What does conservation of energy mean in a closed system?

Get ready for the NCEA Level 1 Energy Test. Utilize flashcards and multiple choice questions with clear explanations and hints. Prepare for success!

In a closed system, energy cannot be created or destroyed; it can only change from one form to another, and the total amount of energy stays the same. This means energy can shift between kinetic energy, potential energy, thermal energy, light, sound, and so on as things move and interact, but when you add up all these forms, the total remains constant.

Think of a pendulum: as it swings, gravitational potential energy turns into kinetic energy and back again. If the track is frictionless, the total energy at any moment is the same, just redistributed between forms. In real life, some energy may become heat due to friction, but that heat is still part of the system’s total energy.

The other ideas don’t fit because energy isn’t magically created or destroyed, and energy conservation isn’t limited to mechanical systems—it's about all forms of energy within a closed system.