PHYSICAL CHANGES:

Physical changes come in many forms. It can be a change in the shape or appearance of an object, like crumpling a piece of paper, or cutting, bending, or dissolving something.

Since objects do not become a different substance during a physical change, it is usually easy to reverse the change. For example, if you dissolve sugar in the water you can easily reverse the change by evaporating the water from the solution. When all the water evaporates, sugar crystals will be left behind.

CHEMICAL CHANGES:

Anytime a new substance is made, a chemical change takes place. Usually, two or more materials are combined and a new substance is formed.

Since chemical changes make new substances, most of them cannot easily be undone. For example, when you burn wood, you can’t really turn the gases back into a log very easily.