| Term | Definition |
|---|---|
| Thermal energy | Thermal energy is the internal energy of an object due to the kinetic energy of its atoms and/or molecules. |
| Solid | firm and stable in shape; not liquid or fluid. |
| Liquid | having a consistency like that of water or oil, i.e., flowing freely but of constant volume. |
| Gas | an air like fluid substance which expands freely to fill any space available, irrespective of its quantity. |
| Plasma | a fourth state of matter distinct from solid or liquid or gas and present in stars and fusion reactors; a gas becomes a plasma when it is heated until the atoms lose all their electrons, leaving a highly electrified collection of nuclei and free electrons |
| Colloid | a homogeneous, noncrystalline substance consisting of large molecules or ultra-microscopic particles of one substance dispersed through a second substance. Colloids include gels, sols, and emulsions; . |
| Phase change | The states in which matter can exist: as a solid, liquid, or gas. When temperature changes, matter can undergo a phase change, shifting from one form to another. |
| Particle | a tiny or very small bit: |
| Melting point | the temperature at which a solid substance melts or fuses. |
| Freezing point | the temperature at which a liquid freezes: The freezing point of water is 32°F, 0°C. |
| Boiling point | the temperature at which the vapor pressure of a liquid is equal to the pressure of the atmosphere on the liquid, equal to 212°F (100°C) for water at sea level. |
| Evaporation | the act or process of evaporating. liquid to gas |
| Condensation | the state of being condensed. |
| Volume | the amount of space, measured in cubic units, that an object or substance occupies. |
| Mass | the quantity of matter as determined from its weight or from Newton's second law of motion. |
| Density | the state or quality of being dense; compactness; closely set or crowded condition. |
| Pure substance | A material that is composed of only one type of particle; examples of a pure substance include gold, oxygen and water. |
| Atom | the smallest component of an element |
| Molecule | the smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound. |
| Element | the smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound. |
| Compound | a pure substance composed of two or more elements whose composition is constant. |
| Extended structure | |
| Physical change | a usually reversible change in the physical properties of a substance, as size or shape |
| Chemical change | a usually irreversible chemical reaction involving the rearrangement of the atoms of one or more substances and a change in their chemical properties or composition, resulting in the formation of at least one new substance |
| Natural resource | the natural wealth of a country, consisting of land, forests, mineral deposits, water, etc. |
| Synthetic material | Something made of artificial material, not natural items, can be described as synthetic. |
