What is a thermometer? Names and uses of thermometers on the market

Thermometer helps us to check body temperature at any time. Join Tnhelearning.edu.vn to find out what a thermometer is, what types of thermometers are available, as well as the structure and operating principle of the thermometer in the article below!

What is a thermometer?

Define

Thermometer is derived from two Greek words – heat means temperature and thermometer means measure.

A thermometer is an instrument designed to measure and indicate the temperature at a particular environment or object using a variety of principles, depending on the type of thermometer such as mercury thermometers, alcohol thermometer, infrared thermometer, ….

Structure

Thermometers are composed of two main parts :

• The section displays the result information.
• Thermistor part for measuring temperature.

Working principle

When measuring the temperature, the temperature sensor part will expand if it encounters a hot object and contracts when it encounters a cold object. The scale part of the thermometer is designed with low to high temperature so that users can easily check the results after measuring.

Some of the standard units of thermometers are: Celsius (symbol °C) used in Canada/UK, Fahrenheit (symbol °F) used in the US. In addition, the unit Kelvin is also used by scientists in research.

Thermometer uses:

The main use of a thermometer is to measure temperature. Serving many purposes from households to industries, medical such as:

• Monitor and control heat in engines better.
• Measures the temperature in the air conditioning system, providing the user with the appropriate temperature.
• Check food quality.
• To survey buildings for moisture and leaks.
• In the laboratory and storage room.
• Medical body temperature check.

Thermometers have many uses, so you should choose the right thermometer for your intended use, needs, and environment. If your family has small children, this is an extremely necessary tool that you should equip.

Applications of thermometers in life

In medical

In medical environments and applications, thermometers used to measure body temperature help doctors, nurses or users know if you have a fever or not.

Medical thermometers are used with a variety of types, such as: ear thermometers (infrared thermometers), forehead thermometers (liquid crystal thermometers) and rectal and oral thermometers (mercury or thermal thermometers). NTC meter with digital reader).

In production technology

In machinery manufacturing technology, electric thermometers are used in air temperature control systems such as air conditioners, refrigerators, heaters, water purifiers, etc.

Thermometers also play an important role in initiating weather forecasting models and are often used in cold climates to help determine if your area may be freezing.

In addition, thermometers are also used in nuclear power plants to make it easier for staff to monitor the temperature of the reactor core and control to avoid problems, helping to determine energy losses.

For the food industry, thermometers also help to check that food has reached the standard allowed for food preservation. The thermometer helps you to monitor the refrigeration temperature and maintain the temperature in the food.

In the laboratory

In the laboratory thermometers are used in many physical activities. Some temperature sensors are used mostly in scientific experiments and measurement systems.

The most popular types of thermometers today

On the market today, there are 3 types of thermometers that are commonly used in daily life:

• Mercury thermometer: Has a long history and is quite popular to this day.
• Electronic thermometer: A fairly modern device, measuring temperature in many locations on the body.
• Infrared thermometer: As a modern device, this device is safer to use and gives highly accurate results.

In addition, thermometers have many different types such as liquid thermometers, electric thermometers. Some specialized thermometers such as island thermometers, depth thermometers, etc.

Mercury thermometer

Define

A mercury thermometer is a temperature measuring device that uses the expansion property of mercury to measure body temperature. This is a temperature measuring device invented a long time ago and is widely used to this day.

Structure: Mercury thermometer consists of 3 parts :

• Temperature sensing part: It is a mercury container, which has the effect of receiving heat from the environment to be measured, and under the influence of the principle of expansion of matter (specifically, mercury here), depending on the temperature that The expansion of mercury varies, according to which the ambient temperature is measured.
• Capillary tube: A column of mercury that expands when exposed to the environment, thereby measuring the temperature of the environment.
• The display of the results: The number lines, based on the principle of expansion of mercury, that each height of the capillary tube has the corresponding temperature.

Working principle

Mercury thermometers work on the principle that mercury expands with temperature. The change in temperature causes the column to run to expand or pull the mercury in the tube. This activity is immediately displayed with a data confirming the calibration level of the temperature scale.

Measurement location: Underarm area, under arm.

Advantage

• Affordable price should be more cost-effective for users instead of electronic thermometers.
• The structure of the mercury thermometer is quite simple, so it is easy to manipulate and use . It is considered a convenient device that can be used in homes and hospitals.
• Gives results as accurate as an electronic thermometer when used correctly.
• Can be used for continuous measurement of many people.

Defect

• The time for results is long from 3 to 5 minutes , if measured for young children, it may make them fussy and difficult to keep still.
• The result display line is usually small, easily blurred.
• Mercury thermometers have a simple structure, so they do not have modern functions such as high fever warning.
• It must be used correctly to give the most accurate results because using it incorrectly will cause the results to be skewed.
• There is a very high risk of breakage, when broken vaporizes very toxic and dangerous mercury.

Electronic thermometer

Define

Electronic thermometer is a type of thermometer that uses thermal induction technology to measure temperature. Today, this type of thermometer is trusted because of its accuracy and fast measurement speed.

Electronic thermometer was born with simple operation, fast and accurate results, making it get a lot of attention from consumers.

Electronic thermometer construction

Regarding the structure of the basic electronic thermometer, there are 3 parts:

• Sensor: A place to receive the wavelength of the body.
• LCD display unit: This is where your body temperature results are returned.
• Power button: To turn on the electronic thermometer when in use.

Working principle of electronic thermometer

Electronic thermometers are designed to use a thermal sensor to measure temperature. The sensor is connected to a pre-programmed circuit board. As the measurement takes place, the sensor collects information, transmits it to the control panel and then displays the measurement results on the screen.

Measurement location: The most commonly used is the armpit because of its convenience and ease of clamping the thermometer. However, the anus is the most accurate temperature measurement location.

Advantage

• Electronic thermometer is safe and suitable for all subjects . Using high-quality materials with good impact resistance without worrying about cracking.
• For fast, accurate results in just 5-10 seconds .
• Simple, easy to use. Mothers can use it to measure in many different places on the baby’s body.

Defect

• More expensive than mercury thermometers.
• The accuracy of electronic thermometers often deviates from mercury thermometers by about 0.2 – 0.5 degrees Celsius .

Infrared thermometer

Define

Infrared thermometer is a type of thermometer that allows to measure temperature without touching people or objects , measuring based on the principle of measuring the amount of infrared emitted by the body. Infrared thermometers can measure forehead, ear or have built-in forehead and ear thermometers.

Structure of infrared thermometer:

• The sensor part is responsible for receiving the body’s wavelength.
• The LCD screen is located on the thermometer body to display the measured results on the body temperature.
• Adjustment buttons such as power off and on, convert measurement units and can switch from measuring human body temperature to measuring room temperature.

Working principle:

Any object with a temperature above -273 degrees Celsius emits thermal radiation or infrared waves and so does the human body. The infrared sensor will measure the level of energy emitted by the object we want to measure, then calculate and display the result on the LCD screen.

Measurement location: Ear, forehead.

Advantage

• Easy to use , you just need to point at the object to be measured, then press the button and read the results on the screen.
• Provides high accuracy, small error
• There is no need for contact between the object to be measured and the thermometer, so it can be applied in many areas of life
• Can measure the temperature of many other objects such as room temperature, milk, bath water and hazardous locations: hazardous substances, harsh conditions, electrical equipment, etc.

Defect

• The price is quite high.
• Although this thermometer product has a quick time to give results, it is also very susceptible to external influences such as wind, fan, air conditioner, sweat, etc., affecting the results.

Factors to know when choosing to buy a thermometer

With each type of thermometer, there will be different standards to choose from. For mercury thermometers , you should pay attention to the following factors:

• Durable.
• Check the integrity of the product, avoid choosing broken, cracked or cracked products.
• The clear graduated lines are easy to observe and read the temperature.

For electronic, digital, and infrared thermometers, when choosing to buy will be more complicated, you should check the following factors before buying such as:

• The measurement error is low, the accuracy is high, the measurement error ranges from 0.2 – 0.3 degrees Celsius, which is fine.
• Large memory capacity, the larger the capacity, the better, ranging from 25 – 50 measurement results with clear and specific measurement date and time.
• Display screen, easy to observe the parameters and measurement results, should consider choosing products equipped with LCD or LED display.
• Choose products with long battery life, easy to change.
• Has many add-ons.
• Warranty and Reputation.

Above is information about the types of thermometers on the market today, hopefully through this article you can choose the right thermometer to take care of the health of the whole family. If you have any questions, please leave a comment below!