6.1 BASIC PRINCIPLES AND FLUIDS Heat pervades our lives: heating and cooling systems are present in our homes, schools and workplaces to control the temperature and to keep us as comfortable as possible. Heat 1 DO Some materials are better conductors of heat than others: metals are considered good conductors. Why? 1 Energy transfer Heat is present only when there is energy transfer: for example, if we place a very hot mug of coffee with a temperature of 80°C on the kitchen table, after a while, both the coffee and the mug will and will reach room temperature. The coffee and the mug have transferred heat to the surrounding air. The fact that the mug and the coffee lower their temperature is a sign that the average kinetic energy of their particles is decreasing, and they are both losing energy which is transferred to the colder surroundings. cool down eventually Heat We refer to this transfer of energy from the coffee and the mug to the surrounding air as , that is to say the transfer of energy from a hot object to a colder object. , an object increases its temperature by gaining energy in the form of heat from its surroundings. Both the and the cooling down of objects work in the same way. heat Conversely warming up Thermodynamics is the of physics that deals with the relationships between heat and other forms of energy. It developed in the 19th century when scientists were first discovering how to build and operate steam engines. In particular, it describes how thermal energy is converted into and from other forms of energy and how it affects matter. is the energy a substance or system has its temperature, i.e. the energy of moving or vibrating molecules. Thermodynamics branch 1 Thermal energy due to MORE Thermal energy, also called heat energy, is produced when a rise in temperature causes atoms and molecules to move faster and collide with each other. 1 The first law of thermodynamics The states that heat is a form of energy, and that thermodynamic processes are therefore subject to the principle of . This means that heat energy cannot be created or destroyed; it can, however, be transferred from one location to another and converted into and from other forms of energy. first law of thermodynamics conservation of energy