It is known to all of the humans the use of the ear. The pair of the ear is used to detect any kind of sound wave from a certain amount of distance. At the same time, the frequency of sound should be in the certain range of frequency. The range of the frequency is around 20HZ-20KHZ and human won't be able to hear anything beyond that frequency range. Human ears are basically like the low-pass filter, therefore human ears are not capable of receiving high-frequency sound.
These are some basic fundamentals of the human ears. But, there are few functions of the human ears are yet to be discovered. It has been discovered that human ears have a very super ability and it is the distinguish the sound between a hot water flow and a cold water flow. A video from Tom Scott's youtube channel shows human ears can significantly distinguish between the hot water flow and cold water flow.
There are many people who are trying to figure out how human ears can figure out the differences between the hot water flow and cold water flow. many scientists are saying that human brain can subconsciously pick the difference between the hot and cold water flow. There is a significant amount of difference between the thickness of hot water and the cold water at the same time the viscosity of both hot and cold water is also different.
If you have seen both hot honey and cold honey that it is definite that you have probably seen the warmer honey has higher viscosity. While the honey with lower temperature has very low viscosity. The density of the honey is high, therefore the difference in the viscosity can be figured out in naked eyes. At the same time, the density of the water is 'one' therefore, it can be difficult to figure out the viscosity of hot and cold water in naked eyes.
But it is significant that the hot water has more energy as they have atoms in the higher energy state. At the same time, cold waters are denser and they don't have much less energy.