Grade 7 Science – Heat & Particle Theory Vocabulary

Vocabulary flashcards covering the fundamental concepts of particle theory, states of matter, and thermal energy for Grade 7 Science.

Thermal energy

The total energy of all the particles in a substance.

Temperature

The average kinetic energy of the particles in a substance.

Kinetic energy

The energy of motion possessed by particles, which increases as particles are heated.

Particle theory of matter

The theory stating that all matter is made of particles, particles are always moving, there are spaces between them, they move faster when heated, and different substances have different particles.

Thermal expansion

The occurrence where materials expand when heated because particles move faster and spread farther apart, although the particles themselves do not get bigger.

Heat transfer

The process by which energy moves from warmer objects to cooler objects.

Solid

A state of matter where particles have specific arrangements and move slower than in liquids or gases.

Liquid

A state of matter where particles have more space and movement than in a solid, and loses energy during freezing.

Gas

A state of matter where particles expand and take up more space when heated, often causing an increase in pressure.

Freezing

The change of state from a liquid to a solid that occurs when particles lose energy and motion slows down.

Melting

The change of state from a solid to a liquid.

Evaporation

The change of state from a liquid to a gas.

Condensation

The change of state from a gas to a liquid.

Air pressure

The force exerted by gas particles that can increase inside a container when temperature increases and particles move faster.