Most metals are good conductors of heat and they are solids at room temperature. 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. It is used in thermometers because it has a high coefficient of expansion. Mercury is the only one in liquid state at room temperature. Mercury has been replaced largely by alcohol for use in thermometers. In a thermometer, a glass bulb attached to a glass capillary tube is filled with mercury. Hence it is convenient to make marks on the thermometer surface. Table 1 presents the total amount of mercury contained in mercury thermostats sold in the U.S. in years 2001, 2004, and 2007. 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. Unlike the mercury-in-glass thermometer, the contents of an alcohol thermometer are less toxic and will evaporate quickly. Today, mercury is used for the manufacture of industrial chemicals and for electrical and electronic applications. This total includes thermostats used in residences, businesses, and industrial settings, including thermostats sold as stand-alone units … Broken mercury-filled thermometers … Continued 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 is well documented as a toxic, environmentally-persistent substance. Mercury boils at 357°C, so, it can, therefore, be used to measure higher temperatures. i) Mercury has very high density compared to other liquids. People tend to associate mercury with its silvery liquid form - perhaps found in old thermometers. Thermometers containing mercury can be easily identified by the colour of the material in the bulb. Mercury has a … Alcohols, such as ethanol, boil at about 78 degrees Celsius (172 degrees Fahrenheit). A mercury thermometer is a tool used to measure temperature. With changes in temperature, the mercury expands and contracts, and the temperature can be read from the scale. Historically, mercury thermometers have been used for nearly all temperature measurements because of their accuracy and low cost. Mercury thermometers will become a thing of the past in hospitals within the next few years if trends favouring alternative devices continue. 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. Thermocouples are among the most widely used industrial thermometers. Mercury is particularly harmful to fetuses, infants and children. Will the replacement of mercury thermometers be problematic? Metallic mercury is toxic, and also expensive. Why is mercury dangerous? Mercury, for instance, becomes a solid at -38.83 degrees Celsius (-37.89 degrees Fahrenheit). The increase of mercury is steady or linear to the changes of the heat, except for actual high temperature. ©Pxhere. The mercury-in-glass or mercury thermometer was invented by physicist Daniel Gabriel Fahrenheit in Amsterdam (1714). When used correctly, the digital thermometer is accurate enough to meet daily needs and safer than the mercury thermometer. 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. Dangers of Mercury Mercury is a very dense element that is the only metal to exist as a liquid at room temperature. 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. A barometer using water, for instance, would need to be 13.6 times taller than a mercury barometer to obtain the same pressure difference. What is mercury? Mercury thermometers can be used to decide the body, liquid, and vapor temperature. It is a metal, so it’s a good conductor of heat. Several states prohibit the sale of mercury-containing thermometers. Thermometer | Why is mercury used in thermometer | precautions using thermometer | PB Learning Hub 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. 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 … While mercury thermometers are safe when used correctly, they pose significant risks when they break or if disposed of improperly. Mercury thermometers are used in: power plants and piping; chemical tanks; heating and cooling equipment; canneries; ships; paint kettles etc. The alcohol thermometer or spirit thermometer is an alternative to the mercury-in-glass thermometer and has similar functions. Liquid thermometers can be limited by the type of liquid used. So it gives the correct 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. It has a high electrical conductivity and it expands and contracts evenly with changes in temperature. So it can move freely inside the capillary glass tube. However, it freezes at – 39 Celsius, so Mercury cannot be used below this temperature. 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 alcohol thermometer or spirit thermometer is an alternative to the mercury-in-glass thermometer and has similar functions. The space above the mercury may be filled with nitrogengas or it may b… However, it freezes at – 39 Celsius, so Mercury cannot be used below this temperature. It's used in thermometers because it has high coefficient of expansion. It can be found in meteorological equipment like thermometers and barometers. Why are we using Mercury in thermometer, reasons are followed:. New electronic thermometers and those that use a red dye and alcohol mixture are much easier to read and safer to use. Mercury expands as the temperature increases, thus raising the reading, while decreasing temperatures contract the mercury, lowering the reading. Most metals are good conductors of heat and they are solids at room temperature. Mercury is opaque and bright, so the movement of mercury inside the capillary tube is easily visible. Alcohols, such as ethanol, boil at about 78 degrees Celsius (172 degrees Fahrenheit). Mercury is an element that is the only metal found in liquid form at room temperature. 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. When two bodies touch, their temperature adjusts, which means that the colder gets warmer, the warmer gets colder. g) Mercury is not an expensive metal. Mercury is the only one which is liquid at room temperature, which makes it easy to work with. Daniel Gabriel Fahrenheit used alcohol in thermometers in the 1700s. Mercury is well documented as a toxic, environmentally-persistent substance. It will not enlarge when it solidifies, therefore, it doesn’t fracture the glass tube of the thermometer. Mercury has much better conductivity and expands quickly, and thus indicates a temperature adjust swiftly. 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. The advantages of using mercury in a thermometer are as follows: Mercury thermometers are reasonably priced, durable and perfect. 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 rest of the tube may be a vacuum, or it may be filled with nitrogen. A: Mercury has been used in heat and pressure measuring instruments since the first intruments were made.. Metals are very good conducters of heat. Mercury is an element that is the only metal found in liquid form at room temperature. ��� 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. Laboratories are often dependent upon the ability to measure temperatures and pressures. j) Mercury has a low latent heat for evaporation Mercury does not damp glass, this leads to an erroneous reading when the thread is falling. That is why mercury is used in thermometers. Mercury is a good conductor of heat. Thermometers that check body temperature in the ear, across the forehead, or have a digital display do not contain mercury. They can be used to take temperature readings in the mouth, rectum, or armpit.. 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