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A liquid
thermometer
Temperature
Temperature is a measure of how hot the air is. Temperature
is measured with a thermometer. There are many kinds of
thermometers. The most common kind is a liquid thermometer.
A liquid thermometer is a thin glass tube connected to a small
bulb of liquid. As the liquid warms and cools, it expands and
contracts. The height of the column of liquid in the tube changes
in response to the temperature. By labeling the liquid tube to show
temperatures, the meteorologist can read the temperature directly
from the thermometer.
Metals also expand and contract in response to temperature
change. Some thermometers use strips made of two different
metals to detect temperature changes. These are called bimetallic
thermometers. The two metals have different rates of expansion.
One side of the strip expands more than the other as it
heats
up,
and the strip bends. A pointer on the end of the bending strip
points to the temperature.
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