A barometer is a geographical piece of equipment that is used to measure air pressure. It is calibrated in the imperial measurement inches. It can also be used with the metric unit millimeters or millibars.
The type of air pressure has different weather conditions related with it. For example; when the air pressure increases through the barometer it is an indication that there are signs of convalescing weather.
Depending on the type of barometer, if it electronic it is more versatile, so it can store air pressure readings and illustrate the air pressure trends that have occurred over a period of time. For instance, if there is a downward trend of air pressure over a period of time this is a sign that stormy weather lies ahead.
Many people across the globe take their own weather analysis everyday; some people go a step further by forecasting the weather themselves. It is an interest and hobby for people around the world. A barometer is invaluable to the people that take up this hobby because it allows them to see how the air pressure is changing, thus allowing them to predict the future weather forecast.
___ Setting a barometer up ___
Before you can predict the weather and take an accurate reading of the flow of air pressure, it is essential to make sure that the barometer is set correctly.
1) Firstly identify the type of barometer you have. The most common types of barometers used are either “aneroid” or mercury”. These particular set of instructions are for aneroid barometers.
2) You then should check the alteration screw on the back of the aneroid barometer. Make sure you read the instructions that came with your barometer, so that you can find out if you need to turn this screw, to set up the instrument to the current pressure reading. It is essential that you do this task effectively to determine the precision of your result.
3) Then you should call your local weather service or check online, although make sure it is a reliable source, to clarify the current barometric reading.
4) After you have found the barometric reading you should set the barometer to this reading you have obtained.
5) Now check your barometer and find the two needles supplied with it. Depending on the versatility of your barometer the two needles may automatically pick up on the atmospheric pressure whilst others barometers need the two needles to be moved manually by hand. If you have any queries about this check the manual, as this instruction differs with different barometers.
6) Now set the movable dial to correspond with the needle marking the current air pressure.
7) Watch the needles as they follow the pressure changes as it moves up or down to coincide from that fixed point. Before you note down a reading you should tap the barometer lightly.
8) Once you have taken down a reading compare it to the reading that you noted down from the weather report, this allows you to check the accuracy of your result.
___ An invaluable Tip ___
The best day to set up your barometer is on a day with anticyclonic conditions when the pressure does not alter too much. Anticyclones are areas of high pressure and generally bring calm weather. In summer the conditions bring clear skies and low wind speeds, the temperatures are usually high and there is generally dry weather. In the winter the anticyclonic conditions bring stable air pressure and clear skies although the temperatures may be lower, this is due to the lack of cloud cover.
So, forget watching the weather forecast on television; with the barometer you can predict the weather for yourself! Go on have a try!
Sources
http://www.quicksilver-barometers.co.uk/barometer_information.html#calc
http://www.bbc.co.uk/weather/features/setting_barometer.shtml
http://www.ehow.com/how_18498_set-read-barometer.html
http://weather.about.com/od/lessonplanshighschool/a/anticyclones.htm
