2: Sound Last updated Jun 23, 2019 Save as PDF 1.7: Waves on Strings 2.1: Introduction Page ID17105 BoundlessBoundless ( \newcommand{\kernel}{\mathrm{null}\,}\) Topic hierarchy2.1: IntroductionSound is a longitudinal wave of pressure that travels through compressible medias, which can be solid, liquid, gaseous, or made of plasma.2.2: Sound Intensity and LevelSound Intensity is the power per unit area carried by a wave. Power is the rate that energy is transferred by a wave.2.3: Doppler Effect and Sonic BoomsThe Doppler effect is the apparent change in frequency of a wave when the observer and the source of the wave move relative to each other.2.4: Interactions with Sound WavesSuperposition occurs when two waves occupy the same point (the wave at this point is found by adding the two amplitudes of the waves).2.5: Further TopicsSpherical waves come from point source in a spherical pattern; plane waves are infinite parallel planes normal to the phase velocity vector.