Physical Properties
Elementary School
Definition
Characteristics of a substance that can be observed or measured without changing what it is, such as mass, colour, density, and state of matter. Physical properties are used to identify and compare substances and do not involve forming a new substance.
Worked examples
Ice has a density of \(0.92 \, \)g/cm\(^3\), melting point of \(0^\circ\)C\(\), and appears colourless and solid.
These can all be observed without changing water into a different substance.
Iron is silver-grey, magnetic, conducts electricity, and has a density of \(7.87 \, \)g/cm\(^3\).
Each property helps identify iron and can be measured without forming a new material.
Common mistakes
- Flammability is a physical property because you can see a substance burn. → Flammability is a chemical property because burning creates new substances (ash, gases). Physical properties don't involve forming new substances; burning does.
- Reactivity with acid is a physical property since the metal's appearance changes. → Reactivity is a chemical property because a new substance forms in the reaction. If a new substance appears, it's a chemical property, not physical.
- Boiling point is not a physical property because the substance changes state. → Boiling point is a physical property; the substance remains the same, only its state changes. Changing state (solid/liquid/gas) doesn't change what the substance is.
Where you'll use it next
You'll use physical properties when separating mixtures (filtration, distillation), identifying unknown substances in lab investigations, and understanding states of matter and phase changes in chemistry and physics.
See also
Reviewed by Pat Cheng, M.Ed. — StudyPug Curriculum Lead · Last updated June 6, 2026