Definition

1. Noun:
   • A state in which all parts of a system are at the same temperature: Thermal equilibrium describes a condition where there is no net flow of thermal energy (heat) between different regions or components within a system because they have equalized their temperatures.

Usage

• Thermal equilibrium is a fundamental concept in thermodynamics. It is the state a system reaches over time when it is isolated from external temperature influences. Once achieved, the system's macroscopic properties, like temperature, remain constant.
• This term is used to describe the final, balanced state of a system. For example, when a hot object is placed in a cold room, they will eventually reach thermal equilibrium with each other and the surrounding air.

Examples

• Noun:
  • After the ice cube melted, the water in the glass achieved thermal equilibrium with the room.
  • The experiment requires the two metal blocks to be in thermal equilibrium before we can measure the heat transfer.
  • In a vacuum flask, the inner and outer walls are designed to avoid reaching thermal equilibrium with the environment quickly.

Advanced Usage

• "To be in thermal equilibrium with": This phrase describes the relationship between two or more systems or objects.
  • For an accurate reading, the thermometer must be in thermal equilibrium with the substance it is measuring.
• The Zeroth Law of Thermodynamics formalizes the concept of thermal equilibrium, stating that if two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.

Variants and Related Words

• Equilibrium (n): A state of balance between opposing forces or influences. Thermal equilibrium is a specific type of equilibrium.
• Thermal (adj): Relating to heat or temperature.
• Thermodynamic equilibrium (n): A more comprehensive state of equilibrium that includes not just thermal, but also mechanical and chemical balance.

Synonyms

• Heat balance: A state where heat input equals heat loss, often used in engineering contexts.
• Temperature equilibrium: A less common but descriptive synonym emphasizing the equal temperature condition.

Related Concepts (Not Phrasal Verbs or Idioms)

• Heat transfer: The movement of thermal energy from a hotter object to a colder one, which ceases at thermal equilibrium.
• Isolated system: A system that does not exchange energy or matter with its surroundings, often discussed in relation to achieving equilibrium.

Noun

1. a state in which all parts of a system are at the same temperature