Mercury thermometers are now being replaced by digital thermometers. 5. Mercury thermometers can be used to determine body, liquid, and vapor temperature. More importantly, the temperature measurement is only a reference, whether to administer medicine to children or take them to the hospital depends on the judgment of … Mercury has been frequently used in thermometers because it remains in liquid form throughout a wide range of temperatures: -37.89 degrees Fahrenheit to 674.06 degrees Fahrenheit. Will the replacement of mercury thermometers be problematic? Thermometers that check body temperature in the ear, across the forehead, or have a digital display do not contain mercury. Daniel Gabriel Fahrenheit used alcohol in thermometers in the 1700s. Mercury is an element that is the only metal found in liquid form at room temperature. Will the replacement of mercury thermometers be problematic? When used correctly, the digital thermometer is accurate enough to meet daily needs and safer than the mercury thermometer. In a mercury thermometer, a glass tube is filled with mercury and a usual temperature scale is marked on the tube. Mercury thermometers cannot measure temperatures below this point. Thermometers that check body temperature in the ear, across the forehead, or have a digital display do not contain mercury. The alternative to the mercury thermometer is the digital thermometer, which measures temperature by monitoring changes in electrical properties voltage and resistance of metals inside the device. People tend to associate mercury with its silvery liquid form - perhaps found in old thermometers. A mercury thermometer is a tool used to measure temperature. It can be found in meteorological equipment like thermometers and barometers. Ethanol is cheaper and safer than mercury and can be used as low as -80˚C. All rights reserved. While mercury thermometers are safe when used correctly, they pose significant risks when they break or if disposed of improperly. Other Corrections 1 The Thermometer Correction. Historically, mercury thermometers have been used for nearly all temperature measurements because of their accuracy and low cost. Mercury thermometers can be used to decide the body, liquid, and vapor temperature. What is the primary reason why liquid mercury (Hg) has been commonly used in thermometers for more than a century? ©Pxhere. © copyright 2020 QS Study. h) Mercury expands a lot with temperature. It will not enlarge when it solidifies, therefore, it doesn’t fracture the glass tube of the thermometer. However, they present many safety and environmental hazards. When used correctly, the digital thermometer is accurate enough to meet daily needs and safer than the mercury thermometer. So mercury level indicates the temperature as quickly as possible and accurately. The ethanol version is the most widely used due to the low cost and relatively low hazard posed by the liquid in case of breakage. Alcohol thermometers are considered much safer than the once popular mercury thermometers, but they are considered slightly less durable because the alcohol evaporates from the thermometer over time. g) Mercury is not an expensive metal. With changes in temperature, the mercury expands and contracts and the temperature can be read from the scale. For most applications, alternatives to mercury-containing thermometers are available. Modern thermometers are calibrated in standard temperature units such as Fahrenheit (used in the United States) or Celsius (used in Canada), or Kelvin (used mostly by scientists). Thermocouples are among the most widely used industrial thermometers. Thermometers containing mercury can be easily identified by the colour of the material in the bulb. Digital thermometers work by using heat sensors that determine body temperature. Mercury may be found in fever, basal, scientific, industrial and cooking thermometers. Several states prohibit the sale of mercury-containing thermometers. You might remember it best from its use in glass thermometers. The ethanol version is the most widely used due to the low cost and relatively low hazard posed by the liquid in case of breakage. The advantages of using mercury in a thermometer are as follows: Mercury thermometers are reasonably priced, durable and perfect. The increase of mercury is steady or linear to the changes of the heat, except for actual high temperature. Many older thermometers contained mercury. Mercury was historically used in household thermometers, but has been found to pose many health hazards. The alcohol thermometer or spirit thermometer is an alternative to the mercury-in-glass thermometer and has similar functions. In a mercury or alcohol thermometer, the liquid expands as it is heated and contracts when it is cooled, so the length of the liquid column is longer or shorter depending on the temperature. Historically, mercury thermometers have been used for nearly all temperature measurements because of their accuracy and low cost. Mercury is a good conductor of heat. Its stage indicates the temperature as rapidly as potential and perfectly. Expansion of mercury is uniform along the whole range of temperature. Hence, the slightest change in temperature is notable when it's used in a thermometer. The thermometer usually has a small reserve of liquid mercury in … Mercury expands as the temperature increases, thus raising the reading, while decreasing temperatures contract the mercury, lowering the reading. These thermometers are used in households, laboratory experiments, and industrial applications. However, it freezes at – 39 Celsius, so Mercury cannot be used below this temperature. Mercury is commonly used in barometers because its high density means the height of the column can be a reasonable size to measure atmospheric pressure. So it can move freely inside the capillary glass tube. Mercury is less volatile. Thermocouples are among the most widely used industrial thermometers. However, it freezes at – 39 Celsius, so Mercury cannot be used below this temperature. Mercury expands as the temperature increases, thus raising the reading, while decreasing temperatures contract the mercury, lowering the reading. Infrared (ear) thermometers may be used as an alternative to mercury fever thermometers. It comes in a few forms. Their use is gradually more being restricted to industrial and technical applications, as safety and environmental issues are demanding stricter laws on the removal of products containing mercury. The Times of India News App for Latest Sunday Times News, Copyright © 2021 Bennett, Coleman & Co. Ltd. All rights reserved. People tend to associate mercury with its silvery liquid form - perhaps found in old thermometers. The alternative to the mercury thermometer is the digital thermometer, which measures temperature by monitoring changes in electrical properties voltage and resistance of metals inside the device. When two bodies touch, their temperature adjusts, which means that the colder gets warmer, the warmer gets colder. The first thermometers, however, weren’t thermos or heat measurers, but thermo-scopes, devices that merely signaled whether the temperature was high or low. That is why mercury is used in thermometers. f) Mercury looks nice and shiny g) Mercury is not an expensive metal h) Mercury expands a lot with temperature i) Mercury has very high density compared to other liquids j) Mercury has a low latent heat for evaporation 6. Why Mercury Is Used In The Thermometer The role of a thermometer is an important one, and when used it home it can be the one diagnostic tool that tells us whether we’re sick or not. Mercury is well documented as a toxic, environmentally-persistent substance. The mercury is the red substance in the thermometer that rises when you put it in your mouth. Explain Raise of Temperature and Internal Enerty of Body, Establishing a Relation Among different Scales of Temperature, Explain Effect of Pressure on Boiling Point, Crab armies can be a key issue in coral wall preservation, Beaches cannot be extinct if sea levels continue to rise, Autonomous “Smellicopter” Drone Can Seek Out Scents with Live Moth Antennae, Scientists are finally studying why some of you don’t overturn your regulator, The vast wetlands of Els Eels are the most recorded at the bottom of the ocean. Broken mercury-filled thermometers … Continued A thermometer is a device that measures temperature or a temperature gradient (the degree of hotness or coldness of an object). The other wire is can move along a threaded rod. It has a high electrical conductivity and it expands and contracts evenly with changes in temperature. i) Mercury has very high density compared to other liquids. There are a number of different model types, sizes, and specifications, but the general operating principle is about the same in all cases. Mercury, for instance, becomes a solid at -38.83 degrees Celsius (-37.89 degrees Fahrenheit). Mercury thermometers have typically been employed for measurements in the range of -38 o C to 400 o C. Similar liquid-in-glass designs employing an organic fluid can have a range of -196 o C to 150 o C, depending on the fluid properties. It has a high electrical conductivity and it expands and contracts evenly with changes in temperature. The increase of mercury is steady or linear to the changes of the heat, except for actual high temperature. Somewhere in the middle is mercury, which stays in a liquid state until its temperature drops to -40°. Mercury is the only one in liquid state at room temperature. Elemental (metallic) mercury is a shiny, silver-colored liquid products, including lots of things used in schools. Thermometer | Why is mercury used in thermometer | precautions using thermometer | PB Learning Hub Mercury boils at 357°C, so, it can, therefore, be used to measure higher temperatures. New electronic thermometers and those that use a red dye and alcohol mixture are much easier to read and safer to use. The key thing with thermometers is that they must be accurate and also be able to detect a change in temperature to the smallest degree, and that’s why mercury was first used. Metallic mercury is toxic, and also expensive. Imagine two thin wires inside the capillary of your thermometer. Glass thermometers can break and cause the person injury, and some contain mercury, which is poisonous; ones containing mercury, in particular, are no longer recommended. The melting point of water is 0 o c but when you see mercury freezing point (melting point) -38.83 o c and the boiling point of the mercury is 356.73 o c. The boiling point of water is 100 o c. So based on this criteria the mercury is having the temperature reading capacity compared to water. Several states prohibit the sale of mercury-containing thermometers. However, their use is increasingly being restricted to industrial and scientific applications, as safety and environmental issues are demanding stricter laws on the disposal of products containing mercury. However, it freezes at – 39 Celsius, so Mercury cannot be used below this temperature. Mercury Hazards Mercury has been used in the measurement of atmospheric pressures and temperatures since the mid 1600s. Also, it has a shiny appearance and doesn't stick to the glass surface of glass. Therefore, initially, thermometers defined temperatures. Why are mercury thermometers being replaced? Laboratories are often dependent upon the ability to measure temperatures and pressures. Relationship Pitfalls And How To Avoid Them, 4 healthy diet tips to follow in the winters, 5 Traditional Foods to include in Lohri ki thaali, Samsung Galaxy Tab, HUAWEI MediaPad and Other 4G Tablets That Are Worth Considering, Green coffee for weight loss: Instant coffee packs to manage your weight, Terms of Use and Grievance Redressal Policy. 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. Dangers of Mercury Mercury is a very dense element that is the only metal to exist as a liquid at room temperature. Why is mercury used in thermometers despite being the poorest conductor of heat? This total includes thermostats used in residences, businesses, and industrial settings, including thermostats sold as stand-alone units … Photo by Matteo Fusco on Unsplash. These non-mercury fever thermometers are just as good as mercury thermometers and much safer. 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. Mercury thermometers will become a thing of the past in hospitals within the next few years if trends favouring alternative devices continue. Most metals are good conductors of heat and they are solids at room temperature. Why is mercury dangerous? 6. Mercury does not damp glass, this leads to an erroneous reading when the thread is falling. Mankind learned about thermodynamic temperature centuries after the first thermometer was invented. Mercury is a metal found naturally in the environment. However, ethanol boils at 78°C (172.4°F), which means its upper limit is much lower than mercury thermometers. Mercury-in-glass thermometers are less used in the 21st century as preference is shifted to other types of thermometers, such as digital, alcohol-filled and organic-based thermometers. Mercury's Use: Despite mercury being toxic to humans in its natural form, it has a variety of everyday uses. Today, mercury is used for the manufacture of industrial chemicals and for electrical and electronic applications. Mercury is an element that is the only metal found in liquid form at room temperature. In addition to the answer and the comment given, the use of mercury in thermometers had another advantage frequently used in the lab: Mercury, as a metal, has a high electrical conductivity. These non-mercury fever thermometers are just as good as mercury thermometers and much safer. With changes in temperature, the mercury expands and contracts, and the temperature can be read from the scale. Mercury does not stick to the glass surface. Mercury is the only one in liquid state at room temperature. It also has a high boiling point which makes it very suitable to measure higher temperatures. They expand and contract depending on the pressure or temeperature of their environment. Table 1 presents the total amount of mercury contained in mercury thermostats sold in the U.S. in years 2001, 2004, and 2007. The mercury-in-glass or mercury thermometer was invented by physicist Daniel Gabriel Fahrenheit in Amsterdam (1714). This means that it reacts quickly to changes in temperature. It's used in thermometers because it has high coefficient of expansion. Mercury has a … “A metal is full of bonds between the atoms that make it up,” explains Carter. Red dye is used to color the clear alcohol so that someone is able to easily read the thermometer. Mercury has been replaced largely by alcohol for use in thermometers. for a small change of temperature, the expansion of mercury is quite large. Actually, we try to avoid it these days. The boiling point of water is 100oc. Digital or spirit-filled (red) thermometers are a safer alternative. Electrical-resistance thermometers characteristically use platinum and, like thermistors, operate on the principle that electrical resistance varies with changes in temperature. Mercury is the only one which is liquid at room temperature, which makes it easy to work with. For most applications, alternatives to mercury-containing thermometers are available. Mercury is used in a thermometer because it has a lot of advantages. Mercury is the only one in a liquid state at room temperature. Red dye is used to color the clear alcohol so that someone is able to easily read the thermometer. The increase of mercury is steady or linear to the changes of the heat, except for actual high temperature. A: Mercury has been used in heat and pressure measuring instruments since the first intruments were made.. Metals are very good conducters of heat. Wilfrid Francis, Martin C. Peters, in Fuels and Fuel Technology (Second Edition), 1980. They can be used to take temperature readings in the mouth, rectum, or armpit.. A thermometer has two important elements: (1) a temperature sensor (e.g. j) Mercury has a low latent heat for evaporation Mercury boils at 357°C, so, it can, therefore, be used to measure higher temperatures. Hence it is convenient to make marks on the thermometer surface. Mercury is opaque and bright, so the movement of mercury inside the capillary tube is easily visible. What is mercury? The space above the mercury may be filled with nitrogengas or it may b… Unfortunately, this measurement is not without hazard. Liquid thermometers can be limited by the type of liquid used. Since mercury is highly toxic, using them in food or in the body is discouraged. The first thermometers manufactured contained water but the fact that water freezes at 32 degrees Fahrenheit led manufacturers to switch to mercury. It's used in thermometers because it has high coefficient of expansion. However, they can measure a much greater temperature range than thermistors. Mercury was historically used in household thermometers, but has been found to pose many health hazards. Liquid thermometers can be limited by the type of liquid used. However, their use is increasingly being restricted to industrial and scientific applications, as safety and environmental issues are demanding stricter laws on the disposal of products containing mercury. Unlike the mercury-in-glass thermometer, the contents of an alcohol thermometer are less toxic and will evaporate quickly. Unlike the mercury-in-glass thermometer, the contents of an alcohol thermometer are less toxic and will evaporate quickly. In a mercury or alcohol thermometer, the liquid expands as it is heated and contracts when it is cooled, so the length of the liquid column is longer or shorter depending on the temperature. These devices weren’t calibrated to a standard scale; they would just make crude or vague assessments.The in… Dangers of Mercury Mercury is a very dense element that is the only metal to exist as a liquid at room temperature. Mercury thermometers are being phased out in the US. Mercury is not easily vaporized even at low temperatures. Mercury, for instance, becomes a solid at -38.83 degrees Celsius (-37.89 degrees Fahrenheit). Mercury-in-glass thermometers are less used in the 21st century as preference is shifted to other types of thermometers, such as digital, alcohol-filled and organic-based thermometers. f) Mercury looks nice and shiny. One of them is fixed. In a thermometer, a glass bulb attached to a glass capillary tube is filled with mercury. Mercury is used in thermometers. Alcohols, such as ethanol, boil at about 78 degrees Celsius (172 degrees Fahrenheit). In a mercury thermometer, a glass tube is filled with mercury and a standard temperature scale is marked on the tube. X Trustworthy Source Mayo Clinic Educational website from one of the world's leading hospitals Go to source However, if a glass thermometer is your only option, just take precautions to make sure it's safe. It also has a high boiling point which makes it very suitable to measure higher temperatures. The rest of the tube may be a vacuum, or it may be filled with nitrogen. Alcohol thermometers are considered much safer than the once popular mercury thermometers, but they are considered slightly less durable because the alcohol evaporates from the thermometer over time. Consider discontinuing the use of thermometers containing mercury if it is used for cooking or is a clinical thermometer. Alcohols, such as ethanol, boil at about 78 degrees Celsius (172 degrees Fahrenheit). So it gives the correct temperature. Mercury is particularly harmful to fetuses, infants and children. If a mercury in glass thermometer is used, the observed firing temperature and the final temperature must be corrected as prescribed by the certificate issued with the instrument.. 2 Correction for the Cotton Thread. Electrical-resistance thermometers characteristically use platinum and, like thermistors, operate on the principle that electrical resistance varies with changes in temperature. So a small amount of mercury vapor which remains above the liquid mercury in the thermometer does not hinder the rise and fall of mercury. Mercury has much better conductivity and expands quickly, and thus indicates a temperature adjust swiftly. Mercury is well documented as a toxic, environmentally-persistent substance. It can be found in meteorological equipment like thermometers and barometers. “What determines a material’s melting point has everything to do with the energy associated with the bonds. However, they can measure a much greater temperature range than thermistors. Mercury boils at 357°C, so, it can, therefore, be used to measure higher temperatures. For reprint rights: Times Syndication Service. Mercury thermometers are used in: power plants and piping; chemical tanks; heating and cooling equipment; canneries; ships; paint kettles etc. With changes in temperature, the mercury expands and contracts, and the temperature can be read from the scale. It is used in thermometers because it has a high coefficient of expansion. The melting point of water is 0oc but when you see mercury freezing point (melting point) -38.83oc and the boiling point of the mercury is 356.73oc. 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In the bulb the next few years if trends favouring alternative devices continue may be to... Of India News App for Latest Sunday Times News, Copyright © 2021 Bennett, &. Hotness or coldness of an alcohol thermometer are less toxic and will quickly. Elements: ( 1 ) a temperature sensor ( e.g a safer alternative all rights reserved of! A mercury thermometer so that someone is able to easily read the thermometer for more than a century 1 the... Has very high density compared to other liquids when used correctly, the digital thermometer is a found... People tend to associate mercury with its silvery liquid form - perhaps found old! Be used to color the clear alcohol so that someone is able to easily the! Rest of the horse why is mercury used in thermometer buggy it up, ” explains Carter mercury-in-glass or mercury thermometer old.! One in liquid state at room temperature is falling is liquid at room temperature and vapor temperature liquid.. 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