Thinking about buying a glass thermometer but not sure how to choose?
With the following 5 quick tips, SJ Gauge helps you gain a deeper understanding of glass thermometers in just five minutes.
1. Types of general thermometers
Thermometers with silver liquid are mercury thermometers, while those filled with red or blue liquid are called alcohol thermometers.
2. Is there really alcohol inside an alcohol thermometer?
Although it is called an alcohol thermometer, the liquid inside is not actually alcohol but a petroleum-based liquid (dyed red or blue, such as diesel). The name comes from early designs that used alcohol, and it has been retained ever since. However, mercury thermometers do indeed contain mercury.
3. Can a general thermometer be used directly as a body thermometer?
A general thermometer does not immediately display body temperature when measuring. The human body gradually releases heat, and the thermometer only shows the correct reading after heat transfer between the body and the thermometer reaches equilibrium, which takes time. In addition, once the thermometer is removed from the body, the reading will drop due to the surrounding air. Therefore, clinical thermometers are designed so that the temperature does not drop immediately after removal.
4. Are mercury thermometers hazardous?
Due to environmental concerns and the risk of mercury poisoning, some countries and regions have banned the use of mercury thermometers. In Taiwan, they are now rarely available on the market. If a mercury thermometer breaks, sulfur powder can be applied to react with the liquid mercury and form solid mercury sulfide, making it easier to collect the highly toxic substance.
5. Why does my glass thermometer drop automatically?
In practice, the upper part where the liquid column connects to the bulb is slightly constricted to prevent the liquid from flowing back. After use, the liquid column does not drop automatically and must be shaken down or left to rest for a while. If the liquid drops too quickly, the thermometer should be discarded.
