This course is concerned with the study of thermodynamics, which includes the concepts of heat, internal energy and temperature. Thermodynamics is very successful in explaining the bulk properties of matter and the correlation between those properties and the mechanics of atoms and molecules. In general, thermodynamics must concern itself with the physical and chemical transformations of matter in all its forms: solid, liquid, gas and plasma. You may have wondered how a refrigerator cools, what transformations occur in a car engine, or what happens to the kinetic energy of a falling object once it hits the ground? The laws of thermodynamics and the concepts of heat and temperature enable us to answer such practical questions. We start with temperature, which is a central concept in thermodynamics and forms one of the seven basic SI units.