Heat Flow Within Earth

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Terawatt Noun

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[ter-uh-wot]

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Terawatt

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A unit of power equal to one trillion (10^12) joules per second, used to measure large-scale energy flow.

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Example: This diagram shows how the flow of water in a hydroelectric dam spins a turbine and generator to produce electricity.

Front

Conduction Noun

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[kuhn-duhk-shuhn]

Back

Conduction

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The transfer of heat through a material by direct molecular contact, without the bulk movement of the material itself.

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Example: This diagram shows that heat conduction is the transfer of thermal energy between neighboring particles; high-energy particles collide with low-energy particles, passing heat along.

Front

Convection Noun

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[kuhn-vek-shuhn]

Back

Convection

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The transfer of heat through the physical movement of fluids or other flowing materials, like gases, liquids, or the mantle.

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Example: Heat from below causes water to become less dense and rise. As it cools at the surface, it becomes denser and sinks, creating a circular convection current.

Front

Radiation Noun

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[rey-dee-ey-shuhn]

Back

Radiation

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The transfer of heat energy through space via electromagnetic waves, requiring no medium for its propagation.

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Example: This diagram shows how the Sun sends heat energy to the Earth through space in the form of electromagnetic waves, which is called radiation.

Front

Lithosphere Noun

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[lith-oh-sfeer]

Back

Lithosphere

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The cold, rigid outer layer of the Earth, comprising the crust and uppermost mantle, which is broken into tectonic plates.

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Example: This map shows the Earth's lithosphere is not one solid piece, but is broken into large sections called tectonic plates that constantly move.

Front

Thermal Conductivity Noun

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[thur-muhl kon-duhk-tiv-i-tee]

Back

Thermal Conductivity

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An intrinsic property of a material that quantifies its ability to transfer or conduct heat through it.

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Example: This diagram shows how thermal conductivity works: high-energy particles in a hotter area collide with low-energy particles in a cooler area, transferring heat.

Front

Seismic Waves Noun

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[sahyz-mik weyvs]

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Seismic Waves

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Waves of energy that travel through Earth's layers, resulting from earthquakes, explosions, or volcanic activity.

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Example: This diagram shows a cutaway of the Earth where an earthquake starts at the 'Focus'. The energy released travels outwards in all directions as 'Seismic Waves'.

Front

P waves Noun

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[pee weyvs]

Back

P waves

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A type of seismic compression wave that travels through all parts of the Earth, including both solid and liquid layers.

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Example: This image shows that P waves are compressional waves, like pushing a Slinky, where particles move back and forth in the same direction the wave travels.

Front

S waves Noun

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[es weyvs]

Back

S waves

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A type of seismic transverse wave that oscillates perpendicularly to its direction of travel and can only pass through solid materials.

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Example: This image shows a transverse wave, like an S wave, where particles (the rope) move up and down, perpendicular to the direction the wave travels.

Front

Refraction Noun

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[ri-frak-shuhn]

Back

Refraction

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The change in direction, or bending, of a wave as it passes from one medium to another with different properties.

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Example: When a wave, like light or a seismic wave, passes from one material (medium) into another, its path bends. This bending is called refraction.