Construction and working of mercury thermometer

A device used to measure the pressure at any point in a fluid, manometers are also used to measure the pressure of gas and air. Metallic mercury is a shiny, silverwhite, odorless liquid. The funnel a having been filled with pure dry mercury, the bulb d is slightly. Mercury is poisonous, so a mercury barometer requires special handling. Outlines mercury in its three general forms and provides additional information on its properties and the health effects. When the temperature of the bulb of the thermometer increases, the mercury tends to expand and fill the capillary tube to certain level depending on the temperature.

Usually, mercury or some kind of alcohol is used for the liquid. By repeating this operation the size of the bulb may be increased as required. Measure temperature in soil, cuvets, test tubes, food products, incubators, petroleum hydrocarbons, and virtually all lab tests. This is a device that combines the major utilities and modes of the other major players but priced much more aggressively.

It is used to record the extremes of temperature at a location, for instance in meteorology and horticulture. Taking some pure and clean mercury in the funnel the capillary tube is filled with mercury by successive heating the cooling. Thermometer is a device used for measuring the temperature. Well type manometer construction and working with derivation in hindi. A thermometer gun is used to check the temperature of a customer as he enters a supermarket in. Construction of a mercury thermometer construction of a mercury thermometer. The resistance thermometer is placed inside the protective tube for providing the protection against damage.

The mercuryinglass or mercury thermometer was invented by physicist daniel gabriel fahrenheit in amsterdam 1714. The tube is then withdrawn from the flame and a small bulb is blown at the end. The basic principle of a mercury thermometer all thermometers work on the principle that warm fluids occupy more space than cold fluids. The resistive element is formed by placing the platinum wire on the ceramic bobbin. The bimetallic thermometer uses the bimetallic strip which converts the temperature into the mechanical displacement. The mercuryinglass or mercury thermometer was invented by physicist daniel gabriel. Resistance temperature detector or rtd construction and. One problem with mercury and dial thermometers is that they take a while to react to temperature changes. Mercury thermometers are based on the principle that liquids expand when heated and contract when cooled. The gas is enclosed in the bulb b and the pressure recorded by the difference in levels h of the mercury columns. The thermal expansion of mercury is proportional to the temperature of the mercury, so more is the. The scale is calibrated to read temperature directly. If you have a mercury thermometer, dont throw it in the trash.

So, when the temperature increases, the mercury expands and rises up the tube and when the temperature decreases it contracts and does the opposite. Mercury thermometers are no longer recommended because they can break and allow mercury which is toxic to escape. In selecting a tube for the construction of a thermometer, it is most important to determine whether the bore is uniform throughout the length to be used. As the temperature around the thermometers bulb heats up, the liquid rises in the glass tube. Here i have added introduction, history, advantages,disadvantages, use and etc slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. In a thermometer, a glass bulb attached to a glass capillary tube is filled with. This work focuses on the a digital thermometer, it consists of a thermister to sense the temperature and an electronic display of the temperature. Easy and accurate reading of the body temperature can be made with these mercury. Usually, laboratory thermometer is made in celsius scale which has scaled from 10 0 c to 110 0 c.

With changes in temperature, the mercury expands and contracts, and the temperature can be read from the scale. What is the principle of how a mercury thermometer works. What is the working and construction of thermometer answers. This point may be settled by carefully sucking a short thread of mercury into the tube, and measuring its length when occupying various positions. Different types of thermometers are used for different purposes. Laboratory thermometer can be used to measure both hot and cold substances. An instrument used for measuring the temperature change occurs in the human body or any other object is termed as the thermometer. This handy dual scale mercury thermometer is a necessity for each home, office, clinic and hospital. Dp33 mercury thermometer clinical, prismatic, dual scale, economy model. Since we know how much space a fluid such as mercury will fill at any given temperature, we are therefore able to determine the temperature of that fluid by measuring how much space it takes up. The mercury is forced up through the constriction by the force of expansion as the temperature increases.

This means that one can be carried in a car or on a ship. This resistance element is placed inside the tube which is made up of stainless steel or copper steel. High mercury exposure results in permanent nervous system and kidney damage. The working of the bimetallic strip depends on the thermal expansion property of the metal. Mercury thermometer expands and contracts according to the rise or fall in temperature.

If mercury freezes, nitrogen can be caught behind the metal causing the thermometer to stop working. Mercury thermometer, buy mercury thermometers, clinical. Some of the health effects exposure to mercury may cause include. Thermo electric thermometer is a special device which measures high as well as low temperature. Mercury thermometer thermometer is a device used for measuring the temperature. It has good linear characteristics over a wide range of temperature.

Safe for all lab tests stainlesssteel and plastic construction no glass or mercury makes it the safest lab thermometer ever designed. The glass tube is mounted on a backboard that is marked in units called degrees. Give the construction and working of a thermometer. Exposure is most likely to occur during mining, production, and transportation of mercury, as well as mining and refining of gold and silver ores. It consists of a bulb containing mercury attached to a glass tube of narrow diameter. Calibration of thermometer, zeroth law and construction of. Latest digital thermometer with single microcontroller and. Sixs thermometer is a registering thermometer which can record the maximum and minimum temperatures reached over a period of time, for example 24 hours.

A mercury thermometer has a bulb with a capillary tube attached to it surrounded by glass tube casing on which degrees are mentioned. Provides information on methods for sampling the difference forms of mercury. The range in which it can measure the temp is nearly 200oc to 1600oc. To construction a mercury thermometer, a clean fine glass capillary tube having a bulb at one end is taken as shown in the figure.

The mercury level at r is always adjusted so that it coincides with the mark. Another common variety of barometer is a mercury barometer. A resistance thermometer or resistance temperature detector is a device which used to determine the temperature by measuring the resistance of pure electrical wire. Mercury is commonly found in thermometers, manometers. Mercury hazards are addressed in specific osha standards for general industry, shipyard employment, and construction. One special kind of mercuryinglass thermometer, called a maximum thermometer, works by having a constriction in the neck close to the bulb. Mercury has been frequently used in thermometers because it remains in liquid form throughout a wide range of temperatures. As the temperature rises, the liquid expands, moving up the tube. The uses of mercury in glass thermometers sciencing. A thermometer is a device that measures temperature or a temperature gradient. This is the reason behind mercury and alcohol being used in thermometer. Mercury can be toxic if consumed, and it can also cause skin and eye damage if touched or respiratory distress if inhaled. Give the construction and working of a thermometer 73652 a thermometer has a glass tube sealed at both ends and is partly filled with a liquid like mercury or alcohol. The digital thermometers are used to measure human body temperature around 37.

The working principle, types, and applications of a. Safety and health topics mercury occupational safety. For covid19 coronavirus, how well do thermometer guns. Mercury is naturally occurring and exists in several forms. The bulb is filled with pure and dry mercury with the help of funnel by alternate heating and cooling. Due to the narrow bore of the tube a small change in the volume of the mercury becomes significiantly visible.

Bimetallic thermometer construction and working in. In selecting a tube for the construction of a thermometer, it is most. An aneroid barometer has the added advantages of being smaller and lighter and easier to move safely. This wasnt a new idea, since isaac newton was already working on. Place the bulb of the thermometer filled with mercury in a vessel ov small pieces of ice the mercury will arise in the tube and will come to rest at a certain point. Taking some pure and clean mercury in the funnel the capillary tube is filled with mercury by successive heating the cooling the bulb. These thermometers are mostly probe type or ear type. The thermometer doesnt needs to be shaken for the proper mercury level, hence the risk of the tube getting broken is eliminated. To construct a mercury thermometer physics homework help. A maximum thermometer is a unique kind of mercury thermometer which functions by having a constriction in the neck close to the bulb. The caroune ir thermometer is a do it all thermometer with all the functionalities, bells and whistles that are bound to be a major player in the household commercial grade thermometer market. Liquid in glass thermometer principle instrumentation tools. The thermal expansion is the tendency of metal in which the volume of metal changes with the variation in temperature. Selection of temperature measurement instrument 66.

Notes on types of thermometer according to construction. Thermometer construction edser humboldt state university. Digital thermometers are used orally, rectally or under the arm. A simple form of constantvolume gas thermometer is shown in figure. It was invented by a british scientist james six, born in canterbury, in 1780. The volume of mercury changes slightly with temperature. It has an inbuilt mercuryinglass construction and dual reading in farenheightcelsius. Bimetallic thermometer construction and working in hindi.

If we want to measure temperature with high accuracy, rtd is the only one solution in industries. A thermometer consists of a glass bulb filled with mercury. Contact your local trash collection program to see if theres a hazardous waste collection site in your area. Calibration mercury thermometer at thomas scientific. Contact your local trash collection program to see if theres a. So, when its bulb having mercury filled in it,come in touch with something hotter or colder or even having mode. The aneroid barometer is superior in some ways to this. Due to the narrow bore of the tube a small change in the volume of the mercury. A thermometer has a glass tube sealed at both ends and is partly filled with a liquid like mercury or alcohol.