Thermometers in our time have become an integral part of the first-aid kit in every family for measuring body temperature in diseases. 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 are based on a thermistor, which is quite sensitive to temperature. The result is displayed on the screen.
Infrared is based on measuring the heat that the surrounding tissue emits. There are ear and frontal thermometers.
But nevertheless, in the modern world mercury remains the sales leaders. They are classic versions of the measuring device.
The principle of operation of mercury thermometers
The mercury thermometer is a thin glass tube sealed on both sides. In the middle is a mercury tank that passes into the capillary tube. A medical mercury thermometer has its own peculiarity: the narrowing between the reservoir and the capillary tube. When heated, the mercury begins to expand and move upward, showing human temperature. Then it cools, and the bottleneck prevents it from returning to the tank. To do this, you need to shake the medical thermometer. What should happen before each measurement of body temperature.
Therefore, if you take a medical thermometer and shake it sharply, the substance gains strength, which makes it move down the capillary. According to the laws of physics, mercury is lowered back into the tank. Accordingly, the result on the scale gets confused.
Sometimes patients complain that they cannot bring down mercury in a thermometer. Therefore, first shake the medical thermometer. Only then give it to a weakened person. As an alternative, patients prefer to use electronic thermometers.
Shake the medical thermometer in the air and away from solid objects such as a wall or table to avoid damage. Because mercury is a dangerous substance, and mercury fumes that enter the lungs of a person poison the body and lead to serious illnesses. One must always be careful.