precautions while using laboratory thermometers

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Precautions while using Laboratory Thermometers

The precautions to be observed while reading a laboratory thermometer.
11. Mercury Spill Cleanup
Personnel responsible for cleaning up a mercury spill, according to Princeton, should wear protective clothing, gloves and goggles, and use index cards to sweep the contaminated material into a sealable jar. Never use a vacuum cleaner or sink. Label the jar, and deliver it to a hazardous waste facility.
12. Alcohal thermometers
Mercury thermometers, used in some science labs, require special safety precautions. Alcohol thermometers, though less dangerous, should still be handled carefully to avoid broken glass. Secondary thermometers are most widely used because of their convenience. Also, they are often much more sensitive than primary ones. For secondary thermometers knowledge of the measured property is not sufficient to allow direct calculation of temperature. They have to be calibrated against a primary thermometer at least at one temperature or at a number of fixed temperatures. Such fixed points, for example, triple points and superconducting transitions, occur reproducibly at the same temperature.
13. Uses at home clinics and hospitals
Thermometers are used to measure the temperature of the human body, at home, clinics and hospitals. When performing this procedure, hold your hand less than 1 inch from the stopper to avoid exerting torque on the thermometer. Thermometers can be calibrated either by comparing them with other calibrated thermometers or by checking them against known fixed points on the temperature scale. The best known of these fixed points are the melting and boiling points of pure water.
14. Safety
Lab thermometer safety depends on the type of thermometer: broken alcohol thermometers and other nonmercury thermometers only require the same cleanup as any other broken glass, according to University of Illinois at Chicago. A broken mercury thermometer requires special cleaning procedures.
15. Points to kept in Mind while using a thermometer
The thermometer should be protected from sudden changes of temperature. Never wash a hot thermometer in cold water or put a cold thermometer in a hot bath. For correct reading of temperature see that the thermometer is vertically and your eyes are exactly in line with the mercury level. Mercury on heating expands. Even a small expansion of mercury in the bulb of the thermometer causes a considerable rise in the capillary tube.
16. Precautions while using a clinical thermometer
While putting the clinical thermometer in the mouth do not press it with your teeth. Hold it simply with the help of your lips. A slight pressure by teeth may result in the breaking of the thermometer bulb and release the mercury in the bulb. Mercury is poisonous. In case of children, the thermometer should not be put in their mouth. It should be kept under armpit. Half a degree is added to the reading in the thermometer. This gives the body temperature of the patient (child), The thermometer should be kept vertical. The eyes should be exactly in line with the mercury level.
17. HowLaboratory Thermometers work
The way a laboratory thermometer works depends upon its type. They are generally a liquidinglass device, a bimetallic strip, an electronic thermistor thermometer, or infrared (IR) device. Many empirical thermometers rely on the constitutive relation between pressure, volume and temperature of their thermometric material. For example, mercury expands when heated.
18. Selection Criteria for Laboratory Thermometers
The GlobalSpec SpecSearch database allows industrial buys to select laboratory thermometers by type, display options, operating environment, and specialty features. Thermometers may be described as empirical or absolute. Absolute thermometers are calibrated numerically by the thermodynamic absolute temperature scale. Empirical thermometers are not in general necessarily in exact agreement with absolute thermometers as to their numerical scale readings, but to qualify as thermometers at all they must agree with absolute thermometers and with each other in the following way: given any two bodies isolated in their separate respective thermodynamic equilibrium states, all thermometers agree as to which of the two has the higher temperature, or that the two have equal temperatures.
19. Liquid in glassthermometers
Liquidinglassthermometers are made of sealed glass and contain a fluid, usuallymercuryorred alcohol, whose volume changes relative to its temperature. The liquid expands as the temperature rises, rising in the tube and indicating the temperature.
20. Bimetallic stripthermometers
Bimetallic stripthermometers include two different metals that are bonded together and expand at different rates as they warm up. Since the two metals expand to different lengths, the bimetallic strip is forced to bend or curl towards the side with a lower coefficient of thermal expansion. The movement of the strip is used to deflect a pointer over a calibrated scale which then indicate temperature to the user. Often, long bimetallic strips are wound into a coil and used with a dial.

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