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2.
Introduction
Thank you for your purchase of the Ambient Weather WS-152B 6" Contemporary Barometer. The
following is a guide for preparation, care and operation of your weather instrument.
3.
Preparation
Your weather instrument includes a protective pad to prevent damage to the barometer mineral glass
case during shipment. Remove this protective pad and circular instruction sheet. The barometer is
ready to use.
4.
Care and Cleaning
Avoid use of harsh household cleaners and coarse paper towels, which can scratch the bezel or lens.
Fingerprints and dirt may be removed the lenses and bezels with a soft cloth lightly dampened with a
mixture of water and mild dishwashing liquid. Be sure to dry the lens and bezel with a soft cloth
after cleaning.
5.
Barometer Operation
4.1 How the aneroid barometer works
An aneroid barometer uses a small, flexible metal box called an aneroid cell. This aneroid capsule
(cell) is made from an alloy of beryllium and copper. The evacuated capsule is prevented from
collapsing by a strong spring. Small changes in external air pressure cause the cell to expand or
contract. This expansion and contraction drives mechanical levers such that the tiny movements of the
capsule are amplified and displayed on the face of the aneroid barometer. This model includes a
manually set gold needle which is used to mark the current measurement so a change can be seen. It
was invented by Blaise Pascal.
4.2
Reading the barometer
The ability if the barometer to indicate changes in barometric pressure makes it a useful instrument in
weather forecasting.
The weather forecast or pressure tendency is based on the rate of change of barometric pressure. In
general, when the pressure increases, the weather improves (sunny to partly cloudy) and when the
pressure decreases, the weather degrades (cloudy to rain).
The weather forecast is an estimation or generalization of weather changes in the next 24 to 48 hours,
and varies from location to location. The tendency is simply a tool for projecting weather conditions
and is never to be relied upon as an accurate method to predict the weather.
The barometer includes a manually set gold needle, which is used to mark the current measurement so
a change can be seen. Barometric readings should be taken daily. Remember that the rate of change
of barometric pressure is important in determining weather changes. You may want to take multiple
readings each day during periods of unstable weather conditions.
The following basic rule of thumb will hold true in using the barometer to predict weather conditions.
A fast rise in barometric pressure means good weather of short duration.