Welcome to ME 210, Thermodynamics I. I am Professor Hale. Thermodynamics is the science of energy: heat, work, and the rules that govern them. Engineers use it to design engines, batteries, refrigerators, and power plants. In this lecture we do three things. We define a system. We name the kinds of energy. And we write the first law for a closed system. I will speak slowly. When I write a symbol, I will also say the word in English.