In the indoor environment, test and read (in the drawing circles) photo/law evening reporter ro xiaoqing
In the freezer environment, test and read (in the circle of pictures) photo/law evening reporter ro xiaoqing
In the outdoor environment, test and read (in the circle of pictures) photo/lawy evening reporter ro xiaoqing
In the case of the greenhouse, test and read the photogram
After cooling, many citizens purchase thermometers to measure whether the temperature in their homes is met. Citizens reported to the law and order evening that they had purchased different thermometers, but that the results varied。
Journalists have purchased commonly used pointers, glass tubes and electronic digital thermometers, which are sent to specialized laboratories, tested in four different settings, such as constant temperatures, colds and constant heat, and compared to standard thermometers. The results show that glass tube thermometers have the smallest error to standard thermometers, with the greatest error in multifunctional electronic thermometers, with a maximum difference of 5°c, within 0. 5°c. According to experts from the beijing academy of metrology and testing, there are currently no measuring and measuring protocols for electron thermometers, resulting in temperature errors that cannot be judged in actual tests。
I'm worried
Temperature measurements are different
The citizens are very upset
"there's a silver thermometer on the wall of the living room and a pointer in the baby's bedroom." since last month's heating of the house, ms. Jiang has been staring at the temperature scale of the house, to see if room temperature meets the heating standard of 18°c, and for a few days she has observed that the temperature shown by the two thermometers is “different”。
"at first, i thought it was a different location, so the temperature was different, but then i put both thermometers in the living room, showing different degrees, 17. 5 degrees for mercury and 18. 5 degrees for the pointer." ms. Chiang said that she had subsequently bought another electron thermometer and that the temperature was still different。
“the salesman at the time of the purchase said the electronics were more accurate, and it was not surprising that they were more than one degree higher.” ms. Chiang was upset by different temperature measurements, "i also asked the property to see if there was a problem with the heating tablets, checked several times, and the air was released. No matter how much trouble it is, the thermometers you buy don't matter
Try it
Three thermometers
Temperatures vary
During the weekend, journalists visited several supermarkets and community convenience stores and found that there were thermometer sales, the best selling being needles, glass tubes and electronic digitals。
In a community supermarket near ding fokang, journalists offered to buy thermometers, and the owner recommended a glass pipe kerosene thermometer. Journalists look at appearances marked with manufacturers, mc markings (licensing of measuring devices, etc.)。
"the glass pipe's cheap, it buys a lot. You need to buy electronics better." it says that the boss produces an electronic thermometer, which “can show the temperature, can see the date time, is multifunctional.” when asked about the temperature measurement, he calls it “accurate”。
Journalists purchased a glass pipe thermometer at the shop, a multi-purpose electronic thermometer and a pointer thermometer at the treasure shop. The reporter placed the three thermometers at the same location in his home and observed them after half an hour, and the temperatures shown in the three sections showed 21°c, 21. 5°c and 23. 5°c, respectively。
Experiment
What's the difference between these three thermometers? Thermometers were sent yesterday to the beijing school of clothing professional laboratory for testing experiments。
Experimental guidance: engineer hu junman, beijing school of clothing
Experimental operations: han xianxian, a graduate student at beijing clothing school
Experimental instruments: standard thermometers (symmetrical), test thermometers, refrigerators, thermostat dryers
Thermometers marking producer (or brand)
Second class mercury thermometer (moderate minus 0. 2) a/
Electronic digital thermometer b mantext
Pointer-type thermometer c shenzhen high gold products
Glass tube kerosene thermometer d beijing conway watch ltd
Note: the standard thermometer is the second class mercury thermometer, which is regularly calibrated by the laboratory. The glass tube thermometers are “red water” thermometers, and the market is dominated by kerosene thermometers and alcohol thermometers, which were tested as kerosene thermometers。
Rationale
In the four environments of indoors, outdoors, refrigerators, and hot dryer boxes, test samples are placed together with standard thermometers for 30 minutes to read and compare。
Data
Indoor (laboratory laboratory floor)
Thermometer result (°c) versus standard margin (°c)
A 19. 5 /
B 22 2. 5
C 21. 5 2
D 20 0. 5
Outdoor (laboratory floor)
Thermometer result (°c) versus standard margin (°c)
A11. 4 /
B 14. 9 3. 5
C 12. 5 1. 1
D 11. 8 0. 4
Refrigerator
Thermometer result (°c) versus standard margin (°c)
A 3. 9 /
B 5. 6 1. 7
C 4. 8 0. 9
D 3. 6 - 0. 3
Electro-hot hot dryer
Thermometer result (°c) versus standard margin (°c)
A30. 5 /
B 25 - 5. 5
C31. 1 0. 6
D 31 0. 5
The greatest error in the electron thermometer is concluded
Based on the results of the laboratory standard mercury thermometers in the four above scenarios:
Maximum: glass tube kerosene thermometer (d), error within 0. 5°c
Minimal: multifunctional digital thermometers (b), maximum difference of 5°c and slowest temperature change rate
The electron thermometer is not very accurate
According to an experimental guide to mr. Hu and the operator han, the mercury thermometer works by thermal expansion of mercury compared to the temperature. Mercury is a stable metal, enclosed in thermometers, and thermal inflation factors are constant. The electron thermometers, on the other hand, measure the temperature by testing the thermal dynamics of heat sensors。
In response to an error in the test results of the three thermometers in this trial, the operator, han, analysed that “thermal sensors of the electron thermometers have problems with zero-point drift and cold-end compensation, such as power voltage instability and the reduction of thermal power differentials, which can result in incorrect measurements and errors. So the electron thermometer, which is less precise, may be slightly less accurate." according to han, this type of electron thermometer is calibrated through a standard mercury thermometer, which also suggests that the mercury thermometer is more accurate。
Journalists enquired about the methods of measuring indoor temperature in residential heating (beijing city local standard db11/t-2010), in which technical requirements for measuring instruments show that the maximum allowable error of 0. 5°c in digital thermometers is shown。
With regard to why the error in the experiment was as high as 5. 5°c, han said that, because of the complexity of the construction of the digital thermometer and its time, calendar and so on, the heat sensor could not be exposed directly to the surrounding ambient temperature and the heat could be slow, so the test results would be incorrect。
The electron thermometer has no calibration protocol
This morning, journalists interviewed experts from the beijing academy of metrology and testing。
Experts indicated that there are various forms of thermometers available on the market, such as glass, transmission of data through sensors, but that there are currently no measurement and measurement protocols available for digital thermometers, resulting in temperature errors that cannot be judged in actual tests。
Vendor: corrected before release
This morning, journalists connected the manufacturer of thermometers, shenzhen, inc., and the beijing conway instrument limited, all of which stated that all thermometers were to be adjusted to the national corrective thermometer standards prior to their release。
“each thermometer needs to be calibrated according to the national marker before being released from the plant, and if it is not corrected, the results of the temperature measurements will certainly be inaccurate.” according to the person responsible for it。
At the time of the release, journalists had not contacted the manufacturer of the “mantext” electronic thermometer。
Doctor: temperature and cold
This morning, dr. Lee, who worked at a tri-acadet hospital, said that winter room temperature had an impact on the human body, especially on infants。
“if the thermometer is miscalculated, parents cannot control the room temperature suitable for the baby.” dr. Lee said that, in general, the choice of thermometers was more traditional and precise. The baby's not feeling well in the house, depending on how hot the room is, how hot it is and how cold the baby is. Zhou xianxiang
