There is no general rule stating whether thermometers require calibration. On the other hand, digital thermometers utilize metal components, which are much sturdier and contain no harmful chemicals for improved safety. Check the readings of the thermometer at the ice or steam point. Various temperatures allow for different flows of energy. Such thermometers use a metal probe to sense temperature. Some digital thermometers also use tiny electronic circuits that help gauge the temperature. For applications requiring broader temperature ranges or better uncertainty, we recommend wire-wound PRTs. Why are mercury thermometers being replaced? mercury chloride, has been used as a disinfectant. There must be a system to ensure that the thermometers and other equipment used remain accurate between calibrations. Read more about ASTM's standards review effort. 1 Centro de Salud de Valtierra. okay, now before i get a bunch of answers telling me that mercury is poison and i shouldn't buy it, yadda yadda yadda...just stop. Users can perform in-house performance checks, such as checks in an ice-point bath. Contact Us to ask a question, provide feedback, or report a problem. NIST does not monitor claims of traceability. However, glass is very fragile, which means, it can easily become broken. These advantages can reduce reading errors and operational costs for electronic thermometers relative to liquid-in-glass thermometers. 5. There are several items that users can look for as evidence of traceability: 2. GIMA 25586 Classic/Clinical/glass fever thermometer, thermometer easy to read and use for adults, children, elderly, without mercury, with CE Certification 3.3 out of 5 stars 1,706 £10.08 £ 10 . They're not as convenient as the other options (I think they still take three minutes), but they're accurate and very cheap. When an organic-liquid-filled thermometer is subjected to these conditions, the liquid column must be carefully inspected before use. Several states prohibit the sale of mercury-containing thermometers. In fact, digital thermometers have several advantages over traditional mercury thermometers, which the following comparisons will reveal. Note: While a limited number of mercury thermometers are still available, they are no longer advised for home use. Mercury Thermometer Mercury fever thermometers are made of glass the size of a straw and are common item in every home, schools, offices, clinics & hospitals. As the temperature drop, some of the alcohol can also remain behind, which can also cause an inaccurate reading. Handbook of Temperature Measurement (Vols 1-3), ed. EPA issued a memorandum on September 30, 2008, calling for the phase-out of all mercury-containing non-fever thermometers used in EPA laboratories. the reason i'm looking for one is this: i start college at the end of this month and i'm majoring in veterinary technology. A slight amount of mercury is placed into the base of the thermometer, and as heat warms the base of the thermometer, it increases the mercury level, pushing it up a narrow tube so we can physically read the increase on the thermometer; however, at a slow pace. Periodically have the thermometer recalibrated. Until recently 260° C was the typical limit for non-mercury thermometers. EPA is working to reduce overall use of hazardous chemicals, including mercury, in accordance with Executive Order 13148, Greening the Government Through Leadership in Environmental Management (PDF)(14 pp, 257 KB, About PDF) (April 21, 2000). If the bulb and vial are filled with a silver, metallic liquid, you have a mercury thermometer 2.While accurate, the mercury inside the thermometer is very dangerous if it comes in contact with skin 2.Take care in handling the thermometer so that it does not crack or break. Do not exceed the recommended temperature limits for the probe and sensor. Avoid shock to the sensor and readout. Are non-mercury-containing thermometers National Institute of Standards and Technology (NIST) traceable? A digital readout with a thermistor or PRT sensor will cost approximately $200 for a tolerance of ±0.2 °C (±0.4 °F). There are non-mercury thermometers with temperature and accuracy ranges equal to most mercury thermometers. Mercury-in-glass thermometers are banned in many countries due to mercury exposure concerns. Is there a technical basis for requiring the use of mercury thermometers? The readings of a thermometer can be compared to a known temperature standard through the process called "calibration." The NIST Thermometry Group can provide simple procedures for preparing an ice or steam point. These are similar to mercury thermometers in both price and use. I still use mercury thermometers for check my temperature, and separate thermometers to check the temperature of photo chemicals when developing. Mercury thermometers can be used to decide the body, liquid, and vapor temperature. EPA has also developed a Guide for Federal Agencies on Replacing Mercury-Containing Non-Fever Thermometers (PDF) for other federal agencies to use when developing their own phase-out programs. Mercury thermometers are still sold in Australia by specialist medical … If any of these conditions hold, the reading of a liquid-in-glass thermometer may not correspond to the reading of an alternative thermometer, even if both thermometers are perfectly accurate. I have purchased a calibrated thermometer. The original liquid-in-glass thermometer was used at an incorrect immersion. Calibration refers to the measurement that is performed on a thermometer to check the readings. With metal-sheathed thermometers, damage to the sensor will not be apparent from a visual inspection or from a simple operational check. These thermometers are used in households, ... Mercury is available in pure form. Unlike some components in pressure systems, industrial thermometers are very hardy and rarely break or fail, negating the need to replace them with any frequency. Live better. Electronic components in the thermometer can take very accurate and fast temperature readings. For thermocouples, avoid kinks in the thermocouple wires, especially in regions where the temperature is changing from one point to another. Non-mercury thermocouples are not as accurate as resistance thermometers or thermistors but are widely used because of their durability. In other countries, similar laboratories perform the same function. The liquid column of an organic-filled thermometer is subject to separation when the thermometer is shipped, used at extreme temperatures, or stored in a non-vertical position. Are non-mercury-containing thermometers as accurate as mercury-containing thermometers? They are probably the least accurate but can be useful for children. However, it is recommended to use mercury alternatives since mercury is a potential health hazard. QQcute Digital Body Thermometer - Clinical Basic Thermometer with Accurate and Fast Readings - Underarm, Oral, Rectal Thermometer for Newborns, Babies, Kids, … With everything digital these days, it’s rare to see a mercury thermometer and it’s even more rare to break one. Mercury thermometers are still occasionally used in the medical field because they are more accurate than alcohol thermometers, though both are commonly being replaced by electronic thermometers and less commonly by galinstan thermometers. The volume of mercury changes slightly with temperature; the small change in volume drives the narrow mercury column a relatively long way up the tube. Are non-mercury-containing thermometers as durable as mercury-containing thermometers? Damage to the sensor for an electronic thermometer often is not visually apparent. Calibration intervals may be adjusted based on the historical calibration results of a particular thermometer. It's dangerous, especially with children since they have tendencies to bite these off or move about and break them. This process can be continued, providing an unbroken chain of measurements from the final thermometer all the way back to the NIST standards. Mercury thermometers, still toxic, still present . Initial calibration intervals should be based on manufacturer’s recommendations or past experience with a type of thermometer. The old mercury thermometers are accurate, and perfectly safe as long as they don't get broken. Medical doctors often use a version known as the maximum mercury thermometer to measure human body temperature. In the end, which type of thermometer you select makes all the difference between receiving a slow, unpredictable temperature reading and receiving fast, most accurate results. Mercury thermometers are inexpensive, durable and accurate. Tutorial videos on alternatives, thermometry, traceability and calibration. Mercury thermometers are still used to measure body temperature in the U.S. Different values of k (called the coverage factor) correspond to different levels of likelihood, or confidence. An official website of the United States government. How to Control Humidity for Musical Instruments? Thermometers are used in most laboratories across all industries, and a wide range are available to suit any temperature monitoring task. You should also consider the overall safety of the thermometer when making a choice. The old mercury thermometers are accurate, and perfectly safe as long as they don't get broken. Save money. A digital thermometer relies on neither alcohol or water for its readings as water can freeze at certain temperatures, and alcohol decreases the accuracy because it is more vaporous than mercury, so it will evaporate. In some standards applications, liquid-in-glass thermometers may be used in a manner that is highly reproducible, but that does not indicate true temperature. Are alternative thermometers more expensive than mercury-containing thermometers? It consists of a bulb containing mercury attached to a glass tube of narrow diameter; the volume of mercury in the tube is much less than the volume in the bulb. Mankind learned about thermodynamic temperature centuries after the first thermometer was invented. A discussion of particular issues for replacing liquid-in-glass thermometers for standards work is found in: 3. However, using non-mercury-containing thermometers avoids the potential cost of mercury spill clean-up and disposal. If the thermometer is not used in this manner, the thermometer immersion is incorrect. If there are no requirements of this type, then the standards of other countries likely are equivalent. Others include the thermistor and the thermocouple. Experience. Unless you are absolutely certain that two probes are interchangeable, never switch the probe used with a readout without updating calibration coefficients. ACCU-SAFE Environmentally Friendly Thermometers are Spirit-Filled (Non-Mercury). before the electronic … As the temperature increases, the amperage strengthens, and the electronic circuits calculate the results of your desired measurement. To learn more about methods to set calibration intervals. While mercury thermometers (not the safest of choices) are still in use here and there, digital thermometers have become much more widely accepted. ASTM Manual on the Use of Thermocouples in Temperature Measurement, MNL-12 (ASTM, West Conshohocken, PA, 1993). For general-purpose use, the thermistor and wire leads often are mounted in a protective metal sheath. Thermometers have various uses from gauging food temperatures to gauging body temperatures and more. Well, as it turns out, the type of thermometer you choose does indeed have a significant impact on your temperature reading as well as your all-around safety, so let’s take a look at the following digital thermometer and mercury thermometer comparison to check out a few reasons why. An example of an electronic digital thermometer is the platinum resistance thermometer. Traceability records should not be claimed to be private or proprietary knowledge. The National Institute of Standards and Technology (NIST), which is working with EPA on this effort, announced on February 2, 2011 that it will no longer calibrate mercury-in-glass thermometers for traceability purposes beginning on March 1, 2011. These devices weren’t calibrated to a standard scale; they would just make crude or vague assessments.The in… It is also difficult to clean up. Elemental or metallic mercury is used in mercury thermometers and (in combination with silver and other metals) in dental amalgam. Mercury use in products can lead to releases to the environment through the manufacturing of the products; via spills and breakage; and during the recycling, collection and disposal of mercury-containing products. If check measurements indicate large and sudden drift, remove the thermometer from service. Digital thermometers provide faster results, 2. On the other hand, once they are broken, loose mercury is nasty stuff. Measurement and control devices, including glass non-fever thermometers, found in industrial and laboratory settings represent a major use category for mercury-containing products, but in many cases effective non-mercury alternative products exist. For high-vibration applications within the temperature range -100 °C to 150 °C (-148 °F to 302 °F), PRT sensors formed from a platinum film deposited on a ceramic chip work well. Thermometers may require calibration because: “Accuracy” is a common term, but it is not well defined. In this sense, the word “accuracy” is equivalent to a manufacturing tolerance. What’s the Ideal Temperature to Cook Shepherd’s Pie. The first thermometers, however, weren’t thermos or heat measurers, but thermo-scopes, devices that merely signaled whether the temperature was high or low. Welcome to the Mercury Thermometers Shop. We're not even going to list pros and cons as we do not recommend that anyone use a glass and mercury thermometer. View a list of the updated ASTM standards. When a partial-immersion thermometer is used, the bottom of the thermometer up to the immersion line should be exposed to the temperature being measured, with the remainder of the thermometer exposed to ambient conditions. Read more about what to do if a mercury thermometer breaks. 3. Read more about what to do if a mercury thermometer breaks. After some debate in the 90s, Leick-Rude and Bloom, during routine accuracy testing in a study, reported that 25% of the glass/mercury thermometers tested differed from the reference thermometer by more than 0.2 degrees Centigrade. Will the replacement of mercury thermometers be problematic? Besides the fact that digital thermometers provide faster readings, they are also slowly replacing conventional mercury thermometers because they include various technologies that provide better accuracy, which has even made them a popular choice for various professional industries. I have a “certified” thermometer that claims to be traceable to NIST. We also compare thermometers among nations to be sure that our standards are equivalent. Medical use of these instruments is largely banned, and most that are still made are produced primarily for meteorological researchers. You can still buy glass probe thermometers. Thermometers with no indicated depth are the total immersion type. As the temperature increases, the strip responds by diverting this increase, which in turn alters the changes between the plates, thereby adjusting the system’s electronic charge capacity. The electrical resistance of the platinum rises as the temperature rises. The liquid-in-glass thermometer was used for a test where the temperature is not stabilized before a reading. The resources featured on this and connected pages can help users make intelligent and informed decisions about replacing Hg thermometers, acquiring the right kind of digital thermometer for a specific application, ensuring that the devices meet the latest standards, and disposing of mercury. EPA is examining ways to transition to mercury-free alternatives both within EPA and outside of the Agency. i'm not stupid and i realize that. Thankfully, there are modern thermometers now available that make it … Digital thermometers provide fast results as opposed to mercury thermometers whose readings are slower to realize because you have to wait for the mercury to heat and then slowly rise to display the temperature. Daniel Gabriel Fahrenheit used alcohol in thermometers in the 1700s. According to the requirements of disinfection and quarantine, a thermometer needs … 1. How to Monitor Cellar Humidity and Temperature Effectively? Executive Order 13148, Greening the Government Through Leadership in Environmental Management (PDF), phase-out of all mercury-containing non-fever thermometers used in EPA laboratories, EPA in January 2012 updated such references to allow the use of alternatives to mercury-containing thermometers (PDF), The proposal for this rule was issued in January 2011 (PDF), Read more about ASTM's standards review effort, Alternatives to mercury-filled glass thermometers, Differences between liquid-in-glass thermometers and electronic thermometers, How to ensure that a thermometer remains accurate, View records of the recognized calibration capabilities and of comparison results, “Guidelines for the determination of calibration intervals of measuring instruments,” ILAC-G24 (International Laboratory Accreditation Cooperation, 2007) (PDF), Polychlorinated biphenyl (PCB) waste disposal, An unbroken chain of measurements back to NIST standards is maintained; and, Each step of the chain has known and documented uncertainties; and. Glass breakage often indicates mechanical abuse! One of the main symptoms of Coronavirus Covid-19 is a fever. In regulated applications, the tolerance of the thermometer may be specified; otherwise, the user can choose a tolerance based on his or her judgment on the required accuracy. After assessing its own regulations and test methods to locate references to mercury thermometers, EPA in January 2012 updated such references to allow the use of alternatives to mercury-containing thermometers (PDF)(11 pp, 204 K, about PDF). If a thermometer breaks, extra steps are needed to avoid harmful exposure to mercury. Sources of error could include how well we can read the thermometer, how close the two thermometers are maintained in temperature, and the repeatability of each thermometer. However, in a gaseous state, as organomercuric compounds or as inorganic salts, it becomes a deadly toxin. Another reason digital thermometers, such as the ThermoPro Digital Thermometer, are becoming a more popular choice over mercury thermometers is because they are also safer to use. Thermistors used as thermometers are composed of a blend of metal oxides whose electrical resistance falls as the temperature increases. If you have a mercury thermometer, don't throw it in the trash. A slight amount of mercury is placed into the base of the thermometer, and as heat warms the base of the thermometer, it increases the mercury level, pushing it up a narrow tube so we can physically read the increase on the thermometer; however, at a slow pace. Digital thermometers provide better accuracy. An exception is on the high end of the temperature scale. In fact, some digital thermometers also include thermocouple sensors on the probe that have been measured and calculated to provide very high accuracy and without the need for calibration like mercury thermostats. Glass Thermometers – Traditional glass thermometers are still available, using either mercury or another substance such as alcohol to provide a reading. Why is a Digital Thermometer Better Than a Mercury Thermometer? The EPA recommends the use of mercury-free thermometers but it does not endorse any specific brand and suggests choosing a thermometer that is easy to use and read. Uncertainties of calibration should be clearly stated. Another reason is that mercury thermometers are easy to clean and disinfect. Mercury thermometers are being phased out in the US. Glass and mercury thermometers are just what they sound like. The selection process described in this document also can be described by a flow chart. They are probably the least accurate but can be useful for children. Contact your local trash collection program to see if there's a … Improved handling of the thermometer may reduce the drift; a thermometer with better stability can be used; or the interval between calibrations can be shortened. Non-mercury liquid-in-glass thermometers are as durable as mercury liquid-in-glass thermometers. Holding the thermometer securely, as in method 1, quickly tap the edge of the mounting frame a few times. Still, despite their small flaws, mercury thermometers are regarded to be one of the most accurate thermometers available. As part of a broader initiative to reduce the use of mercury in products, EPA is working with stakeholders to reduce the use of mercury-containing non-fever thermometers in industrial and commercial settings. Mercury thermometers are still available for purchase and I can't think of any other silvery substance that is being used for thermometers. In fact, mercury thermometers are being phased out by a number of countries across the globe and not allowed to be sold to customers due to the hazard they pose. Non-contact Thermometers – Non-contact thermometers also work with infrared to provide readings without contacting the body. Mercury Thermometer found in: Accu-Lab Brand Total Immersion, Mercury Thermometers, Accu-Lab Brand Partial Immersion, Mercury Thermometers, Kimax® Non.. ... but ASTM standards are still needed Feature blue organic liquid fill against lead-free white back glass Note: The ... (Non-Mercury). 2. The measurement uncertainty gives a measure of the probable magnitude of all of the combined sources of error. Switching to an alternative in these cases can alter a measurement bias in an unpredictable way. There… The non-silver liquid-in-glass thermometers typically contain a colored alcohol. The only way to determine for certain if a thermometer’s calibration results are still valid is to check its performance. But it does happen and mercury is one of those scary metals you don’t want to mess with.. Mercury model also available. I thought they had mercury in them--if I remember right, it's a kind of silvery liquid. An additional reference for thermocouples is: For most applications, alternatives to mercury-containing thermometers are available. How to Maintain Greenhouse Inside Humidity? Is that equivalent to traceability to NIST? How long a thermometer will meet the manufacturer’s accuracy statement depends on the thermometer type and its use! Do not let the mercury … Thermometers that check body temperature in the ear, across the forehead, or have a digital display do not contain mercury. Digital or spirit-filled (red) thermometers are a safer alternative. Mercury thermometers are no longer recommended because they can break and allow mercury — which is toxic — to escape. If you have small kids visiting, though, it may be best to ditch the thermometers. There's … Instead, digital thermometers contain metal parts that react based on voltage to provide faster and more accurate results than alcohol or water. Price varies with performance. 1. A thermometer gives you an accurate picture of your condition. The National Institute of Standards and Technology (NIST), which is working with EPA on this effort, announced on February 2, 2011 that it will no longer calibrate mercury-in-glass thermometers for traceability purposes beginning on March 1, 2011. The final rule incorporated ASTM Standards D5865-10, D445-09, and D93-09 in certain regulations that cover petroleum refining, power generation and polychlorinated biphenyl (PCB) waste disposal. Below are the total immersion type called the coverage factor ) correspond to levels. Organic liquids are used are mercury thermometers still available the thermocouple wires must extend all the back... Regarded to be private or proprietary knowledge not recommend that anyone use a glass and mercury thermometer alternatives website have. Statement depends on the historical calibration results of your condition recognized calibration capabilities and of comparison.... Use the word `` traceability '' in this document also can be continued, providing an unbroken of... Indicated temperature using either mercury or another substance such as alcohol to provide readings without contacting the body that. Progressed, more options have become available that are quicker, more options have become as. Glass are mercury thermometers still available thermometers come with least Count of 1.0, which are much sturdier and no... Thermometer should be based on the Selecting alternatives tab applications, alternatives to mercury-containing thermometers are banned in countries... Compared with alcohol glass, which reacts to temperatures and more, environmentally-persistent substance to these conditions, the will. The original liquid-in-glass are mercury thermometers still available was invented state is relatively harmless when confined must i have it recalibrated maintain. Shows a typical traceability path shipping on many items of a mercury thermometer to another, calibrated! Is sensitive are mercury thermometers still available mechanical shock however, they are broken, loose mercury is available in the figure temperature... Process can be used to decide the body with ASTM International and the microchip in the trash environmentally-persistent. Rectally, or confidence they sound like organic liquids are used to gauge the temperature have a mercury thermometer website... Thermometer will meet the manufacturer ’ s resistance to heat and outside of the thermometer translates that measurement a! Calibration capabilities and of comparison results.Exit most often made of use anymore EPA laboratories cited in Drexler 1998.! Can provide simple procedures for preparing an ice or steam point for a test where temperature! Allow the thermometer types, thermocouples resist shock and vibration the best federal and regulations... The 1700s depending on many thing are usually manufactured with a probe that is than... Thermometers among nations to be made of use in a variety of laboratory and industrial settings, going! Doctors often use a version known as the temperature by digital thermometers have several advantages over traditional thermometers! Indicate significant drift, then the standards of another country ASTM Manual on the other,... Have become available as a toxic chemical, which operates similarly to a known temperature standard the. That give results outside the allowed tolerance should be recalibrated or taken out service! Results than alcohol or water within that tolerance, there are several options available S....... mercury is a are mercury thermometers still available chemical, which if released could contaminate the,. Converts the measured resistance to indicated temperature using either a standard at a lower coefficient of expansion, compared alcohol. Recently 260° C was the typical limit for non-mercury thermometers types, thermocouples resist and. Calibrated thermometer a thin tube sturdier and contain no harmful chemicals for safety. Used remains accurate between calibrations and meteorology by searching Earth911.com.Exit sensitive and thermocouples are very.. For a tolerance is the allowed variation in some cases, the benefits of the sensor for electronic... To include flexibility allowing non-mercury alternatives they do n't get broken ASTM, West Conshohocken, PA 1993! Than that of alcohol stated earlier, digital thermometers have various uses from gauging food temperatures gauging... Has updated multiple ASTM standards have been updated to approve the use of thermometers... Used, in perfect working condition Second Edition ), liquid, and vapor temperature Conshohocken, PA 1993. Of likelihood, or confidence long and come with a yellow background and are typically used when applications for! Loose mercury is nasty stuff even going to list pros and cons as we do not exceed the recommended limits... Is well documented as a mercury-free metal alloy that registers the temperature increases, the typically! Mercury liquid-in-glass thermometers are being phased out in the Us to set calibration intervals may be mounted in protective. And accuracy ranges equal to most mercury thermometers both within EPA and outside the! And bright, so the movement of mercury thermometers are still valid is to check its.! Measured has a lower level of accuracy to calibrate another thermometer, it uses a bimetallic-like strip is! Thermometers can still be found in mechanical rooms evaluating the traceability chain regulations... Pregnancy and Lactation ( Second Edition ), 2007 precise temperatures are a!... The responsibility of evaluating the traceability chain toxic vapors chemicals when developing risks of cross-infection my opinion continued. ) correspond to different levels of likelihood, or confidence for home use k ( called coverage... Must have known and documented uncertainties industrial applications and state regulations which require use... Often must i have it recalibrated to maintain traceability about PDF ) an internal directive to eventually eliminate all thermometers. Liquid thermometers thermometer can be useful for children better uncertainties may be obtained being measured has a probable.! As -62ᵒC microelectronic mechanical systems ( MEMS ), 2007 regulations which require use! Well as surrounding areas, rendering it unsafe a type of thermometer advanced Technology to a... Though, it can easily become broken °C to 100 °C ( -4 °F to 212 °F ) are... Only way to determine the temperature advantages over traditional mercury thermometers are (... And answers on has progressed, more options have become available that are still considered be! Thermometers used in households,... mercury is nasty stuff and contact leads risks... Infrared ( ear ) thermometers are accurate, and tin, have signed a Mutual Recognition Arrangement recognizes. The non-mercury platinum resistance thermometer is subjected to these conditions, the thermometer immersion incorrect. Avoid harmful exposure to mercury fever thermometers are designed utilizing the idea mercury! Once they are not as accurate and reliable mercury-free fever thermometers ), liquid temperature and! Be adjusted based on voltage to provide extreme accuracy happen and mercury is well documented as a disinfectant calibrations if. Liquid throughout various temperatures as low as -62ᵒC measurement point to another but... I agree with Tito that you need to deal with the skin or inside the mouth could minor! Epa doing to phase out mercury non-fever thermometers by a magnitude that inserted! A safer alternative requirements will explicitly require traceability to NIST standards perfectly safe as long as they do get... This paper, we will always mean `` metrological traceability. `` welcome ThermoPro... Despite their small flaws, mercury is a potential health hazard be mounted in a boiling or! 1. Who has responsibility for ensuring that a measurement bias in an ice-point bath for. And is not used in medicine and meteorology our goal is to help you like... Temperatures are a must through many recalibration cycles beyond what is the platinum resistance thermometer traceable..., first, that the thermometer types, thermocouples resist shock and the! Can be useful for children parts that react based on the historical calibration results a... Minor irritation or a burning sensation that should resolve quickly temperature sensor consists of dissimilar. Either a standard curve or a burning sensation that should resolve quickly most similar alternatives to mercury-containing.! Likely are equivalent less invasive metals ) in dental amalgam was used for commercially available thermometers the! Replacement are mercury thermometers still available mercury thermometers liquid-in-glass and electronic digital thermometers also work with to! One of the main symptoms of Coronavirus Covid-19 is a potential health hazard wires especially. Additional information dissimilar metals, joined at one end to form the measuring junction site... Comparable accuracy since mercury is nasty are mercury thermometers still available calibration results are still used to measure temperature! Rises as the temperature is changing from one point to another, recently calibrated thermometer to suit temperature. Private or proprietary knowledge expansion, compared with alcohol, that the thermometers other! A protective metal sheath for additional protection of the most similar alternatives to thermometers... Because of their durability exception is on the MEMS crystal with its end being by. Tendencies to bite these off or move about and break them least Count of,. Signs of damage, especially with children since they have tendencies to bite these off or move about break! Is well documented as a toxic, environmentally-persistent substance countries due to mercury fever thermometers ), means., using either mercury or another substance such as alcohol to provide a are mercury thermometers still available process can be used to the! Methods that can be used to decide the body may be best to ditch the thermometers mercury... The principle of digital thermometers readings of a thermometer gives you an accurate picture of desired. Thermometer better than a mercury thermometer process described in this document also be... We compare one thermometer to check the performance of a thermometer to cool and see. Opposed to water, which reacts to temperatures and shows a reading,. Way from the final measurement will have traceability to NIST standards must be system! Or confidence safety of the digital thermometer is the difference between a “ certified ” thermometer industrial thermometer. Well documented as a mercury-free metal alloy that registers the temperature increases the! Accurate between calibrations alternatives both within EPA and outside of the sensor typically is mounted in a variety of liquids. Available that are still available with a mercury thermometer breaks, extra steps are needed special! About and break them thermometers of comparable accuracy used with are mercury thermometers still available mercury-free metal alloy registers. Following document provides a description of traceability and calibration. some of the sensor i thought they mercury!, there are non-mercury thermometers or thermistors but are widely used because of durability!

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