Definition

1. Noun:
   • A hypothetical device that operates indefinitely without an external energy source: A "perpetual motion machine" is a theoretical machine that can perform work forever without requiring any input of energy. Its existence is considered impossible according to the fundamental laws of physics, specifically the law of conservation of energy.

Usage Examples

• Noun:
  • The inventor claimed to have built a perpetual motion machine, but scientists dismissed it as a fraud.
  • Designing a true perpetual motion machine would violate the first law of thermodynamics.
  • The concept of a perpetual motion machine has fascinated and frustrated inventors for centuries.

Advanced Usage

• "Perpetual motion machine of the first kind": A hypothetical machine that produces work without any energy input, directly violating the conservation of energy.

  • His design was criticized for being nothing more than a proposed perpetual motion machine of the first kind.

• "Perpetual motion machine of the second kind": A hypothetical machine that spontaneously converts thermal energy into mechanical work, violating the second law of thermodynamics.

  • A device that extracts energy from ambient heat to do work would be a perpetual motion machine of the second kind.

Variants and Related Words

• Perpetual motion (noun phrase): The concept of motion that continues forever without an energy source.
  • The idea of perpetual motion is a classic example of a scientific impossibility.

Synonyms

• Impossible machine: A machine that cannot exist according to known physical laws.
• Over-unity device: A term sometimes used in pseudoscience for a device claimed to produce more energy than it consumes.

Related Phrases

• To seek/search for perpetual motion: To attempt the impossible task of creating such a machine.
  • He wasted his fortune seeking perpetual motion.

Related Idioms

• A perpetual motion machine: Often used metaphorically to describe a theoretical, self-sustaining, or impossibly efficient system.
  • The proposed economic model was dismissed as a perpetual motion machine, beautiful in theory but impossible in practice.
  • Trying to get a toddler to nap is like trying to build a perpetual motion machine.

Noun

1. a machine that can continue to do work indefinitely without drawing energy from some external source; impossible under the law of conservation of energy