ICSE Class VIII Physics: Matter Lecture Notes

Vocabulary-style flashcards covering the Kinetic Theory of Matter, phase changes, thermal mechanics, and states of matter based on the ICSE Class VIII Physics Specimen Challenge Worksheet.

Condensation

The process by which a gas or vapour changes into a liquid state upon the extraction or reduction of thermal energy (cooling).

Latent heat of fusion

The thermal energy consumed during the transition of a substance from solid to liquid to overcome intermolecular forces without increasing the average kinetic energy or temperature.

Diffusion

The process where particles move randomly into inter-particle spaces to distribute themselves uniformly, powered by the continuous random motion of matter.

Brownian Motion

The continuous, random motion of suspended particles as discovered by Robert Brown, which validates the particle theory of matter.

Compressibility of Gases

The ability of gases to be forced much closer together under external pressure because their inter-particle space is exceptionally large and intermolecular forces are negligible.

Evaporation

A surface phenomenon where molecules escape from the liquid surface spontaneously at any temperature below the boiling point; it is highly accelerated by wind speed.

Boiling

A bulk phenomenon occurring throughout the entire volume of a liquid at a specific constant temperature, independent of wind speed.

Force of Cohesion

The force of attraction between molecules of the same substance, such as water droplets sticking together.

Force of Adhesion

The force of attraction between molecules of different substances, such as glue sticking to paper.

Sublimation

The direct transition of a solid into a gas without passing through the liquid phase, involving an endothermic process where heat is absorbed.

Deposition (Desublimation)

The direct transition of a gas into a solid without passing through the liquid phase, involving an exothermic process where heat is released.

Plasma State

A state of matter consisting of ionized atoms with extremely high kinetic energy, found in stars, the Sun, and lightning.

Bose-Einstein Condensate (BEC)

A state of matter existing near Absolute Zero where particles have virtually zero kinetic energy and condense into a single collective super-atom.

Specific Latent Heat ($L$)

The quantity of heat absorbed or released during a state change per unit mass ($m$), expressed in the SI unit $\text{Joules per kilogram}$ ($J/kg$).

Specific Latent Heat of fusion of ice

$$336 \times 10^3 \text{ J/kg}$$

Specific Latent Heat of vaporization of water

$$2260 \times 10^3 \text{ J/kg}$$

Convection

A mechanism of heat transfer in liquids where heated molecules expand, become less dense, and rise, creating a continuous cycle of bulk movement.

Absolute Zero

The theoretical temperature of $0 \text{ K}$ or $-273.15^{\text{o}}C$ at which all thermal energy is extracted and atomic movement ceases completely.

Wetting of a surface

A condition occurring when the Force of Adhesion is dominant, causing a liquid to spread out rather than form beads.