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Know how to get weather information from a thermometer, barometer, and an anemometer.
THERMOMETER
Developed during the 16th and 17th centuries, a thermometer (from the Greek θερμός (thermo) meaning
"warm" and meter, "to measure") is a device that measures temperature or temperature gradient using a
variety of different principles. A thermometer has two important elements: the temperature sensor (e.g.
the bulb on a mercury thermometer) in which some physical change occurs with temperature, plus some
means of converting this physical change into a numerical value (e.g. the scale on a mercury
thermometer).
There are many types of thermometer and many uses for thermometers, as detailed below in sections of
this article.
Temperature
While an individual thermometer is able to measure degrees of hotness, the readings on two thermometers
cannot be compared unless they conform to an agreed scale. There is today an absolute thermodynamic
temperature scale. Internationally agreed temperature scales are designed to approximate this closely,
based on fixed points and interpolating thermometers. The most recent official temperature scale is the
International Temperature Scale of 1990. It extends from 0.65 K (−272.5 °C; −458.5 °F) to approximately
1,358 K (1,085 °C; 1,985 °F).
BAROMETER
A barometer is a scientific instrument used in meteorology to measure atmospheric pressure. It can
measure the pressure exerted by the atmosphere by using water, air, or mercury. Pressure tendency can
forecast short term changes in the weather. Numerous measurements of air pressure are used within
surface weather analysis to help find surface troughs, high pressure systems, and frontal boundaries.
Aneroid barometers
An aneroid barometer, invented by the French 19th century engineer and inventor Lucien Vidie, uses a
small, flexible metal box called an aneroid cell. This aneroid capsule (cell) is made from an alloy of
beryllium and copper.[9] The evacuated capsule (or usually more capsules) 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. Many models include a manually set needle
which is used to mark the current measurement so a change can be seen. In addition, the mechanism is
made deliberately "stiff" so that tapping the barometer reveals whether the pressure is rising or falling as
the pointer moves.
ANEMOMETER
An anemometer is a device for measuring wind speed, and is a common weather station instrument. The
term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed
measurement instrument used in meteorology or aerodynamics. The first known description of an
anemometer was given by Leon Battista Alberti around 1450.
Anemometers can be divided into two classes: those that measure the wind's speed, and those that
measure the wind's pressure; but as there is a close connection between the pressure and the speed, an
anemometer designed for one will give information about both.
Cup anemometers
The three cup anemometers are currently used as the
industry standard for wind resource assessment
studies.
Windmill anemometers
The other forms of mechanical velocity anemometer may
be described as belonging to the windmill type or
propeller anemometer. In is type of anemometer the
speed of the propeller show the speed of the wind, and
the direction
is measured
by theFurthermore,
angle of the since
vane.the wind
wind
and therefore
horizontal.