Why don't the temperature of the thermometer material with water?

1. Melting point and boiling point in the standard state of the melting point of water ( Freezing point) Is 0 ℃, the boiling point of water is 100 ℃, melting point and mercury ( Freezing point) Is - 38. 5 ℃, boiling point is 357 ℃; The melting point of alcohol ( Freezing point) Is - 114 ℃, boiling point is 78 ℃; Good paraffin melting point ( Freezing point) Is - 30 ℃, boiling point is 325 ℃. If use thermometer to measure the temperature of water, winter under 0 ℃, hardened into ice water, you can't measure; When the temperature reached 100 ℃ water will boil, although due to the tube increases with the increase of water vapor pressure, the boiling point of water but the water volume expansion and steam pressure of the scale of increase is very complex, is not proportional relationship, so can't use the measuring temperature above 100 ℃. Mercury is different, can be measured with it - 38. The temperature between 5 ℃ ~ 357 ℃; Alcohol while the boiling point is not high, but its melting point ( Freezing point) Is - Above 114 ℃, 114 ℃ below zero namely wouldn't freeze; Use kerosene can measure - Temperature of 30 ℃ ~ 325 ℃. 2. The thermal expand coefficient of thermal expansion coefficient of water to 2. 1× 10 ^ - 3 / ℃, mercury, alcohol, the thermal expansion coefficient of kerosene 1 respectively. 8× 10 ^ - 4/℃、1. 1× 10 ^ - 3/℃、1. 0× 10 ^ - 3/℃。 The same volume of liquid were elevated 1 ℃, alcohol and the expansion of the kerosene water volume is about five times, so in terms of using the volume change of the scale, the scale of water from small, alcohol and the large scale distance of kerosene, the temperature of the same distance, not only bring convenience for measurement and reading, and can measure temperature changes smaller values. 3. The heat capacity of the heat capacity of water is 4. 2× 10^3J/( kg• ℃) , the heat capacity of the mercury, kerosene, alcohol respectively 0. 14× 10^3J/( kg• ℃) , 2. 4× 10^3J/( kg• ℃) , 2. 1× 10^3J/( kg• ℃) : what is the specific heat of the water mercury 30 times, if the quality of the same water and mercury, the same amount of heat is absorbed, mercury rise in temperature is 30 times the water; Visible with water thermometer effects on the temperature of the object to be tested is big, long reach thermal equilibrium; Mercury thermometer and small effects on the temperature of the object to be tested, reach thermal equilibrium time is short. Especially the measurement of small objects, if the thermometer have an effect on it, the temperature of the measured value is not accurate. 4. Water's abnormal inflation in more than 4 ℃, the same as the general material is heat bilges cold shrink, but between 0 ℃ and 4 ℃ heat bilges cold shrink, and this period of heat bilges cold shrink coefficient with different heat bilges cold shrink. This is a kind of special properties of water, if the thermometer is filled with water, not only can't scale scale between 0 ℃ to 4 ℃, at about 4 ℃ with the thermometer temperature, unable to determine the readings. From the above analysis we can see that the thermometer can't hold water, there are a variety of reasons, mainly based on the physical properties of liquid and the selected liquid thermometer measurement range and moreover different purpose and each are not identical, such as the alcohol thermometer cannot be used for high temperature measurement, mercury thermometer thermometer is used, and so on.