# Why an open tube at both ends suffers resonance? [duplicate]

Why an open tube at both ends suffers resonance when subjected to a sound that propagates through the air with length of where $$L / 2$$?

I already know the methodology to calculate the harmonics in an open tube. So, I'm not expecting an answer that is based on the calculations. I want to know why this phenomenon occurs from the molecular point of view of the air, taking into account that air could be considered as an ideal gas whose molecules have no interaction with each other.