How was thermometer invented?


DOCTORS always use a thermometer to measure and check your body temperature when you have a fever. Have you ever wondered, how thermometer was invented?
In 1596, Galileo Galilei invented the thermoscope, an instrument that can only show if the temperature is higher, lower or same, as it did not have a scale.

Later in 1612, an Italian inventor named Santorio Santorio applied a scale to an air thermoscope. But its accuracy was poor as the effect of varying air pressure on the thermoscope was not understood at that time.