Barometers And Past Weather Predict Future

The typical classic mercury barometer is a glass tube that is almost three feet high and is packed with mercury. The tube lies upside down in a reservoir, which holds the mercury. It was invented by Evangelista Torricelli in 1643. By recording rainfall data, wind speeds and trends, it was past weather that helped him understand how barometric pressure works. A barometer is a useful tool in predicting the weather and meteorologists use them to understand when a low front that brings rain and wind is on its way.

Air rising away from the earth's surface faster than it can be substituted by air streaming in from surrounding areas creates a low pressure zone. This decreases the weight of the air over the barometer reservoir; thus the mercury level moves to a lower level. Conversely, in high pressure zones, air is moving towards the earth's surface faster than it can stream out to surrounding zones. This produces more air over the reservoir; thus the air's weight surges higher and the mercury level moves higher to create equilibrium.

Large, gradual and continual drops in pressure will forecast a long episode of unusually bad weather. Expect the weather to be more pronounced if the atmospheric pressure went up before it started to fall. Conversely, a large, gradual and continual increase in pressure indicates that an approaching episode of long-lasting good weather is expected. If there is a quick rise in pressure when times are fair and moderate or there is above average pressure, then this means that there is a coming low pressure episode. Scientists gather past weather information in order to understand this phenomenon.

An example of barometric pressure is when a rubber suction cup is pressed against a smooth surface, as it will remain stuck. By simply pressing the cup down flat against the wall surface, the air is expelled from the area under the cup and a vacuum is then formed. The pressure of the air which originally acted in that area now no longer thrusts against the inside of the cup. When it is released, it will stay in the compressed position because the air pressure is acting on the outside only and therefore presses the edge of the cup down so firmly that no air can penetrate into the area which remains void of air.

You can typically depend on the reliability and consistency of a barometer at predicting weather conditions. It is known that the atmospheric pressure of any particular altitude is never constant, and varies by generally small amounts from average. These variations in barometric pressure provide data for weather forecasts. Past weather data combined with the use of a barometer has helped scientists predict the weather for hundreds of years.