The Thermometer is used to measure air
A thermometer measures temperature.
Liquid-in-glass thermometers are the most common types of thermometers because they are easy to read and
inexpensive to construct.
thermometers are made from glass and consist of a glass bulb that is attached to a tube that is marked with a
temperature scale. The liquid in the thermometer is usually alcohol or mercury. When this liquid warms up, the
molecules in the liquid move faster and the volume expands. The expansion of the liquid causes it to move up
into the bore and indicate the temperature. When the liquid cools, it contracts and moves back into the bulb,
indicating a low temperature.
thermometer with a constriction is used to measure the maximum temperature. These types are thermometers are
also used to measure the body temperature of humans. As the temperature increases, the liquid moves up into the
bore; however, as the liquid cools, it cannot freely move downward again because of a constriction in the bore.
In order to lower the liquid in the bore, it must be reset by applying forces to the thermometer sufficient to
push the liquid bask into the bulb.
The Hand Anemometer is a small
portable instrument that gives a direct reading of wind speed.
Wind is air in motion. Differences in air temperature
create differences in atmospheric pressure which, in turn, initiate air motion. This movement is modified by
the rotation of the earth, which causes the wind to deflect to the right in the Northern Hemisphere. Another
important factor is friction. High above the earth the flow of air is smooth and continuous. At or near the
ground this uniform flow is disturbed by the irregularities of the earth's surface. Generally, the effect of
these irregularities is to make the flow lighter but more variable, with lulls and