04 Thermal Physics

Thermal Physics. In H2 Physics, the everyday concepts of heat and temperature are reexamined. Single-particle mechanics is applied to model an ideal gas, which is one of the simplest many-body systems. A crucial purpose of this section is to connect the microscopic behaviour of individual constituents with the macroscopic properties of the collective system, for learners to simultaneously see the forest and the trees. The strand of energy provides insight into physical processes like melting and boiling for material substances generalised beyond ideal gases. The overlap with what learners might have encountered in chemistry provides opportunities for teachers to discuss cross-curricular connections.

Big Ideas 1. When a substance gains or loses heat, the substance may change its temperature, change its state, change its volume or change to a different substance. The kinetic model allows us to understand the macroscopic properties of matter and changes in its state in terms of its microscopic molecular structure and behavior. 2. Energy may be transferred through all materials and through free space (vacuum). Our understanding of the different mechanisms of heat transfer through different materials enables us to control and make use of heat transfer in many appliances and machines. 3. The internal energy of a body consists of the total kinetic energy and potential energy of the particles in the body. Changes in a body or a substance due to heat gain or heat loss may be explained by the change in its internal energy. 4. Thermodynamics is the study of the relationship involving heat, mechanical work and other aspects of energy and energy transfer. The first law of thermodynamics is a general statement of the law of conservation of energy that includes energy transfer through heat as well as mechanical work. The ideal gas equation gives the relationship of the pressure, volume, temperature, and the number of moles of a gas. This equation allows us to find the state of a gas in any situation.