2013-3-1 Introduction Q:Refrigerator open in a well-sealed and well-insulated room.Will the temperature increase,stay the same,or go down? A:Considering the room as the system(adiabatic)the only Room energy consumed by the device to heat,the room temperature will rise. Energy cannot be created or destroyed A refrigerator operating with its door open in a well-sealed and well- insulated room 2-5 Review:Forms of Energy >Energy exists in numerous forms:thermal mechanical,kinetic,potential,electric, magnetic,chemical,and nuclear,and their sum constitutes the total energy,E of a system. sony vin the change >Macroscopic forms of energy:e.g.,kinetic and potential energies. Microscopic forms of energy:relate ed to the ofe molecl structure of a system and the degree mofnerfe 2-6 32013-3-1 3 A refrigerator operating with its door open in a well-sealed and well￾insulated room Introduction Q: Refrigerator open in a well-sealed and well-insulated room. Will the temperature increase, stay the same, or go down? A: Considering the room as the system (adiabatic) the only energy interaction involved is the electrical energy crossing the system boundary and entering the room. As a result of the conversion of electric energy consumed by the device to heat, the room temperature will rise. 2-5 Energy cannot be created or destroyed Review: Forms of Energy ¾ Energy exists in numerous forms: thermal, mechanical, kinetic, potential, electric, magnetic, chemical, and nuclear, and their sum constitutes the total energy, E of a system. ¾ Thermodynamics deals only with the change of the total energy. ¾ Macroscopic forms of energy: e.g., kinetic and potential energies. ¾ Microscopic forms of energy: related to the molecular structure of a system and the degree of the molecular activity. 9 Internal energy, U: The sum of all the microscopic forms of energy. 2-6