Science · Grades 3–7
Matter and changes · quick reference
A change of state is physical. Heating does not automatically mean a new substance has formed.
Key terms at a glance
Solid
A state of matter with a definite shape and volume under ordinary classroom conditions.
Liquid
A state of matter with a definite volume that takes the shape of its container.
Gas
A state of matter that expands to fill the available container.
Melting
A change from solid to liquid.
Freezing
A change from liquid to solid.
Condensation
A change from gas to liquid.
Evaporation
The escape of particles from a liquid surface into the gas phase.
Sublimation
A direct change from solid to gas.
Deposition
A direct change from gas to solid.
Physical change
A change in form or state without forming a different chemical substance.
Chemical change
A change that forms one or more different chemical substances.
Mixture
A combination of substances not all chemically bonded into a single pure substance.
Solution
A homogeneous mixture in which components are dispersed at molecular or ionic scale.
Solute
The substance described as being dissolved in a solution.
Solvent
The dissolving medium in a solution.
Filtration
Separating insoluble particles from a fluid using a porous barrier.
Density
Mass per unit volume.
Mass
A measure of an object's inertia, expressed in kilograms in SI.
Volume
The three-dimensional space occupied by an object or substance.
Conductor
A material through which electricity or heat can pass relatively readily.
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · teacher review required. Grade bands are approximate, not official curriculum alignment.