Glossary: Matter, Solids, Liquids, and Energy


Glossary of terms involving matter, phases, phase diagrams, and energy.
Browse the glossary using this index

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C

chemical change

a change that results in a substance with a different identity (chemical composition).  Examples include burning, cooking, rusting, decaying, etc.

chemical property

a property or characteristic of a substance having to do with how the atoms and molecules that make up the substance can be combined with or rearranged into other substances.  These properties can only be measured or observed through changes to the identity (chemical composition) of the substance.  Examples include flammability and reactivity.

G

gas

a phase of matter that has an indefinite shape and an indefinite volume.  The atoms or molecules in a gas are not bonded together and are able to move freely.

L

liquid

a phase of matter that has an indefinite shape, but a definite volume.  The atoms or molecules in a liquid are bonded together, but the bonds are continuously breaking and re-forming.

M

matter

anything that has mass and takes up space

P

phase

the physical form of a sample of matter; solid, liquid, gas, or plasma

physical change

a change that alters one or more physical properties of a substance, but does not alter the identity of the substance.  Examples include freezing, boiling, bending, crushing, etc.

physical property

a property or characteristic of a substance that can be measured or observed without changing the identity (chemical composition) of the substance.  Some examples include boiling point, melting point, density, size, shape, etc.

plasma

a phase of matter in which the amount of heat energy available is larger than the ionization energy of the atoms.  This means electrons are continuously escaping and re-attaching, resulting in a sea of highly charged particles.  Plasmas exist only at very high temperatures, such as those found in stars.

S

solid

A phase of matter that has a definite shape and definite volume.  The atoms or molecules in a solid are rigidly bonded together.