A wave is any periodic disturbance in a material from an equilibrium state which travels from one region to another.
All waves transfer energy through matter or space.
Two major types of waves are mechanical and electromagnetic.
A medium is the matter through which a wave is transmitted. The medium does not move along with the wave - only the energy is transmitted.
All waves have amplitude, wavelength, and frequency.
Amplitude relates to wave energy (intensity/wave height - trough, crest)
Wavelength is the distance between the same point on two successive waves.
Frequency depends on wavelength and speed. It is the number of waves that pass a point per second. (Measured in hertz Hz)
Wave period = 1/frequency ( T = 1/f )
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Transverse waves: motion of the medium is at right angles to the direction of the wave.
Longitudinal waves: motion of the medium is parallel to the direction of the wave.
Wave speed = frequency x wavelength
Wave interactions: reflection, refraction, diffraction, interference (constructive or destructive) (see 24-3 for sound wave interactions)
Standing wave (resonant frequency)
Sound waves are longitudinal mechanical waves with "compressions" and "rarefactions."
Speed of sound (m/s)
Pitch relates to the frequency of a sound wave as perceived by humans.
Doppler Effect: the difference in frequency between a sound produced and that perceived by a listener who is moving relative to the source.
Electromagnetic waves are transverse waves: the direction of the wave is at right angles to both the electric and magnetic fields (p643).
EM spectrum - energy increases with frequency.
Photon: a tiny bundle of light energy
Light behaves like a wave and a particle
Reflection of light
Refraction of light