Thermal Physics

Non-metals are usually poor conductors and are known as insulators.

When a body changes state, energy goes towards making the molecules more free from each other rather than increasing their kinetic energy.

Gas molecules move faster and further apart, leading to the greatest relative order of magnitude of expansion.

The temperature of a gas is related to the average kinetic energy of its molecules; higher temperature means greater average kinetic energy and faster average speed.

Evaporation can happen at any temperature and only occurs at the surface of the liquid, while boiling occurs throughout the liquid at a specific temperature.

Evaporation cools the liquid because the remaining molecules have a lower average kinetic energy.

Molecules are close together in a random arrangement with weaker intermolecular forces than solids, allowing them to move around each other.

Freezing is when the molecules in a liquid slow down enough that their attractions cause them to arrange themselves into fixed positions, becoming solid.

Fixed points are used to calibrate thermometers, such as the melting point and boiling point of water on the Celsius scale.

Condensation is when some molecules in a gas do not have enough energy to remain separate, forming bonds and becoming liquid.

Convection occurs when molecules in a fluid with high thermal energy move to an area with low thermal energy, causing less dense fluid to rise and denser fluid to fall.

Sensitivity is the change in length per change in temperature, and it can be increased by using a bigger bulb or a narrower bore.

Melting and boiling occur when energy is added to a body without a change in temperature.

Gas molecules exert pressure due to collisions with the walls of the container, changing direction and momentum upon rebounding.

Black bodies with a dull texture are the best absorbers and emitters of radiation.

Increase temperature, increase surface area, and use draught to remove molecules before they return to the liquid.

Gas molecules are far apart in a random arrangement with negligible intermolecular forces, moving quickly in all directions.

Thermal energy is transferred by infrared radiation, which does not require a medium.

Evaporation is the escape of molecules with higher energy from the surfaces of liquids.

If the temperature increases at constant volume, the pressure increases because molecules move faster and collide harder and more frequently with the walls.

Specific latent heat is the amount of energy needed to change the state of 1 kg of a substance.

The liquid absorbs energy from the body to continue evaporating, which cools the body.

Thermal energy in solids and liquids is transferred by conduction.

The higher the temperature and the greater the surface area of a body, the more infrared radiation is emitted.

The molecules vibrate more but stay in place, resulting in a small relative order of magnitude of expansion.

Metals are good conductors because free electrons can move among positively charged ions, transferring heat energy.

As temperature rises or falls, the liquid expands or contracts, and the amount of expansion can be matched to temperature on a scale.

ΔE = m × c × ΔT, where ΔE is the change in thermal energy, m is mass, c is specific heat capacity, and ΔT is the change in temperature.

If the volume increases at constant temperature, the pressure decreases because molecules collide less frequently with the walls.

The formula is E = m × l, where E is the energy in joules, m is the mass in kilograms, and l is the specific latent heat in J/kg.

A liquid expands more than a solid when heated because the intermolecular forces are less.

Examples of convection include water boilers and hot air balloons.

Range is the difference between maximum and minimum temperatures, and it can be increased by using a wider bore or a longer stem.

The melting point is the temperature at which a given solid will melt when heated.

Molecules are close together in a regular pattern with strong intermolecular forces of attraction, vibrating but unable to move about.

The equation is pV = constant, where p is the pressure in Pascals and V is the volume in cubic meters.

A thermocouple contains two different metals that meet, and the temperature difference between them causes a tiny voltage that makes a current flow.

Specific heat capacity is the amount of energy required to raise the temperature of 1kg of a substance by 1 °C.