Trying to understand alveolar surface tension

[samy4408]

TL;DR Summary

I need a satisfactory explanation about alveolar surface tension

Hello, I learned recently about alveolar surface tension, and the explanation provided in the course was not satisfactory, it said that it is due to the force that pushes water molecules of the outer layer to the inner layers, I don't understand why this force that pushes water toward the cell walls is the origin of another force that pusher water in the opposite direction.
can someone give me a satisfactory explanation, tanks.

 

[Borek]

I am not sure I follow, but typically when people have problems like the one you are describing they forget they should be comparing two situations, not analyze them separately.

Try to not think in terms of "what this force does" but in terms of "what will happen when I remove the other force". You probably should be comparing two situations: first, with the forces that act in all directions and cancel each other (so the net effect is zero), second, where half of the forces were removed and the net effect is opposite to what the left forces suggest.