Last Minute Lecture

Energy, Work & the First Law Explained | Chapter 19 of University Physics Chapter 19 establishes how heat and work transfer energy into and out of a system and unifies them through the First Law of Thermodynamics. You’ll learn how to track internal energy changes, interpret p–V diagrams, and distinguish the major thermodynamic processes that govern ideal gases. Watch the full video summary here for detailed explanations and examples. Thermodynamic Systems & Processes A thermodynamic system is the specific collection of matter under study, while the surroundings encompass everything else. A thermodynamic process describes how the system’s state variables—temperature (T), pressure (p), volume (V), and internal energy (U)—change when heat or work crosses the boundary. Heat & Work Heat (Q) is energy transferred due to temperature difference: positive when entering the system, negative when leaving. Work (W) is energy transfer via macroscopic forces: positive w...

Heat, Engines & Entropy Explained | Chapter 20 of University Physics Chapter 20 introduces the Second Law of Thermodynamics and explores how it determines the direction of natural processes. You’ll learn the difference between reversible and irreversible processes, how heat engines and refrigerators operate, and why entropy—a measure of disorder—always increases in real systems. Watch the full video summary here for step-by-step explanations and examples. Reversible vs Irreversible Processes Reversible processes are ideal, quasi-static, and maintain equilibrium at each step. In contrast, irreversible processes —such as spontaneous heat flow, friction, and free expansion—occur in one direction and generate entropy. Real-world systems are inherently irreversible, highlighting the fundamental “arrow of time.” Heat Engines Heat engines convert thermal energy into mechanical work by absorbing heat Q H from a hot reservoir, doing work W , and releasing residual heat Q C t...

Chapter 8: Introduction to Metabolism — Energy, ATP, and Enzymes Explained | Campbell Biology Summary Welcome to Last Minute Lecture! This post summarizes Chapter 8 of Campbell Biology , focusing on metabolism—the chemical reactions that power life. Discover how cells manage energy, the significance of ATP, and the remarkable role of enzymes in controlling biological processes. Watch the full video summary below and subscribe for more textbook chapter breakdowns! Introduction: What Is Metabolism? Metabolism encompasses all the chemical reactions within an organism. These reactions are organized into metabolic pathways, which either break down molecules to release energy (catabolic pathways) or build complex molecules by consuming energy (anabolic pathways). Understanding metabolism is fundamental for grasping how life is sustained at the molecular level. Energy Transformations and the Laws of Thermodynamics Energy Types: Kinetic energy involves movement (including th...