1. Physics of Sound WAVES

2. Sound is a wave. It is a wave of energy that moves through matter; solids, liquids, gases.

3. A wave is a disturbance or variation that moves through a medium.

4. It is a special type of wave it is a compression wave

8. As with all waves, it has certain basic parts and characteristics.

9. Wavelength Wavelength is the distance from one crest to another of a wave. Since sound is a compression wave, the wavelength is the distance between maximum compressions.

10. Amplitude The amplitude of a sound wave is the same thing as its loudness. Since sound is a compression wave, its loudness or amplitude would correspond to how much the wave is compressed. It is sometimes called pressure amplitude.

11. Frequency The frequency of sound is the rate at which the waves pass a given point. It is also the rate at which a guitar string or a loud speaker vibrates. Frequency is also called the pitch of a sound. It is called the note in musical sounds.

12. Relationship The relationship between velocity, wavelength and frequency is: velocity = wavelength x frequency Since the velocity of sound is approximately the same for all wavelengths, frequency is often used to better describe the effects of the different wavelengths.

13. Pitch The pitch or note of a sound that we experience is determined by its wavelength or its frequency. The shorter the wavelength, the higher the frequency becomes, and the higher the pitch that we hear.

14. Characteristics of sound A sound wave has characteristics just like any other type of wave, including amplitude, velocity, wavelength and frequency.

15. Decibel A common measurement of loudness is the decibel (dB). It is really 1/10 of a bel, which was named after the inventor of the telephone, Alexander Graham Bell. It is a complex unit that varies as the ratio of the logarithms of loudness.

16. Decrease in loudness A sound wave will spread out after it leaves its source, decreasing its amplitude or loudness. The amplitude decreases as the square of the distance from the source. Also, if there is some absorption in the material, the loudness of the sound will decrease as it moves through the substance.

17. Speed or velocity of sound The speed or velocity of sound in air is approximately 344 meters/second, 1130 feet/sec. or 770 miles per hour at room temperature of 20C (70F). Speed is different depending on temperature of air, sound travels slower in colder air.

20. Doppler effect