Why we use mercury in the thermometer why we should not use any other liquid for the thermometer
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Liquid in glass thermometers are the cheapest kind of thermometer, and are also easy to use. Mercury is easily the best liquid to use, for 5 important reasons.
1. It is very reflective, so it's easy to see and to read accurately.
2. It doesn't wet the glass, so you don't get inaccurate readings if the temperature is falling.
3. It is a metal, so it's a good conductor of heat. This means that it reacts quickly to changes of temperature.
4. It expands evenly with temperature, so a linear scale can be used with quite a high degree of accuracy.
5. There's a large range of temperature for which it is a liquid. However, it freezes at - 39 Celsius, so Mercury cannot be used below this temperature. It boils at 365 Celsius, which is high enough for most purposes.
Colored water is no good because it's a poor conductor, it wets the glass, it expands unevenly with temperature, and there is only a limited range of temperatures for which it is a liquid, 0 - 100 Celsius.
Cheaper, and for temperatures below -39 C, colored ethanol is used. This freezes at - 144 C, but it boils at 78 C, making it of no use at high temperatures. It expands quite evenly with temperature, but otherwise it has the same defects as water. To get an accurate reading, it should be vertical and you have to give it plenty of time before you take a reading.
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1. It is very reflective, so it's easy to see and to read accurately.
2. It doesn't wet the glass, so you don't get inaccurate readings if the temperature is falling.
3. It is a metal, so it's a good conductor of heat. This means that it reacts quickly to changes of temperature.
4. It expands evenly with temperature, so a linear scale can be used with quite a high degree of accuracy.
5. There's a large range of temperature for which it is a liquid. However, it freezes at - 39 Celsius, so Mercury cannot be used below this temperature. It boils at 365 Celsius, which is high enough for most purposes.
Colored water is no good because it's a poor conductor, it wets the glass, it expands unevenly with temperature, and there is only a limited range of temperatures for which it is a liquid, 0 - 100 Celsius.
Cheaper, and for temperatures below -39 C, colored ethanol is used. This freezes at - 144 C, but it boils at 78 C, making it of no use at high temperatures. It expands quite evenly with temperature, but otherwise it has the same defects as water. To get an accurate reading, it should be vertical and you have to give it plenty of time before you take a reading.
THANKU AND PLEASE MARK AS BRAINLIST ANSWER
moniko:
From where do I get the brain list to add this answer
you have option on my answer
thank u monika
thank you
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because mercury has comparatively low melting point than those of other metals.It exert exactly 1 ATM pressure of 760mm of it.Thats why 1atm=760mm of Hg where Hg is atomic symbol of mercury.its an special metal
thank you for answering my question
wlcm
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