# Thermal Physics

#### Chapter 11 - Thermal Physics

In the GCE A Levels, we need to understand the difference between the Degrees Celsius scale and the Kelvin scale. This video will discuss the concept of empirical and absolute scales, and briefly explain why we prefer the Kelvin scale and absolute scales in scientific applications.

The Kelvin scale is always 273.15 temperature units larger than the Degrees Celsius scale. In the GCE A Levels, we are required to apply this conversion frequently, but we are also required to understand how this translation was discovered. This video will explain how Lord Kelvin discovered this.

In the GCE A Levels, we must understand that any number of objects in thermal contact will eventually reach thermal equilibrium. This video will discuss how thermal equilibrium is reached between two bodies, via the net flow of heat or thermal energy.

Ideal gases are an important part of thermal physics in the GCE A Levels, and this video will introduce ideal gases together with some key assumptions of their behaviour.

In the GCE A Levels, we have to apply the ideal gas law to solve various problems involving ideal gases. This video will introduce the two variations of this law, which connects the pressure, volume, amount and temperature of the gas.

We describe the pressure of a gas using kinetic theory, by studying the average force exerted by gas particles on a surface. This video will run through the derivation of the expression for this pressure as required by the GCE A Levels.

With the expression for pressure, we can combine this with the ideal gas law to obtain a unique expression for the temperature of an ideal gas. In the GCE A Levels, we need to understand that the thermodynamic temperature of an ideal gas body is directly proportional to its average molecular kinetic energy, and this video will explore this.

The GCE A Levels requires us to understand the concept of specific heat capacity and heat capacity of a substance or object. This video will introduce these concepts and how we can use it to study systems in thermal contact.

The GCE A Levels requires us to understand the concept of specific latent heat and latent heat of a substance or object. This video will introduce these concepts and how we can use it to study systems which undergo a change in state.

The internal energy of an object is the sum of the microscopic potential and kinetic energies of all the particles in the object. The GCE A Levels requires us to understand this and this video will briefly discuss this idea.

One of the most important concepts in the GCE A Levels is the First Law of Thermodynamics. This video will introduce this law, and discuss the analysis and positive conventions of each term – the change in internal energy, heat supplied and work done on the system.

The GCE A Levels requires us to understand five types of thermodynamic processes, including isothermal, adiabatic, isochoric (or isovolumetric), isobaric and cyclic changes. This video will explain what each of these processes mean, and also their implication to the application of the First Law of Thermodynamics.