Introduction to Matter (Book)

A physical change in matter is a change in one or more of matter’s physical properties. Glass breaking is just one example of a physical change. Some other examples are shown in Figure below and in the video below. In each example, matter may look different after the change occurs, but it’s still the same substance with the same chemical properties. For example, smaller pieces of wood have the ability to burn just as larger logs do.

Because the type of matter remains the same with physical changes, the changes are often easy to undo. For example, braided hair can be unbraided again. Melted chocolate can be put in a fridge to re-harden. Dissolving salt in water is also a physical change. How do you think you could undo it?