Following the recent post of Quanta Magazine, I gave a talk in Persian with the same title at Amirkabir University of Technology (AUT). I began by introducing "collective behavior" and its different types and went through the concept of active matter and linked the swelling bacteria to physics of phase transition.
Original Post:
https://www.quantamagazine.org/swirling-bacteria-linked-to-the-physics-of-phase-transitions-20170504/
My slides:
http://www.sitpor.org/wp-content/uploads/2016/08/Swirling-Bacteria-1.pdf