Air molecules are indeed in constant random motion, and they follow the basic principles of gas behavior and fluid dynamics. The movement of air into a vacuum cleaner's hose is not guided by any intentional knowledge or consciousness of the air itself. Instead, it is driven by simple physical laws that govern the behavior of gases:
Pressure Difference: The key principle at play here is the pressure difference between the inside and outside of the vacuum cleaner's hose. When the vacuum cleaner is turned on, it creates a partial vacuum inside the hose by rapidly spinning a fan or impeller. This leads to a lower pressure inside the hose compared to the surrounding atmosphere.
High to Low Pressure: Air naturally flows from areas of higher pressure to areas of lower pressure. In this case, the air outside the vacuum cleaner's hose has a higher pressure than the air inside the hose. As a result, air from the surrounding environment rushes into the hose to equalize the pressure difference.
Nozzle Placement: When you place the vacuum cleaner's nozzle on a surface, it creates a seal, and the air has no alternative path to go but into the hose. The nozzle directs the airflow, making sure that the air, along with dust and debris from the surface, enters the hose.
Continued Suction: As long as the vacuum cleaner is running and the motor is creating a pressure difference, the air will continue to flow into the hose, carrying dirt and debris with it.
So, it's not that the air "knows" to go down the vacuum cleaner's hose; rather, it simply follows the laws of physics by moving from an area of higher pressure (outside the hose) to an area of lower pressure (inside the hose) when a pressure difference is established. The nozzle placement ensures that the air is directed into the hose, allowing the vacuum cleaner to effectively clean the desired surfaces.