I was interested in making an experiment and started to see what thermometer is best to use, when I became confused to where exactly is the measurement comes from.
For example, If I dip a mercury thermometer into a cup of water & oil, where is the measurement being received from?
The tip, only with the mercury sits? Or the temperature of the area dipped in both
Another example would be the prong style thermometers with a metal rod or whatever.
Is the reading an average of the temps throughout the rod? Or just the tip?