The Past and the Present of Thermometers

Nowadays, almost every family has an digital thermometer. So, today we’re going to talk about the past and present of thermometer.

MT-301 digital thermometer
One day in the year of 1592, the Italian mathematician Who named Galileo was giving a lecture at the University of Padua in Venice, and he was doing a water pipe heating experiment while speaking. He found that the water level in the tube rises due to the heating of the temperature, and the temperature drops when it cools down, He was thinking of a commission from a doctor friend not long ago: “When people are sick, their body temperature usually rises. Can you find a way to measure the body temperature accurately? , to help diagnose the disease?”
Inspired by this, Galileo invented the bubble glass tube thermometer in 1593 by using the principle of thermal expansion and cold contraction. And in 1612, with the help of friends from different fields, the thermometer was improved. Red stained alcohol was installed inside, and the 110 scales engraved on the glass tube can be used to see the temperature change, which can be used to measure body temperature.This is the earliest thermometer in the world.
From the “past” of the thermometer, we can know that the latest mercury thermometer also uses the same principle of thermal expansion and cold contraction, the only is that we replace the liquid in the thermometer with mercury.

glass thermometer
However, The mercury is highly volatile heavy metal substance. It is reported that a mercury thermometer contains about 1 gram of mercury. After being broken, all the leaked mercury evaporates, which can make the mercury concentration in the air in a room with a size of 15 square meters and a height of 3 meters 22.2 mg/m3. People in this environment of such mercury concentration will soon cause mercury poisoning.
The Mercury in mercury glass thermometers not only gives a direct risk to the human body, but also causes serious damage to the environment.
For example, if an abandoned mercury thermometer is damaged and discarded, the mercury will be volatilized into the atmosphere, and the mercury in the atmosphere will fall into the soil or rivers with rainwater, causing pollution. The vegetables grown in these soils and the fish & Shrimp in the rivers will be eaten by us again, causing a very serious vicious circle.
According to the Announcement No. 38 issued by the former Ministry of Environmental Protection in conjunction with relevant ministries and commissions in 2017, the “Minamata Convention on Mercury” came into effect for my country on August 16, 2017. it stated clearly that Mercury thermometers and mercury blood pressure monitors are forbidden to manufacture from 1st/Jan of 2026.”
Of course, Now we already have better and safer alternatives: digital thermometer,infrared thermometer and Indium tin glass thermometer.
Digital thermometer & infrared thermometer both are composed of temperature sensors,LCD screen, PCBA, chips and other electronic components. It can measure body temperature quickly and accurately. Compared with the traditional mercury glass thermometer,they have the advantages of convenient reading, fast response, high accuracy, memory function, and beeper alarm. Especially the digital thermometer does not contain any mercury. Harmless to the human body and the surrounding environment, it is widely used at homes, hospitals and other occasions.
At present, Many hospitals and families in some big cities have replaced mercury thermometers with digital thermometer and infrared thermometer. Especially during the COVID-19 period, infrared thermometers were irreplaceable anti-epidemic “weapons”. we believe that with the country’s Propaganda, everyone’s popularity of the hazards of mercury, mercury series products will be retired in advance.and digital thermometer will be widely used in every place such as home,hospital and clinic.

Post time: May-26-2023