
Gabriel Fahrenheit, a German physicist, created the Fahrenheit temperature scale in 1714. It is a temperature scale based upon water at sea level having a freezing temperature of 32 degrees F and a boiling point of 212 degrees F. This form of temperature measurement is common in the United States.
Celsius is a temperature scale where the freezing point of water at sea level is set at 0 degrees C and has a boiling point of 100 degrees C. This form of measurement is most commonly used in countries which observe the metric system of measurement.
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 Learn About Predicting the Weather
Learn About Weather Equipment
Learn How Atomic Clocks work
Learn About Weather Radios
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