IGCSE – Physics- 0625 Thermal physics Part 2 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 1 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 2 6/23/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 3 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 4 Thermal energy or internal energy 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 5 Internal (thermal)energy +Temperature + Heat • Internal Energy • When a substance is heated, its internal or thermal energy increases. • As a substance’s internal energy increases, so will its temperature. The higher the temperature of a substance, the more internal energy it have. As the temperature of a substance is increased, the total energy of the molecules (the internal energy) increases 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 6 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 7 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 8 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 9 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 10 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 11 Internal Energy (thermal energy)& Molecules • The molecules within a substance possess two forms of energy: – Kinetic energy (due to their random motion/vibration). – Potential energy (due to the bonds between the molecules). • Together, these two forms of energy make up the internal (thermal) energy of the substance. • When a substance is heated, that heat will usually cause the kinetic energy of the molecules to increase. • The temperature of the material is related to the average kinetic energy of the molecules. 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 12 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 13 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 14 Question 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 15 Answer • The temperature and internal energy are directly proportional. A decrease in the temperature will result in a proportional decrease in the internal energy • The temperature decrease 10C÷20C = 0.5 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 16 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 17 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 18 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 19 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 20 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 21 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 22 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 23 6/21/2020 IGCSE - Physics - Thermal Physics - Manal Mousa 24