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