This lecture provides a comprehensive overview of fundamental concepts in relativity and thermodynamics. It begins with an introduction to special relativity, discussing inertial reference frames and the implications of Newton's laws in these frames. The instructor explains the principles of time dilation and length contraction, illustrated with examples involving muons and the Lorentz transformations. The lecture transitions to thermodynamics, covering the first and second laws, the behavior of ideal gases, and the significance of specific heats. The instructor elaborates on the zeroth law of thermodynamics, which establishes the concept of temperature, and discusses phase transitions and latent heat. The lecture concludes with an exploration of thermal engines, emphasizing the Carnot cycle and the efficiency of heat engines. Throughout, the instructor engages with conceptual questions to reinforce understanding, making complex topics accessible and relatable.