* Physical Changes: Alter the form or appearance of a substance but don't change its chemical composition.

* Examples: melting ice, cutting paper, crushing a can.

* Chemical Changes: Result in the formation of new substances with different chemical properties.

* Examples: burning wood, rusting iron, baking a cake.

When you flatten something, you're changing its shape and possibly its size, but you're not changing the substance itself. The chemical makeup of the material remains the same.