Many thermometers are thin glass tubes filled with a liquid. Mercury and alcohol are often used
in thermometers because they remain in liquid form over a large temperature range.
Thermal expansion is the increase
in volume of a substance because of an increase in
temperature. As a substance's temperature
increases, its particles move faster and spread out.
So, there is more space between them, and the
substance expands, Mercury and alcohol expand
by constant amounts for a given change in temperature.
1. What is the focus of the written text?
2. What discipline would you classify the above text?​