* Physical Change: A physical change alters the form or appearance of a substance but doesn't change its chemical composition.

* Chemical Change: A chemical change results in the formation of new substances with different chemical properties.

When you cut a circle out of paper, you're simply changing its shape and size. The paper itself remains the same chemically. It's still made of the same cellulose fibers.

Examples of chemical changes: burning paper, rusting metal, cooking food.