What is the red liquid in the glass rod thermometer?

Common glass rod are red liquid in the thermometer, we all know this is medium temperature, then you know what is the red liquid? Today we speak of what is inside the glass rod thermometer red liquid and its role. In general, the inside of the glass rod thermometer red liquid of alcohol or kerosene, in order to facilitate observation, added a red fuel. Using alcohol made of heat bilges cold everybody understands the nature of the alcohol thermometer. Under a standard atmospheric pressure, alcohol thermometer can measure the highest temperature is 78 ℃ commonly. Because alcohol under a standard atmospheric pressure, the boiling point is 78 ℃. But the pressure within the thermometer is generally higher than 1 standard atmosphere, so there are some alcohol thermometer range greater than 78 degrees. In the north cold season often use alcohol thermometer to measure temperature, condensation point is - this is because the mercury 39 ℃, in cold areas may be because the temperature is too low and make the mercury solidification, unable to normal temperature measurement. And the freezing point of alcohol is - 114 ℃, don't have to worry about this problem. Made by using the properties of kerosene heat bilges cold shrink kerosene thermometer and its boiling point is generally higher than 150 ℃, below the freezing point 30℃。 So a measure of the kerosene thermometer range is about - 30℃～150℃。 Because of the boiling point of alcohol is 78 ℃, freezing point is - 117 ℃, the alcohol thermometer can lower than kerosene thermometer measured temperature, but it cannot determine the above 78 ℃ temperature.