What is the filler material in a temperature probe?

Generally, the filler in thermometers is mercury, also known as quicksilver, a metal that is liquid at room temperature. The detailed explanation is as follows:

Mercury is the only metal that remains liquid at room temperature and is an ideal filler for thermometers. It has a moderate coefficient of thermal expansion, allowing it to accurately reflect changes in body temperature. The working principle of a mercury thermometer is based on thermal expansion and contraction. When body temperature rises, the mercury expands and rises; when body temperature decreases, the mercury contracts and falls. By reading the height of the mercury column, body temperature can be accurately measured. Although mercury thermometers are highly accurate, mercury is a toxic substance, and if the thermometer breaks or leaks, it may pose risks to human health. Therefore, mercury thermometers should be handled with special care to avoid breakage or leakage.

In summary, mercury is the filler used in thermometers, accurately measuring body temperature based on the principle of thermal expansion and contraction. However, due to its toxicity, mercury thermometers must be used with caution, and safer alternative products should be considered.