Thermometer, history, working

What is thermometer?

A thermometer is a scientific instrument used to measure temperature. This allows us to quantify the heat or cold of an object, environment or substance.

Thermometer consist of?

Traditional thermometers usually consist of a long, narrow glass tube closed at one end. Inside the tube is a colored liquid, often mercury or alcohol. As the temperature changes, the fluid expands or contracts, causing it to rise or fall in the tube. The tube is marked with a scale, usually in degrees Celsius (°C) or Fahrenheit (°F), which allows us to read the temperature depending on the position of the liquid level.

When using a traditional thermometer, it is important to wait a few seconds for the liquid to settle and give an accurate temperature reading.

History:

The invention of the thermometer has been credited to various scientists and inventors throughout history. Here is a brief overview of its development:

Ancient origin:

Ancient Greece: The philosopher and mathematician Hero of Alexandria described a device called a thermoscope around the 1st century AD. He used the expansion and contraction of air to represent changes in temperature.
Ancient China:

The Chinese have a long history of temperature measurements. In the 1st century AD, Chinese inventor Wang Zhenyi created a device called hong yi, which used the expansion of air to measure temperature.
Galileo Galilei (about 1592):

Italian scientist Galileo Galilei is often credited with inventing the first modern thermometer. He built the device using a glass flask with a long thin tube attached to it. The flask was filled with air or liquid and placed in a container of water. As the temperature changes, the liquid or air expands or contracts, causing the level in the pipe to rise or fall, indicating temperature fluctuations.

Fahrenheit and Celsius scales (18th century):

Santorio Santorio (1612): Santorio, an Italian physician, invented the first medical thermometer. He developed a device known as a thermoscope, which used a tube with a bulb on one end and a scale to measure changes in temperature.

Gabriel Fahrenheit (1686–1736):

Polish-German physicist Gabriel Fahrenheit invented the glass mercury thermometer in the early 18th century. He introduced the Fahrenheit scale, which divided the interval between the freezing and boiling points of water into 180 equal intervals.

Gabriel Fahrenheit (1714):

Fahrenheit, Polish-German physicist, introduced the mercury-glass thermometer. He replaced the water used by Galileo and Santorio with mercury, which had a number of advantages, including greater measurement range and greater accuracy. Fahrenheit also established the temperature scale that bears his name.

Anders Celsius (1742):

Celsius, a Swedish astronomer, proposed another temperature scale known as the Celsius scale (formerly called the Celsius scale). His shell had the freezing point of water at 0 degrees and the boiling point at 100 degrees, with the shell divided into 100 equal parts between these points.

Anders Celsius (1701-1744):

Swedish astronomer Anders Celsius developed a temperature scale where 0 is the boiling point of water and 100 is the freezing point. This scale was later reversed and became known as the Centigrade (or Centigrade) scale.

Daniel Gabriel Fahrenheit (c. 1753):

Daniel Gabriel Fahrenheit, nephew of Gabriel Fahrenheit, improved upon his uncle's thermometer design. He introduced a more accurate mercury thermometer in glass, using standardized smaller glass tubes and improved temperature scales.

Since these early advances, thermometers have continued to evolve and improve. Today, we have several types of thermometers, including digital thermometers, infrared thermometers, and thermocouple thermometers, each suitable for different applications and conditions.

Further improvements and modern thermometers:

Throughout the 19th and 20th centuries, many advances were made in the design and accuracy of thermometers. Improvements included the use of different materials such as alcohol and mercury to measure temperature and the development of more accurate and standardized scales.

Modern thermometers use several principles such as fluid expansion, electrical resistance, and infrared radiation to accurately measure temperature. Digital thermometers, thermocouples, and infrared thermometers are examples of the different types of thermometers available today.
It is important to note that the development of the thermometer was an iterative process involving many inventors and collaborators over the centuries who gradually improved and improved the instrument's design and accuracy.

Construction and working:

An instrument used to measure temperature is called a thermometer.

It works on the principle that some materials exhibit physical changes in response to changes in temperature. There are different types of thermometers, but I'm going to explain the construction and operation of a common thermometer known as a liquid-in-glass thermometer.

Build:
The glass liquid thermometer consists of the following parts:

Glass tube:

This is a narrow, clear glass tube with a narrow opening. The tube is usually made of borosilicate glass, which resists thermal expansion and contraction.

Flask:

The lower end of the glass tube is sealed and expanded to form a flask. This bulb contains a liquid or mercury that expands or contracts with temperature.

Capillary Tube:

The thin opening of the glass tube expands upwards like a capillary tube. The capillary tube is very narrow and allows for easy expansion and contraction of the liquid inside.

Scale:

A scale, usually in degrees Celsius (°C) or Fahrenheit (°F), is printed on the surface of the glass tube to indicate the temperature reading.

To work:

The working principle of a liquid glass thermometer is based on the expansion and contraction of the liquid or mercury in the flask and capillary tube.

Calibration:

Before a thermometer is used, it is calibrated by marking a scale with reference points at known temperatures, such as the freezing and boiling points of water.

Measurement:

To measure temperature, the bulb of a thermometer comes into contact with an object or substance whose temperature is to be measured. Heat is transferred from the object to the liquid or mercury in the lamp.

Expansion or Contraction:

As the temperature changes, the liquid or mercury expands or contracts. This expansion or contraction causes the fluid in the capillary tube to rise or fall.

Temperature Measurement:

Temperature is determined by observing the liquid or mercury level on the scale. The markings on the scale correspond to certain temperature values, allowing the user to read the temperature accurately.

It is important to note that liquid-in-glass thermometers are not suitable for certain applications where rapid or remote temperature measurements are required, as it may take time to reach thermal equilibrium with the object being measured. In such cases, other types of thermometers are used, such as digital thermometers or infrared thermometers.