In this deck, we'll explore one of the most fundamental rules in all of physics: the conservation of energy. You'll learn what this principle means, how it applies to closed systems, and why no energy transfer is ever perfectly efficient. We'll also look at ways to reduce wasted energy and how to calculate the efficiency of a device.

The principle of conservation of energy is a simple but powerful idea. It states that energy can be transferred usefully, stored, or dissipated, but it can never be created or destroyed. The total amount of energy in the universe is constant; it just changes form.

To understand energy conservation, physicists often think about 'closed systems'. A closed system is an idealized concept of a system that doesn't interact with its surroundings. No energy or matter can get in or out. For example, the entire universe can be considered a closed system.