Examples of Physical Changes

They are distinct from chemical changes in several ways

Examples of 10 different physical changes

Illustration: Hugo Lin, © ThoughtCo., 2018

Physical changes involve states of matter and energy. No new substance is created during a physical change, although the matter takes a different form. The size, shape, and color of matter may change. Physical changes occur when substances are mixed but don't chemically react.

How to Identify a Physical Change

One way to identify a physical change is that such a change may be reversible, especially a phase change. For example, if you freeze water into an ice cube, you can melt it into the water again. Ask yourself:

  • Is the change reversible? Not all physical changes are easy to reverse.
  • Was there a color change (with exceptions), bubble formation, or formation of a precipitate? These are all signs of a chemical change, not a physical change.
  • Is the chemical identity of the end product the same as it was before the change? If the answer is yes, it's a physical change. If the answer is no, it's a chemical change.

Examples of Physical Changes

  • Crushing a can
  • Melting an ice cube
  • Boiling water
  • Mixing sand and water
  • Breaking a glass
  • Dissolving sugar and water
  • Shredding paper
  • Chopping wood
  • Mixing red and green marbles
  • Sublimation of dry ice
  • Crumpling a paper bag
  • Melting solid sulfur into liquid sulfur. This is an interesting example since the state change does cause a color change, even though the chemical composition is the same before and after the change. Several nonmetals, such as oxygen and radon, change color as they change phase.
  • Chopping an apple
  • Mixing salt and sand
  • Filling a candy bowl with different candies
  • Vaporizing liquid nitrogen
  • Mixing flour, salt, and sugar
  • Mixing water and oil

Indications of a Chemical Change

Sometimes the easiest way to identify a physical change is to rule out the possibility of a chemical change. There may be several indications that a chemical reaction has occurred. Note: It's possible for a substance to change color or temperature during a physical change.

  • Evolving bubbles or releasing gas
  • Absorbing or releasing heat
  • Changing color
  • Releasing an odor
  • Inability to reverse the change
  • Precipitation of a solid from a liquid solution
  • Formation of a new chemical species. This is the best and surest indicator. A change in the chemical properties of the sample may indicate a chemical change (e.g., flammability, oxidation state).