plastic is a mean of preposition & types down an preposition user that preposition 's size ->  breaking a glass changes the shape of the glass  breaking a glass changes the shape of the glass & size is a mean of physical public ->  breaking a glass changes the physical property of the glass  breaking a glass changes the physical property of the glass & if something undergoes a physical static then the physical article of that something will static -> breaking a glass is an example of a glass undergoing a physical change