8th Grade Physical Science

Vocabulary flashcards for key terms in 8th-grade physical science.

volume

The amount of space taken up by an object.

matter

Anything that has a volume and mass.

mass

The amount of matter in an object.

weight

The measure of the gravitational force on an object.

density

The amount of matter in a given space.

atoms

The smallest units of matter.

protons

Positively charged particles found in the nucleus of atoms.

electrons

Negatively charged particles found around the nucleus of an atom.

nucleus

The part of the atom where its mass is found.

atomic number

The number of protons in an atom.

atomic mass

The total mass of an atom, accounting for protons and neutrons.

groups

The vertical columns on the periodic table.

periods

The horizontal rows on the periodic table.

reactive

Elements in group 1 of the periodic table, which are highly reactive.

chemical formulas

Represent compounds, composed of symbols for elements.

elements

Substances that cannot be broken down into simpler substances.

mixture

A substance that is NOT chemically combined.

chemical bond

The force that holds atoms together in a compound.

freezing

Energy is removed from a liquid and causes the particles to slow down.

boiling

Energy is added to a liquid and causes the particles to speed up.

condensation

Energy is removed from a gas and causes the particles to slow down.

melting

Energy is added to a solid and causes the particles to speed up.

kinetic energy

Energy that depends on mass and speed.

potential energy

Energy that depends on mass and height.

frequency

The number of waves created every second.

amplitude

The maximum extent of a wave's displacement.

light waves

Electromagnetic waves that do not need a medium.

sound waves

Mechanical waves that require a medium.

law of conservation of matter

In a chemical equation, the total mass of reactants equals the total mass of products.

Doppler effect

The change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source.

inertia

The tendency of objects to resist a change in motion.