Edit the definition of thermometer in this paragraph. Thermometers are also called "medical thermometers". The working substance of thermometer is mercury. Its vacuole volume is much larger than that of the upper tubule. Due to the influence of body temperature, the mercury in the bubble changes slightly, and the expansion of mercury volume makes the length of mercury column in the tube change obviously. The temperature of human body generally varies from 35℃ to 42℃, so the scale of thermometer is usually from 35℃ to 42℃, and the range of each degree is divided into 10, so the thermometer can be accurate to110. The neck near the vacuole at the lower part of the thermometer is a very narrow curved neck. When measuring body temperature, the volume of mercury in the vacuole expands when heated, and mercury can rise from the neck to a certain position in the tube. When it reaches thermal equilibrium with body temperature, the mercury column is constant. When the thermometer leaves the human body, the outside temperature is low, and the volume of silver shrinks when it meets cold water, and it is disconnected at the narrow and curved neck, so that part of the mercury that has risen into the tube cannot return, and the mercury column remains high when it contacts the human body. Thermometer is one of the highest thermometers, which can record the highest temperature measured by this thermometer. After use, the thermometer should be "put back on the table", that is, the upper part of the thermometer should be forcibly dropped, so that the mercury that has risen to the tube can return to the vacuole. Other thermometers must not shake, which is a major difference between thermometers and other liquid thermometers. The basic thermometer is used to measure the basic temperature of the human body just after waking up in the morning. Compared with daily body temperature, basal body temperature is less affected by environmental factors, such as exercise or diet. This is helpful to detect the subtle changes of daily body temperature. For example, during ovulation or when the function of line A changes. The scale of glass thermometer should be at least 0.2? F (0. 1？ C), but the basic thermometer needs at least 0. 1? F (0.05？ C) accuracy. Therefore, the basic thermometer made of glass is sold separately from the ordinary thermometer made of glass for fever. But all electronic thermometers have at least 0. 1? F (0.05？ C) accuracy, so it can be used as a basic thermometer. Some digital thermometers are specially marked as "basic thermometers" and are designed with special functions, such as large display screen, extra storage function and so on. Or they will make a sound to guide the correct placement. The first thermometer was invented by Galileo in16th century. But it was not until 300 years later that a thermometer with convenient use and reliable performance was designed. Close-up photo of mercury thermometer. Mercury is stored in the last mercury ball. When mercury is heated, it will expand and rise along a narrow glass tube. Therefore, a small change in body temperature will lead to a large increase in mercury in glass tubes. After taking your temperature, you have to shake the thermometer vigorously to make the mercury return to the mercury ball. 17 14 years, Gabriel Wallenheart developed a mercury thermometer, the scale is in the range of freezing point of water and human body temperature. A Dutch doctor used it to measure the temperature of patients with fever, but the thermometer was still too big for most doctors to use quickly. 1868, German professor Wendelich published a book "Disease and Body Temperature", which recorded the temperature changes of 25,000 patients. The thermometer he used was twice as big as Allbutt, and it took him 20 minutes to record the temperature at a time! About 1980, a talking thermometer was invented. The thin film liquid crystal thermometer is green when the body temperature is normal, yellow when the temperature is low, and red when the temperature is high. 1988 An electronic respiratory pulse thermometer appeared, which can be used for telemetry. Later, in 1867, Allbutt designed a thermometer that can measure body temperature quickly and accurately, and its length is only about 15cm. Unfortunately, Allbutt's thermometer came out too late to help Karl Vunderlikh. Edit the location of this measurement ● The collection of oral temperature is based on the patient's ability to correctly and safely place the thermometer in the oral cavity. That is to say, children or people who are unable to resist coughing, weakness or vomiting are excluded. (This is not a problem for fast-response electronic thermometers, but it is an important topic in mercury thermometers, because it takes a long time for mercury thermometers to respond to temperature. Another point to note is that if the patient drinks hot or cold drinks before using the oral thermometer, other temperature measurement methods must be considered. ● When measuring rectal temperature, especially when measured by another person, lubricant should be used to help. Although rectal temperature is the most accurate, it is embarrassing to consider such behavior in some countries or cultures. In addition, if the thermometer is inserted wrong, it will make the patient feel uncomfortable and even painful. Infants usually use rectal temperature measurement, however, it is more appropriate to use nurses to operate. ● On the ear or forehead, there are an in-ear thermometer for measuring the eardrum and a forehead thermometer for measuring the forehead. If the glass of a modern thermometer is broken, the mercury in the thermometer will do harm to the human body. A new thermometer is made of plastic and can be used for babies or young children. The normal temperature is 37 degrees Celsius. Measuring principle: The characteristics of liquid thermometer are: (1) can be separated from the measured object; (2) It contains more mercury; (3) it has a contraction; (4) The scale value is 0. 1℃ necking: After measurement, mercury cannot retreat from the glass bulb, so it can be edited without reading the reading of the measured object. According to measurement experts, the most common thermometer is the glass thermometer, which can keep the mercury column rising with body temperature in its original position, which is convenient for users to observe at any time. Because of the compact structure of glass and the very stable performance of mercury, the glass thermometer has the characteristics of accurate indication, high stability, low price and no need for external power supply, and is trusted by people, especially medical workers. However, the defects of glass thermometers are also obvious, and they are easy to break, which may lead to mercury pollution. It takes a long time to measure, which is inconvenient for acute and severe patients, the elderly, infants and so on, and the reading is more troublesome. Electronic thermometer With the development of science and technology, many new types of thermometers have appeared. Electronic clinical thermometer uses the definite relationship between physical parameters of some substances (such as resistance, voltage and current) to display body temperature in digital form. And the reading is clear and convenient to carry. Its disadvantage is that the accuracy of indication is influenced by electronic components and battery power supply, which is not as good as glass thermometer. Ear temperature gun is generally used in armpit, mouth, rectum and other places. In practical application, people generally feel inconvenient or uncomfortable. Ear thermometer measures the temperature of human body in a non-contact way by measuring the radiation brightness of eardrum. Just aim the probe at the internal auditory canal and press the measurement button, and the measurement data can be obtained in just a few seconds, which is very suitable for patients with acute diseases, the elderly, infants and so on. However, in the initial stage of use, users may get several different measurement data because they are not familiar with this operation mode. Generally speaking, the maximum value measured is the desired data. Users will be more satisfied with this thermometer after they are familiar with it. The new technology of chip thermometer has brought a very strange thermometer, which can be called chip thermometer or dot matrix thermometer. This thermometer is only the size of a business card, 6 ~ 7 cm long and 0.5 cm wide, and it is covered with some neatly arranged dots with numbers. After the body temperature test, all points below a certain value will become dark, while the colors of other points will remain unchanged. Users can determine the body temperature according to the above changes. This thermometer is inexpensive, small in size, easy to carry and store, and has little pollution. It is especially suitable for medical institutions and can be used once to avoid cross infection. Experts said that the glass thermometer belongs to the national compulsory verification measuring instruments, which has a long history of production and use, and is basically standardized in product quality and supervision and management. However, many electronic thermometer and ear temperature guns used to appear in the market as health care products and gifts, but they have not been strictly and effectively supervised and managed by relevant state departments. Experts remind consumers that if they want to choose digital and ear thermometers for temperature measurement, they need to pay attention to the following aspects: First, because the temperature measurement requirements are strict, the thermometer is generally required to have an error of 0. 1 Celsius, and the accuracy of the thermometer purchased by consumers must meet this requirement. Second, read the instructions carefully and pay attention to the main points of operation. When it is first used, it can be compared with the glass thermometer to judge whether it is used correctly. Third, when using the underarm measurement method, you must clamp it hard to ensure that the thermometer is in full contact with the human body. When oral measurement is used, the thermometer must be placed under the tongue and pressed down slightly. It must be cleaned and disinfected after measurement. No matter what kind of thermometer you choose, it is best to have one for each person to avoid cross-infection.

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