Thermal Equilibrium and Heat Flow

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Thermal Equilibrium Noun

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[thur-muhl ee-kwuh-lib-ree-uhm]

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Thermal Equilibrium

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The state where objects in contact reach the same temperature, resulting in no net flow of energy between them.

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Example: This diagram shows a hot object (100°) and a cold object (0°) transferring heat until they both reach the same intermediate temperature (50°), called thermal equilibrium.

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Thermal Energy Noun

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[thur-muhl en-er-jee]

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Thermal Energy

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The total internal energy of an object related to the random motion of its atoms and molecules.

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Example: This diagram shows thermal energy moving as heat from a hotter object to a colder object, which is the basis of heat flow.

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Heating Noun

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[hee-ting]

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Heating

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The process by which thermal energy is transferred from a warmer object or region to a cooler one.

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Example: This diagram shows that heating is the transfer of thermal energy, as heat flows from the hot liquid to the cold liquid through the connecting channel.

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Radiation Noun

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[rey-dee-ey-shuhn]

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Radiation

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The transfer of energy through space by electromagnetic waves, such as light and infrared.

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Example: The Sun transfers heat energy to the Earth through space via electromagnetic waves, a process called radiation.

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Conduction Noun

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[kuhn-duhk-shuhn]

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Conduction

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The transfer of thermal energy through direct physical contact between particles of matter.

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Example: Heat conducts from a higher temperature area to a lower one as faster-moving particles collide with and transfer energy to slower-moving particles.

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Convection Noun

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[kuhn-vek-shuhn]

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Convection

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The transfer of heat through the bulk movement of fluids, such as liquids or gases.

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Example: Heat from the flame causes water molecules at the bottom to warm up, become less dense, and rise. Cooler, denser molecules sink, creating a circular flow.

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Electromagnetic Waves Noun

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[ih-lek-troh-mag-net-ik weyvs]

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Electromagnetic Waves

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Waves of energy, such as visible light, that can travel through space and transfer thermal energy.

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Example: This diagram shows the electromagnetic spectrum, a range of waves from high-energy gamma rays to low-energy radio waves, including the infrared waves that transfer heat.

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Thermal Conductor Noun

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[thur-muhl kuhn-duhk-ter]

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Thermal Conductor

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A material that allows thermal energy to transfer easily and does not significantly resist changes in temperature.

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Example: This image shows a rod acting as a thermal conductor, transferring heat energy from the hot flame on one end to the cooler end held by the hand.

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Thermal Insulator Noun

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[thur-muhl in-suh-ley-ter]

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Thermal Insulator

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A material that resists the transfer of thermal energy and changes in temperature.

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Example: This diagram shows a material wrapped around a cup of warm water. This material acts as a thermal insulator, slowing down the flow of heat.

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Fluid Noun

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[floo-id]

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Fluid

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A substance, such as a liquid or a gas, that has no fixed shape and is able to flow.

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Example: This diagram shows particles in a liquid, a type of fluid. The particles are randomly arranged and can move, allowing heat transfer through convection.