Thermometers in our time have become an integral part of the first-aid kit in every family to measure body temperature in case of illness. But few people think about the principle of its work. What will happen if you shake a medical thermometer.
Types of thermometers
The following types of thermometers exist on the sales market:
- Mercury.
- Electronic.
- Infrared.
Electronic or digital thermometers work on the basis of a thermistor, which is quite sensitive to temperature. The result is displayed on the screen.
Infrared is based on the measurement of heat emitted by the surrounding tissue. There are ear and forehead thermometers.
But still, in the modern world, it is mercury ones that remain the leaders in sales. They are also classic versions of the measuring device.
The principle of operation of mercury thermometers
A mercury thermometer is a thin glass tube sealed on both sides. In the middle is a reservoir with mercury, which passes into the capillaryhandset. The medical mercury thermometer has its own peculiarity: the narrowing between the tank and the capillary tube. When heated, the mercury begins to expand and move upward, indicating human temperature. Then it cools down, and the bottleneck does not allow it to return to the tank. To do this, you need to shake the medical thermometer. What should happen before each measurement of body temperature.
Because if you take a medical thermometer and shake it sharply, the substance acquires a force that makes it move down the capillary. According to the laws of physics, mercury falls back into the tank. Accordingly, the result on the scale is lost.
Sometimes patients complain that they cannot knock down the mercury in the thermometer. Therefore, first shake the medical thermometer. Only then give it to a weakened person. Alternatively, patients prefer to use electronic thermometers.
Shake the medical thermometer in the air and away from hard objects such as a wall or table to avoid damaging it. Because mercury is a dangerous substance, and mercury vapor that enters the lungs of a person poisons the body and leads to serious diseases. Always be careful.
