Physical change
From Wikipedia, the free encyclopedia
A physical change involves the change in a substance that does not involve a chemical reaction, as opposed to a chemical change. Since no reaction occurs, there are no chemical substances present after a physical change that were not there before the change. Because of this, a physical change is often said to be reversible. However, this definition is sometimes misleading, as many physical changes are difficult to reverse (such as cutting paper) and some chemical reactions reverse very easily (see reversible reaction).
Examples of physical change include:
- Change of state (such as solid to liquid)
- Creation or separation of a mixture (including homogeneous mixtures, where the solute may not be visible)
- Physical deformation (cutting, denting, stretching, etc.)
- Change in color by addition of dye
- Substance able to be reversed to prior form
A physical change alters a substance without changing it into another substance. An example of a physical change would be boiling water. The water is converted from liquid to gas form, but is still water both before and after the change.
