6 1. reeds 3. membranes 2. strings 4. air columns Sounds are produced by vibrating matter.1. reeds3. membranes2. strings4. air columnsSound is a mechanical wave (longitudinal).It will not travel through a vacuum.
7 Sounds possess thecharacteristicsand properties thatare common to allwaves.
8 Just like all longitudinal (compression) waves, sound waves possess a velocity, frequency, wavelength,phase, period, and amplitude.Sound waves also reflect, refract,diffract, and interfere.
9 The velocity of sound in air depends on the air temperature. The speed ofsound in dry air is m/s at 0 ºC.This speedincreaseswith temperature: about 0.6 m/sfor every 1 ºC increase in temperature.
10 Sound generally travels fastest in solids and slowest in gases, but there are some exceptions.Medium Velocity (m/s) Medium Velocity (m/s)Air Carbon dioxide 260Helium Hydrogen 1270Oxygen Water 1460Sea water Mercury 1450Glass Granite 5950Lead Pine wood 3320Copper Aluminium 5100
11 The human ear relatesamplitude toloudnessandfrequency topitch.
12 Doppler Effect A tone is not always heard at the same frequency at which it is emitted.When a train sounds its horn as it passes by, the pitch of the horn changes from high to low.Any time there is relative motion between the source of a sound and the receiver of it, there is a difference between the actual frequency and the observed frequency.
13 * Fact * Resonance - the inducing All objects have a natural frequency of vibration.Resonance - the inducingof vibrations of a naturalrate by a vibrating sourcehaving the same frequency“sympathetic vibrations”
14 Famous Bridge Collapses: Evidences of Resonance? Tacoma Narrows linkOthers link