The invention of liquid thermometers was inspired by the human body. The picture below shows an example liquid thermometer.
There is a reservoir of liquid at the bottom of the thermometer.
That liquid will raise and lower to different heights within the tube above the reservoir,
depending on the temperature.
The most obvious inspiration from the human body is of course the male sex organ.
A thermometer looks like a male sex organ.
The mercury reservoir bulb at the bottom of the thermometer looks like the scrotum.
The glass column itself is the penis.
The thermometer would have been based on the concept that when the penis is sexually stimulated or “hot”, it rises upwards.
The second inspiration from the human body is less obvious but also involves the sex organs. When the human body is stimulated sexually, and also in other ways, there are areas of the back that can “rise up” in the same way that the penis rises up when it is stimulated. When these areas are not stimulated, they shrink or lower the same way a penis shrinks or lowers.
The scrotum again plays the part of the mercury bulb in this example with the back playing the part of the straight section of a thermometer.
