Physics: Topic 1 - Heating Processes

Kinetic particle model and specific heat capacity and Phase changes and energy conservation

Model

A representation that describes or explains the workings within an object, system, or idea.

Kinetic particle model

Proposes that all matter is made of atoms or molecules (particles) that are in constant motion.

Work

Is done when a force is applied to an object and moves it (measured in joules).

Energy

A measure of an object's ability to do work.

Potential energy

Stored energy.

Kinetic energy

Energy of movement.

Heat

The transfer of thermal (Internal) energy from a hotter to colder body.

Temperature

Quantifies how 'hot' or 'cold' something is; related to the thermal energy per molecule (the average KE of individual molecules).

Internal energy

Refers to the total kinetic and potential energy of the particles within a substance.

Heat transfer (general)

The process by which energy is transferred between objects due to a temperature difference.

Conduction

The transfer of heat through matter (solids, liquids, or gases) without bulk motion of the matter; energy transfer from more energetic to less energetic particles due to interaction between them.

Conductors

Materials that conduct heat readily.

Insulators

Materials that are poor thermal conductors.

Thermal conductivity

Describes the ability of a material to conduct heat, measured in watts per metre kelvin (W m⁻¹ K⁻¹).

Convection

A way heat moves through fluids (liquids and gases) where warmer parts rise and cooler parts sink, creating a continuous cycle.

Radiation

The transfer of energy (like from the sun to Earth) over empty space via electromagnetic waves.

Electromagnetic Radiation

Emitted by all objects above absolute zero (0 K or −273°C); its wavelength and frequency depend on the object's internal energy.

Thermal Equilibrium

Occurs when two or more objects in contact no longer exchange heat because they have reached the same temperature.

Specific heat capacity

The amount of heat energy needed to raise the temperature of 1 kilogram of a substance by 1 degree Celsius.

Phase change

When matter changes from one state (solid, liquid, gas, plasma) to another.

Latent heat

The heat required for an object to change phase (melt, boil, freeze, etc.) without any change in temperature.

Specific latent heat

The amount of heat energy required to change the state of one kilogram of a substance without changing its temperature, measured in joules per kilogram (J/kg).

Latent heat of fusion

The amount of energy required to melt a solid.

Latent Heat of Vaporisation

The amount of energy required to change a liquid to a gas.

Evaporation

The process where a liquid turns into a gas at the surface, even without boiling, often causing cooling.

Calorimetry

The scientific method used to measure the amount of heat transferred to or from a substance during a physical or chemical process.

Calorimeter

The device used for measuring thermal energy in calorimetry.

First Law of Thermodynamics

States that energy cannot be created or destroyed, only transformed from one form to another (ΔU = Q + W).

Efficiency (heat engine)

How effectively a heat engine converts heat energy into useful mechanical work.

How do atoms behave when a substance heats up or cools down?

Atoms speed up or slow down, causing their kinetic energy to increase or decrease.

What is the SI unit of temperature?

Kelvin (K).

What are the three ways heat transfer can take place?

Conduction, Convection, and Radiation.

Why are metals good conductors of heat?

They have free electrons that can move easily through the material, quickly carrying thermal energy to cooler areas.

In which states of matter does convection occur?

Liquids and gases (fluids).

Why does temperature remain constant during a phase change?

All the heat energy is used to break bonds between particles, not to raise their kinetic energy.

What happens to the internal energy of a system if heat is added and work is done on the system?

The internal energy of the system increases.

Temperature conversion from Celsius to Kelvin

TK = Tc + 273

Temperature conversion from Celsius to Fahrenheit

Tc = (5/9) x (Tf - 32)

Heat transfer involving specific heat capacity

Q = mcΔT

Latent heat calculation

Q = mL

First Law of Thermodynamics

ΔU = Q + W

Efficiency of heat transfers

Efficiency = (energy output / energy input) x 100%