Waves & Information
24 concepts · ordered by prerequisite depth
Waves are disturbances that transfer energy from one place to another without transporting matter. This topic covers the properties shared by all waves — wavelength, frequency, amplitude, and speed — as well as behaviors like reflection, refraction, diffraction, and interference. Students explore both mechanical waves (such as sound and water waves) and electromagnetic waves (such as light, radio, and X-rays). The electromagnetic spectrum is introduced as a continuum of waves with different frequencies and energies, each with distinct applications in communication, medicine, and technology. Students also learn how digital signals encode and transmit information. Understanding waves is essential for making sense of phenomena from musical instruments to fiber-optic internet to medical ultrasound, and it provides a foundation for modern physics topics like quantum mechanics.
Suggested order: Begin with the basic properties of waves using mechanical examples like springs and sound, then study wave behaviors such as reflection and refraction, and finally explore the electromagnetic spectrum and information transfer.
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Waves
A disturbance that transfers energy and information through space or a medium without permanently displacing the matter it travels through.
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Frequency
The number of complete wave cycles passing a fixed point per second, measured in hertz (Hz).
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Wavelength
Wavelength is the distance between two consecutive identical points on a wave, such as from one peak to the next peak or one trough to the next trough.
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Continue from here · 21 concepts
Amplitude
The maximum displacement of a wave from its equilibrium (rest) position, measuring the wave's strength or intensity.
Longitudinal Wave
A wave in which the particles of the medium oscillate parallel to the direction of wave propagation, creating alternating regions of compression (high pressure) and rarefaction (low pressure).
Reflection
The change in direction of a wave at a boundary so that it returns into the original medium.
Transverse Wave
A wave in which the particles of the medium oscillate perpendicular to the direction of wave propagation.
Diffraction
The spreading of a wave as it passes through a gap or around the edge of an obstacle.
Electromagnetic Waves
Transverse waves consisting of oscillating electric and magnetic fields that are perpendicular to each other and to the direction of propagation.
Intensity
Wave intensity is the power carried by a wave through each unit of area.
Interference
The phenomenon that occurs when two or more waves overlap in space, combining their displacements at every point according to the principle of superposition.
Period
The time required for one complete cycle of a repeating wave or oscillation to occur, measured in seconds.
Sound
A longitudinal mechanical wave that travels through a medium (solid, liquid, or gas) via alternating compressions and rarefactions of particles.
Wave Speed
Wave speed is the distance a wave pattern travels each second through a medium.
Doppler Effect
The change in the observed frequency (and wavelength) of a wave when the source and the observer are in relative motion.
Electromagnetic Spectrum
The complete continuum of all electromagnetic waves, organized in order of increasing frequency (or decreasing wavelength).
Loudness
Loudness is how strong or weak a sound seems to a listener.
Pitch
Pitch is how high or low a sound seems to a listener. It is mainly determined by the frequency of the sound wave.
Pressure Wave
A pressure wave is a longitudinal wave made of alternating regions of higher and lower pressure moving through a medium.
Refraction
The change in direction of a wave as it passes from one medium into another where it travels at a different speed.
Speed of Sound
The speed of sound is how fast a sound wave travels through a medium.
Standing Waves
Standing waves are wave patterns that stay in place, formed when two waves of the same frequency and amplitude travel in opposite directions and interfere.
Harmonics
Harmonics are the allowed standing-wave frequencies of a vibrating system. The first harmonic is the fundamental frequency, and higher harmonics are whole-number multiples of it.
Resonance
Resonance occurs when a system is driven at or near one of its natural frequencies, causing the amplitude of its oscillation to grow strongly.