Physical change

Physical change is a concept introduced to contrast with the concept of chemical change. A physical change is any change not involving a change in the substance's chemical identity. Matter undergoes chemical change when the composition of the substances changes: one or more substances combine or break apart to form new substances.

Changes are sometimes hard to categorize strictly as physical or as chemical. Dissolving a salt in water involves the breaking of chemical bonds, yet is often described as a physical change. Some teachers hold that a chemical change is a rearrangement of atoms, but many physical changes also involve the rearrangement of atoms. Many chemical changes are irreversible, and many physical changes are reversible, but reversibility is not a certain criterion for classification. Although chemical changes are often recognized by an indication such as odor, color change, production of a precipitate, or production of a gas, every one of these indicators can result from physical change.

Examples of Physical Changes

• Change of state (such as from solid to liquid or from gas to liquid)
• Absorption of water into a towel
• Crumpling a piece of paper
• Pulling copper into a thin wire - a change of shape, but not a change of composition
• Cutting a material such as wood
• Ripping a piece of tin foil
• Breaking glass
• Deflating a Basketball
• Washing Clothes
• Writing on a Sheet of Paper