Sound waves - Waves

Notes:

In this lesson, we will learn:

• The nature of sound waves
• How to solve problems relating frequency, wavelength, velocity, pitch, and loudness.
• Physical properties of sound
• Doppler shift and applications

Notes:

• Sound is produce by vibration of molecules.
• As the result of collision of molecules, the pressure is transmitted away form the source.
• Amplitude of sound is the measure of the variation in pressure, in other words Loudness, the louder sound has higher amplitude and more energy.
• The amplitude is measured by a scale called Sound Level.
• Sound level is measured in decibels (dB).
• Pitch:the sensation of frequency, high pitch high frequency.

• Speed of sound wave changes upon change in temperature, the higher the temperature the higher the speed.
• Sound can travel through solids, liquids and gases. (Highest speed in solids)
• Sound can NOT travel through vacuum (No particles to move and collide).
• Sound waves are characterized as longitudinal waves.
• Echoes: Reflected sound waves.
• Doppler shift: due to motion of the sound source or the observer, the detected frequency changes. The frequency of the source does NOT change.