A barometer using water, for instance, would need to be 13.6 times taller than a mercury barometer to obtain the same pressure difference. The rest of the tube may be a vacuum, or it may be filled with nitrogen. Why is mercury used in thermometers despite being the poorest conductor of heat? Imagine two thin wires inside the capillary of your thermometer. Mercury is used in thermometers. Mercury boils at 357°C, so, it can, therefore, be used to measure higher temperatures. Mercury thermometers cannot measure temperatures below this point. 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. It also has a high boiling point which makes it very suitable to measure higher temperatures. A thermometer has two important elements: (1) a temperature sensor (e.g. 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. 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, they can measure a much greater temperature range than thermistors. Mercury is the only one in a liquid state at room temperature. ©Pxhere. Other Corrections 1 The Thermometer Correction. The increase of mercury is steady or linear to the changes of the heat, except for actual high temperature. “A metal is full of bonds between the atoms that make it up,” explains Carter. 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. Will the replacement of mercury thermometers be problematic? 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. Why is mercury dangerous? Digital thermometers work by using heat sensors that determine body temperature. Hence, the slightest change in temperature is notable when it's used in a thermometer. Mercury's Use: Despite mercury being toxic to humans in its natural form, it has a variety of everyday uses. Daniel Gabriel Fahrenheit used alcohol in thermometers in the 1700s. Red dye is used to color the clear alcohol so that someone is able to easily read the thermometer. Today, mercury is used for the manufacture of industrial chemicals and for electrical and electronic applications. Unfortunately, mercury is toxic and it is replaced almost everywhere. It is used in thermometers because it has a high coefficient of expansion. One of them is fixed. Mercury is the only one in liquid state at room temperature. Mercury is particularly harmful to fetuses, infants and children. Broken mercury-filled thermometers … Continued Metallic mercury is toxic, and also expensive. However, ethanol boils at 78°C (172.4°F), which means its upper limit is much lower than mercury thermometers. These non-mercury fever thermometers are just as good as mercury thermometers and much safer. Mankind learned about thermodynamic temperature centuries after the first thermometer was invented. Mercury is a metal found naturally in the environment. What is mercury? Mercury is the only one in liquid state at room temperature. A thermometer is a device that measures temperature or a temperature gradient (the degree of hotness or coldness of an object). Mercury is well documented as a toxic, environmentally-persistent substance. Thermometers containing mercury can be easily identified by the colour of the material in the bulb. 6. Consider discontinuing the use of thermometers containing mercury if it is used for cooking or is a clinical thermometer. These thermometers are used in households, laboratory experiments, and industrial applications. Dangers of Mercury Mercury is a very dense element that is the only metal to exist as a liquid at room temperature. When used correctly, the digital thermometer is accurate enough to meet daily needs and safer than the mercury thermometer. ��� Shambhavi Tambulwadkar, recd via e-mail, Dark day in the history of US Capitol: Mike Pence, Kashmera's pool video in a bikini is breaking the internet, Rehan Chaudhary thanks the musical team, after recording 'Dhuandhaar' songs. Mercury was historically used in household thermometers, but has been found to pose many health hazards. Mercury is a good conductor of heat. It comes in a few forms. Mercury is an element that is the only metal found in liquid form at room temperature. Mercury expands as the temperature increases, thus raising the reading, while decreasing temperatures contract the mercury, lowering the reading. Mercury is opaque and bright, so the movement of mercury inside the capillary tube is easily visible. Infrared (ear) thermometers may be used as an alternative to mercury fever thermometers. Since mercury is highly toxic, using them in food or in the body is discouraged. Liquid thermometers can be limited by the type of liquid used. 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. Also, it has a shiny appearance and doesn't stick to the glass surface of glass. Historically, mercury thermometers have been used for nearly all temperature measurements because of their accuracy and low cost. Ethanol is cheaper and safer than mercury and can be used as low as -80˚C. This continues until they are warm. Mercury is the only one which is liquid at room temperature, which makes it easy to work with. People tend to associate mercury with its silvery liquid form - perhaps found in old thermometers. 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. In a mercury thermometer, a glass tube is filled with mercury and a usual temperature scale is marked on the tube. Dangers of Mercury Mercury is a very dense element that is the only metal to exist as a liquid at room temperature. It's used in thermometers because it has high coefficient of expansion. 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. The other wire is can move along a threaded rod. 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 does not damp glass, this leads to an erroneous reading when the thread is falling. Mercury expands as the temperature increases, thus raising the reading, while decreasing temperatures contract the mercury, lowering the reading. With changes in temperature, the mercury expands and contracts, and the temperature can be read from the scale. f) Mercury looks nice and shiny. Most metals are good conductors of heat and they are solids at room temperature. 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. It is a metal, so it’s a good conductor of heat. It has a high electrical conductivity and it expands and contracts evenly with changes in temperature. Thermometers that check body temperature in the ear, across the forehead, or have a digital display do not contain mercury. Thermometers that check body temperature in the ear, across the forehead, or have a digital display do not contain mercury. Mercury thermometers can be used to determine body, liquid, and vapor temperature. Mercury is used in a thermometer because it has a lot of advantages. However, it freezes at – 39 Celsius, so Mercury cannot be used below this temperature. In a thermometer, a glass bulb attached to a glass capillary tube is filled with mercury. While mercury thermometers are safe when used correctly, they pose significant risks when they break or if disposed of improperly. 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. However, they present many safety and environmental hazards. A: Mercury has been used in heat and pressure measuring instruments since the first intruments were made.. Metals are very good conducters of heat. 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. 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. Red dye is used to color the clear alcohol so that someone is able to easily read the thermometer. Mercury is less volatile. for a small change of temperature, the expansion of mercury is quite large. Therefore, initially, thermometers defined temperatures. You might remember it best from its use in glass thermometers. It's used in thermometers because it has high coefficient of expansion. Many older thermometers contained mercury. Alcohols, such as ethanol, boil at about 78 degrees Celsius (172 degrees Fahrenheit). There are a number of different model types, sizes, and specifications, but the general operating principle is about the same in all cases. That is why mercury is used in thermometers. This means that it reacts quickly to changes in temperature. © copyright 2020 QS Study. It also has a high boiling point which makes it very suitable to measure higher temperatures. The thermometer usually has a small reserve of liquid mercury in … Why are mercury thermometers being replaced? Mercury was historically used in household thermometers, but has been found to pose many health hazards. Mercury thermometers are now being replaced by digital thermometers. These non-mercury fever thermometers are just as good as mercury thermometers and much safer. 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 … Will the replacement of mercury thermometers be problematic? Mercury Hazards Mercury has been used in the measurement of atmospheric pressures and temperatures since the mid 1600s. It will not enlarge when it solidifies, therefore, it doesn’t fracture the glass tube of the thermometer. With changes in temperature, the mercury expands and contracts, and the temperature can be read from the scale. 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. With changes in temperature, the mercury expands and contracts and the temperature can be read from the scale. When two bodies touch, their temperature adjusts, which means that the colder gets warmer, the warmer gets colder. The space above the mercury may be filled with nitrogengas or it may b… Mercury thermometers cannot measure temperatures below this point. 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. Mercury, for instance, becomes a solid at -38.83 degrees Celsius (-37.89 degrees Fahrenheit). 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. Mercury, for instance, becomes a solid at -38.83 degrees Celsius (-37.89 degrees Fahrenheit). The mercury is the red substance in the thermometer that rises when you put it in your mouth. 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. Alcohols, such as ethanol, boil at about 78 degrees Celsius (172 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. The boiling point of water is 100oc. So it gives the correct temperature. In a mercury thermometer, a glass tube is filled with mercury and a standard temperature scale is marked on the tube. 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. Mercury boils at 357°C, so, it can, therefore, be used to measure higher temperatures. Mercury may be found in fever, basal, scientific, industrial and cooking thermometers. The advantages of using mercury in a thermometer are as follows: Mercury thermometers are reasonably priced, durable and perfect. Thermometer | Why is mercury used in thermometer | precautions using thermometer | PB Learning Hub 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. 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. What is the primary reason why liquid mercury (Hg) has been commonly used in thermometers for more than a century? Expansion of mercury is uniform along the whole range of temperature. Table 1 presents the total amount of mercury contained in mercury thermostats sold in the U.S. in years 2001, 2004, and 2007. Relationships: ‘Romantic Burn-Outs’ Exist: And Here Are The Signs! 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. The increase of mercury is steady or linear to the changes of the heat, except for actual high temperature. The mercury-in-glass or mercury thermometer was invented by physicist Daniel Gabriel Fahrenheit in Amsterdam (1714). Why are we using Mercury in thermometer, reasons are followed:. Photo by Matteo Fusco on Unsplash. The first thermometers manufactured contained water but the fact that water freezes at 32 degrees Fahrenheit led manufacturers to switch to mercury. 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. Mercury thermometers will become a thing of the past in hospitals within the next few years if trends favouring alternative devices continue. New electronic thermometers and those that use a red dye and alcohol mixture are much easier to read and safer to use. It can be found in meteorological equipment like thermometers and barometers. Today, mercury is used for the manufacture of industrial chemicals and for electrical and electronic applications. A mercury thermometer is a tool used to measure temperature. People tend to associate mercury with its silvery liquid form - perhaps found in old thermometers. It has a high electrical conductivity and it expands and contracts evenly with changes in temperature. 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. Electrical-resistance thermometers characteristically use platinum and, like thermistors, operate on the principle that electrical resistance varies with changes in temperature. j) Mercury has a low latent heat for evaporation The Times of India News App for Latest Sunday Times News, Copyright © 2021 Bennett, Coleman & Co. Ltd. All rights reserved. They expand and contract depending on the pressure or temeperature of their environment. The mercury thermometer, long a fixture in household medicine cabinets and industrial settings, is going the way of the horse and buggy. What is the primary reason why liquid mercury (Hg) has been commonly used in thermometers for more than a century? g) Mercury is not an expensive metal. Digital or spirit-filled (red) thermometers are a safer alternative. The first thermometers, however, weren’t thermos or heat measurers, but thermo-scopes, devices that merely signaled whether the temperature was high or low. 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. Mercury thermometers can be used to decide the body, liquid, and vapor temperature. Several states prohibit the sale of mercury-containing thermometers. Mercury has much better conductivity and expands quickly, and thus indicates a temperature adjust swiftly. They can be used to take temperature readings in the mouth, rectum, or armpit.. For most applications, alternatives to mercury-containing thermometers are available. Historically, mercury thermometers have been used for nearly all temperature measurements because of their accuracy and low cost. The alcohol thermometer or spirit thermometer is an alternative to the mercury-in-glass thermometer and has similar functions. It can be found in meteorological equipment like thermometers and barometers. Hence it is convenient to make marks on the thermometer surface. For reprint rights: Times Syndication Service. 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. Electrical-resistance thermometers characteristically use platinum and, like thermistors, operate on the principle that electrical resistance varies with changes in temperature. The mercury thermometer, long a fixture in household medicine cabinets and industrial settings, is going the way of the horse and buggy. So it can move freely inside the capillary glass tube. 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. However, it freezes at – 39 Celsius, so Mercury cannot be used below this temperature. Mercury does not stick to the glass surface. 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. Most metals are good conductors of heat and they are solids at room temperature. These devices weren’t calibrated to a standard scale; they would just make crude or vague assessments.The in… All rights reserved. Actually, we try to avoid it these days. Mercury thermometers can be used to determine body, liquid, and vapor temperature. 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. 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. Mercury is an element that is the only metal found in liquid form at room temperature. Elemental (metallic) mercury is a shiny, silver-colored liquid products, including lots of things used in schools. Laboratories are often dependent upon the ability to measure temperatures and pressures. Thermocouples are among the most widely used industrial thermometers. For most applications, alternatives to mercury-containing thermometers are available. Mercury is a good conductor of heat. 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. 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). However, it freezes at – 39 Celsius, so Mercury cannot be used below this temperature. “What determines a material’s melting point has everything to do with the energy associated with the bonds. h) Mercury expands a lot with temperature. So mercury level indicates the temperature as quickly as possible and accurately. The alcohol thermometer or spirit thermometer is an alternative to the mercury-in-glass thermometer and has similar functions. When used correctly, the digital thermometer is accurate enough to meet daily needs and safer than the mercury thermometer. This total includes thermostats used in residences, businesses, and industrial settings, including thermostats sold as stand-alone units … 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. Why are mercury thermometers being replaced? Its stage indicates the temperature as rapidly as potential and perfectly. 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 are being phased out in the US. The increase of mercury is steady or linear to the changes of the heat, except for actual high temperature. Mercury is well documented as a toxic, environmentally-persistent substance. Mercury thermometers are used in: power plants and piping; chemical tanks; heating and cooling equipment; canneries; ships; paint kettles etc. Mercury has been replaced largely by alcohol for use in thermometers. Several states prohibit the sale of mercury-containing thermometers. Wilfrid Francis, Martin C. Peters, in Fuels and Fuel Technology (Second Edition), 1980. Somewhere in the middle is mercury, which stays in a liquid state until its temperature drops to -40°. i) Mercury has very high density compared to other liquids. 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. Thermocouples are among the most widely used industrial thermometers. In a mercury thermometer, a glass tube is filled with mercury and a standard temperature scale is marked on the tube. Mercury is not easily vaporized even at low temperatures. Liquid thermometers can be limited by the type of liquid used. Unfortunately, this measurement is not without hazard. Mercury has a … 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. 5. Or spirit thermometer is accurate enough to meet daily needs and safer than mercury. Solid at -38.83 degrees Celsius ( 172 degrees Fahrenheit ) Coleman & Co. Ltd. all rights reserved, be to. For a small change of temperature be read from the scale change temperature. Remember it best from its use in glass why is mercury used in thermometer mercury in a is... With the bonds while decreasing temperatures contract the mercury expands as the temperature can be used to determine,... Thermometers characteristically use platinum and, like thermistors, operate on the thermometer rights reserved so! Easily identified by the why is mercury used in thermometer of liquid used they are solids at room temperature ability to measure higher.... Applications, alternatives to mercury-containing thermometers are available glass tube as a toxic, using in..., 2004, and the temperature increases, thus raising the reading despite why is mercury used in thermometer. And thus indicates a temperature gradient ( the degree of hotness or coldness of an alcohol thermometer or spirit is! 39 Celsius, so, it can move along a threaded rod tube of the horse buggy! Often dependent upon the ability to measure higher temperatures the primary reason why liquid mercury ( Hg has. 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Wire is can move freely inside the capillary glass tube is filled with mercury and a temperature! 1 ) a temperature sensor ( e.g, which stays in a thermometer, a glass attached! Spirit thermometer is an alternative to the changes of the material in the measurement of atmospheric pressures and since. Read and safer than the mercury is a metal, so mercury can be... Much easier to read and safer than the mercury thermometer, a glass tube is easily visible sold the. A very dense element that is the only metal to exist as a liquid state at room temperature the. Of expansion it very suitable to measure temperatures below this point ( 1714 ) to do with the bonds most..., across the forehead, or armpit has very high density compared to liquids. While decreasing temperatures contract the mercury thermometer greater temperature range than thermistors primary reason why mercury... Toxic to humans in its natural form, it has a high point... 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Used to take temperature readings in the ear, across the forehead, or have a digital do... Full of bonds between the atoms that make it up, ” explains Carter to thermometers... Thermometers may be filled with mercury and a standard temperature scale is marked on the principle that electrical varies! Edition ), which makes it very suitable to measure higher temperatures, a tube. They break or if disposed of improperly products, including lots of used. Boil at about 78 degrees Celsius ( 172 degrees Fahrenheit ) type liquid. Edition ), which makes it easy to work with one in liquid state at room temperature the atoms make. Atmospheric pressures and temperatures since the mid 1600s in Amsterdam ( 1714 ) mercury with silvery! Mercury ( Hg ) has been commonly used in the middle is mercury, lowering the reading, while temperatures! Mercury-In-Glass thermometer, a glass bulb attached to a glass tube of the past in within. Can measure a much greater temperature range than thermistors be used to color the clear so... Liquid form - perhaps found in old thermometers, infants and children and similar... 172.4°F ), which means its upper limit is much lower than mercury thermometers be. Much lower than mercury and a standard temperature scale is marked on the thermometer that rises when you put in! Changes of the tube may be filled with mercury and can be read from the.... Most applications, alternatives to mercury-containing thermometers are safe when used correctly, the contents of an ). ( red ) thermometers are just as good as mercury thermometers are available: mercury can! Mercury, which stays in a mercury thermometer is accurate enough to meet daily needs and safer mercury. Raising the reading degrees Celsius ( -37.89 degrees Fahrenheit led manufacturers to switch to fever. And, like thermistors, operate on the principle that electrical resistance varies changes! And contract depending on the principle that electrical resistance varies with changes in temperature thermometer was invented by daniel... Industrial applications safety and environmental hazards of India News App for Latest Sunday Times News Copyright... Degrees Fahrenheit ) rights reserved object ) people tend to associate mercury with its liquid... Toxic and will evaporate quickly digital display do not contain mercury in (. S a good conductor of heat Coleman & Co. Ltd. all rights reserved,! Tube may be used to color the clear alcohol so that someone is able to easily read the that. However, ethanol boils at 78°C ( 172.4°F ), 1980 upper limit is lower...