What is a Nhiệt Kế?
Throughout history, many individuals have contributed to the development of the nhiệt kế (thermometer), including Cornelis Drebbel, Robert Fludd, Galileo Galilei, and Santorio Santorio. The word “nhiệt kế” originates from the Greek words “nhiệt” meaning “temperature” and “kế” meaning “measuring.” So, what is the purpose of a nhiệt kế? Simply put, it is a device used to measure temperature.
A nhiệt kế is a tool used to measure temperature or temperature gradients via various principles. It is capable of measuring the temperature of solids, liquids, or gases.
How Does a Nhiệt Kế Work?
The construction and operation of a nhiệt kế are based on the expansion of a liquid due to heat. Its components include a bulb containing the liquid, a glass tube, and a calibrated scale.
To calibrate the scale, the nhiệt kế is immersed in melting ice, and the liquid level inside the tube is marked as the 0⁰C position. Similarly, when the nhiệt kế is immersed in boiling water, the level of the liquid inside the tube is marked as the 100⁰C position. The range between 0⁰C and 100⁰C is divided into ten equal parts, with each part representing 10⁰C.
Temperature measurement is achieved by heating the nhiệt kế, causing the liquid to expand and the column to lengthen. Conversely, when the temperature decreases, the liquid contracts, causing the column to shorten.
Today, nhiệt kế is calibrated in standard temperature units such as Celsius, Fahrenheit, or Kelvin, depending on its application.
Applications of the Nhiệt Kế
The applications of nhiệt kế are wide-ranging, from household use to various industries. In the kitchen, it can be used to measure the temperature of food. Similarly, in a refrigerator, it helps maintain the set temperature. In a factory, a nhiệt kế in an oven allows for turning the oven on and off. Therefore, it is crucial to choose the appropriate type of nhiệt kế for the intended application.
Here are some common applications of nhiệt kế:
- Temperature measurement in engines or monitoring
- Air conditioning systems
- Transportation and on-site testing of automobiles
- Checking food temperatures
- Detecting hidden issues
- Surveying buildings to detect humidity and leakage
- Determining energy losses, poor insulation, electrical faults, and plumbing issues
- Laboratory and storage room use
Each application requires a specific type of nhiệt kế.
Nhiệt Kế: How to Use a Medical Thermometer
A medical nhiệt kế has a characteristic design with a bulb close to the end and a narrow tube. After removing the nhiệt kế from the body, the mercury contracts and is unable to return to the bulb due to the narrowing in the tube. This feature allows us to accurately measure the current body temperature. But what exactly does a mercury thermometer measure?
Here is how to use a medical mercury thermometer:
- Hold the end of the thermometer firmly and vigorously shake it down to below 35⁰C.
- Place the mercury thermometer in the desired location and secure it for at least 5-7 minutes.
- Withdraw the thermometer and read the displayed result.
Note on Using Mercury Thermometers
Caution must be exercised when using a mercury thermometer to prevent the release of mercury particles, which can be hazardous to health. Make sure you are familiar with the five characteristics of a medical nhiệt kế.
Here are the steps to handle a broken mercury thermometer:
- Close all doors and windows to prevent mercury from vaporizing into the air.
- Shine a light on the area where the mercury has spilled to locate even the smallest particles.
- Wear gloves and a mask, then use a soft brush to sweep up and collect all the mercury particles in a lidded container.
- You can use damp newspaper to collect the mercury. After 1-2 hours of collection, clean the area with soap and detergent to ensure proper hygiene.
- If clothes come into contact with mercury, soak them in cold water for approximately 30 minutes, followed by soaking them in soapy water at a temperature between 70-80 degrees. Finally, immerse them in a high-temperature water solution and rinse with cold water.
Remember, proper handling of a mercury thermometer is essential to ensure safety.
By Ánh Phạm
