If I place a mercury thermometer in hot water, heat energy will transfer from the water to the mercury inside the thermometer. Will this continue until thermal equilibrium is reached and thus the mercury will show the temperature of the water?
However, if this is so, will the thermometer show the right temperature as some of the heat energy is transferred to the thermometer and this in turn will cause original temperature of water to fall?
Please correct me if I am wrong.
Best Answer
You are right. The thermal equilibrium will eventually be reached. In this process, heat is transferred from the water to the thermometer. This increases the temperature of the thermometer and decreases the temperature of the water until they are equal.
However, generally, the amount of water is large so that the heat it loses is too small to significantly change its temperature.