What do you imagine with the word "thermometer"? And with the phrase "street thermometer"? Everyone in his life has come across these devices, but he really does not know what the difference between them is. Maybe there is no difference? In this article you will get answers to all your questions.
What is the difference between a thermometer and a thermometer?
Have you been corrected at least once in your life, saying that a thermometer is not a thermometer, and vice versa? Maybe yes. In each house, you can see a mercury or electronic thermometer for measuring body temperature, and a thermometer measuring the air temperature will hang outside the window. But why are these devices called in different words? Is it right, "thermometer" or "thermometer"? Let's figure it out.
Thermometer or thermometer? How right?
A thermometer is a device with which you can measure the temperature of a body, air, soil, water, etc. A thermometer is nothing more than an absolute synonym for the word "thermometer." They began to call it a thermometer among the people, let’s say, and this name came from the word "degree" (for example, "street thermometer").
Specialists often use the term "thermometer", and the name was given to the device by scientists back in the 17th century. At home, you can measure body temperature with a thermometer or a thermometer - how to do it right? Consider below.
We measure body temperature at home
There are two types of thermometers for measuring human body temperature: mercury and electronic. We have been familiar with mercury since childhood and are more familiar, but it is less practical to use, since it takes at least 7 minutes to determine the temperature. In addition, it is glass and can easily break, and it is almost impossible to collect mercury completely. Mercury vapors are very toxic and dangerous to human health, especially children.
An electronic thermometer is more expensive than a mercury, its temperature readings are not entirely accurate, but using such a device is much safer. In addition, to determine the temperature with an electronic thermometer, it takes only about a minute, and at the end of the measurement the device gives a signal, which is very convenient.
The history of the thermometer
Galileo Galilei - a wonderful scientist and inventor, it was he who owned the discovery of the thermometer. There is no description of this invention in his own writings, but his students testified that Galileo created something like a thermoscope.
It happened in 1597, the device looked like a glass ball with a tube. During the experiment, the end of the tube was lowered into water, the ball was heated, the air inside the ball changed its pressure, respectively, and the volume - water rose up the tube. The thermoscope showed only a change in the degree of cooling and heating of the body without specific numbers, because it did not have a scale.
After 60 years, in 1657, Florentine scientists were able to improve the Galileo thermoscope. They installed a scale on the device and pumped air out of the tube and ball - the quality of temperature measurement immediately increased. Then they changed the thermoscope again, turning it upside down and filling the brandy.
There are several more names that are credited with creating the thermometer: Robert Fludd, Scarpy, Solomon de Caus, Lord Bacon, Sanctorius, Cornelius Drebbel. All sources indicate only air thermometers consisting of a tank and a tube.
In 1667, a liquid thermometer was first described. At first, water was taken for the liquid, but a vessel burst from its freezing, so they began to use wine alcohol. In Paris in 1703, the air thermometer was again improved by the scientist Amonton, who first measured the degree of air elasticity.
Modern thermometer
Key changes brought Fahrenheit, giving the thermometer a modern look. Initially, he also filled tanks and tubes with alcohol, but nevertheless settled on mercury. In 1723, Fahrenheit first described his version of collecting a thermometer, and the surviving specimens are considered to be brilliantly assembled.
In 1742, we all established the well-known scale on the thermometer. Anders Celsius - a Swedish astronomer, meteorologist and geologist - finally determined two constant points on the scale of the thermometer (boiling point and freezing of water). But at the beginning, 0 ° indicated the boiling point, and 100 ° the freezing point.
Later, after the death of Anders Celsius, his compatriots Karl Linney and Morten Stremer turned the scale over (0 began to be considered the freezing temperature, and 100 - boiling water). Such a scale seemed convenient and is still used (for example, in a thermometer for measuring body temperature).
The Reaumur studies led to a new kind of scale, but this was a step backward compared to the Fahrenheit studies. The thermometer made by Reaumur was huge, and the division method on the scale was inaccurate. After Reaumur and Fahrenheit, craftsmen made thermometers for sale.
Types of Thermometers
It is not so important to know how to use a thermometer or a thermometer, it is much more important to be able to use it, given its varieties:
- gas;
- electric;
- fiber optic;
- liquid;
- mechanical;
- thermoelectric;
- infrared.
Next, we consider in detail all types of devices.
Gas thermometer
The principle of operation of a gas thermometer is the same as in a liquid, but the tank is filled with gas. The advantage of such a flask filler is that the range of temperature measurement is increased. Gas thermometers are used to detect extremely high temperatures reaching +1000 ° C.
Digital Thermometer
It works by changing the degree of resistance of the conductor in various temperature conditions: when the metal is heated, the resistance of current transfer increases. The temperature range depends on which metal is used as a conductor.
The base metal is copper, in its range the minimum temperature is -50 ° C, the maximum +180 ° C. Thermometers on platinum indicate a range from -200 ° C to +750 ° C, but such thermometers are more expensive. In everyday life, an electronic thermometer with an external sensor is very popular , it is most often used for a bath - the temperature can be controlled from the outside.
Fiber optic thermometer
It is made using fiber optic. Very accurate sensors of this device allow you to measure temperature with minimal error. The optical fiber is stretched or compressed when the temperature changes, and the beam of light that passes through the fiber is detected by the sensor.
Liquid thermometer
This is the oldest type of thermometer that works by expanding or compressing the liquid in the flask. The liquid level in the vessel rises with increasing temperature, and thanks to the scale it can be measured. These instruments are very accurate, but not entirely practical. They are used not only as thermometers for measuring body temperature, but also for air, water, etc. in various fields of activity.
Mechanical thermometer
The principle of operation of such a thermometer: the arrow on the scale moves due to changes in the physical parameters of the metal wire (spiral). The device resembles a clock with an arrow and is used in various special equipment. An important advantage of mechanical thermometers is their practicality and durability, they are not afraid of shock and shock, like glass models.
Thermoelectric thermometer
There are 2 conductors in the design of the thermometer, with their help the temperature is measured by the Seebeck effect (physical principle). Such devices have a huge range of temperature determination (from -100 ° C to +2500 ° C). The measurement error is not more than 0.01 ° C.
Infrared thermometer
Often used as a thermometer to measure body temperature. The most modern thermometer is considered infrared. The temperature range can reach up to +3000 ° C. In medicine, an electronic thermometer is less and less used, and infrared (non-contact) is gaining popularity. The advantages of this device are that the readings are read without direct contact with the body. This makes it possible to use such a thermometer in dozens of fields of activity: for example, to determine the temperature of a flame or metal in the engine housing.