MYP Physics Heat, Light and Sound Key Definitions

Atmospheric pressure is the pressure exerted by the weight of the air above a surface.

Boyle’s law states that pressure is inversely proportional to volume at constant temperature.

Describes a solid that breaks or shatters when deformed, with little permanent bending.

The random jittery motion of small visible particles (like smoke or pollen) caused by countless random collisions with much smaller molecules in a gas or liquid.

Conduction is the transfer of heat through particle collisions.

Convection is the transfer of thermal energy through the movement of fluid particles, driven by differences in density.

Density is the amount of mass per unit volume of a substance.

Describes a material that can be stretched into a wire without breaking.

Evaporation is a phase change in which a liquid turns into a gas at temperatures below its boiling point.

Heat is energy transferred between objects due to a difference in temperature.

The movement of thermal energy from one object or region to another due to a temperature difference.

Kinetic energy is the energy an object possesses due to its motion.

A model of matter (especially gases) in which particles are in constant random motion and macroscopic properties like temperature and pressure arise from their collisions.

Describes a material that can be permanently deformed under compression (e.g., hammered or rolled) without breaking.

A phase diagram shows which state of matter exists under different temperature and pressure conditions.

The liquid portion of the blood

Pressure is force exerted per unit area on a surface.

Transfer of heat through infrared radiation, where the body radiates heat into the surroundings or absorbs heat from warmer objects or the sun.

Specific heat capacity is the energy required to raise the temperature of 1 kg of a substance by 1 °C (or 1 K).

A physical form of a substance (such as solid, liquid, gas, or plasma) determined by how its particles are arranged and how strongly they interact.

A change of state in which a substance transitions directly from solid to gas without passing through the liquid state.

Temperature is a measure of how hot an object is, linked to the average kinetic energy of its particles.

The branch of physics that studies temperature, heat energy, and how energy transfers due to temperature differences, often using particle (kinetic) models of matter.

Electromagnetic radiation emitted by matter due to its temperature, transferring energy without needing contact or a material medium.