text: This is a very complex subject.  It is true that there are \nhdydrogen bonding, but i will try to make it easier for you\nto picture it.\n\nThink of  a jar of beans (water), then you pour in rice (ethanol). At 1st the rice will go in between the beans.\nSo the total volume goes down.\nAfter a while the rice will fill by itself over the beans, so the total volume goes up.  This is not excatly correct, but it gives you a model for picturing it in your mind.  In the real case, the beans and rice are always in motion and not sitting still. \n\nI hope this helps you.\nTo understand it in  deeper level, you will need to read more on the subjects of bonding, solvent, co-slovent, azeotropi solution, etc.\n\nEnjoy and have fun with chemistry