Thermal Energy and Heat

Front

Reflection Noun

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[ri-flek-shun]

Back

Reflection

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The bouncing of a wave off a surface that it cannot pass through, which does not change its speed or frequency.

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Example: This diagram shows how a white surface reflects incoming light and heat energy, while a black surface absorbs it, demonstrating thermal reflection.

Front

Refraction Noun

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[ri-frak-shun]

Back

Refraction

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The bending of a wave as it enters a new medium at an angle, which is caused by a change in speed.

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Example: A ray of light bends as it passes from a less dense medium (air) to a more dense medium (glass), changing its direction.

Front

Diffraction Noun

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[dih-frak-shun]

Back

Diffraction

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The bending of a wave as it moves around an obstacle or passes through a narrow opening, changing its direction.

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Example: This diagram shows how sound waves bend, or diffract, as they pass through a doorway, allowing someone to hear around a corner.

Front

Interference Noun

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[in-ter-feer-uhns]

Back

Interference

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The phenomenon occurring when two or more waves overlap and combine while occupying the same region of space.

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Example: This diagram shows two waves moving toward each other and combining. Their amplitudes add up, creating a single, larger wave, demonstrating constructive interference.

Front

Constructive Interference Noun

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[kon-struhk-tiv in-ter-feer-uhns]

Back

Constructive Interference

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A type of interference where two or more waves combine to produce a resulting wave with a larger displacement or amplitude.

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Example: When waves from two sources overlap, their crests can add together, creating a bigger wave. The image shows these points of constructive interference.

Front

Destructive Interference Noun

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[di-struhk-tiv in-ter-feer-uhns]

Back

Destructive Interference

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A type of interference where two or more waves combine to produce a resulting wave with a smaller displacement or amplitude.

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Example: This diagram shows two waves (A and B) that are perfectly out of phase. When they combine, their crests and troughs cancel each other out, resulting in zero amplitude (A+B).

Front

Standing Wave Noun

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[stan-ding weyv]

Back

Standing Wave

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A wave that appears to stay in one place, formed by the interference between a wave and its own reflection.

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Example: This image shows a standing wave created by shaking a rope, with labeled nodes (points of no motion) and antinodes (points of maximum motion).

Front

Node Noun

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[nohd]

Back

Node

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A point on a standing wave with zero displacement from the rest position, resulting from complete destructive interference between waves.

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Example: This diagram illustrates a node as a point of minimum displacement on a standing wave, a concept from general wave physics.

Front

Antinode Noun

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[an-tee-nohd]

Back

Antinode

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A point on a standing wave midway between two nodes that represents the position of maximum displacement, crest, or trough.

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Example: This diagram shows antinodes as the points of maximum vibration on a standing wave, but it does not relate this wave concept to thermal energy.

Front

Sound Waves Noun

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[sound weyvz]

Back

Sound Waves

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Longitudinal waves consisting of alternating compressions and rarefactions that require a medium through which to travel from a source.

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Example: A vibrating tuning fork creates compressions and rarefactions in the air, forming a longitudinal sound wave that travels to the ear.