Loudness is perceived as the energy of sound waves, determined by amplitude and distance from the source. Intensity, or energy per second, is measured in decibels. Pitch depends on frequency, measured in hertz, and humans can hear between 20-20,000 Hz. The Doppler effect describes how the frequency of sound changes depending on the motion of the source relative to the observer. Music is a pleasing combination of sound waves, while noise is an unpleasant combination.
To know that sound can be reflected, refracted, diffracted, and produces interference effects.
Know that sound is a wave because it can be reflected and refracted as with particles, diffraction and interference only occur with waves
To know that sound can be reflected, refracted, diffracted, and produces interference effects.
Know that sound is a wave because it can be reflected and refracted as with particles, diffraction and interference only occur with waves
2. Loudness Loudness is your perception of the energy that sound waves have Two key factors 1. Amount of Energy Amplitude 2. Distance from the source of sound Intensity = Energy per second 43
6. Pitch Depends on the frequency of the wave High frequency = High pitch Measured in unit called hertz (Hz) 80 Hz means 80 waves each second 44
7. Pitch Human Hearing 20 Hz to 20,000 Hz Above 20,000 Hz can not hear – Ultrasound Below 20 Hz – Infrasound 45
8. The Doppler Effect The frequency of sound changes depending on where you are IF things are MOVING Described by Christian Doppler (1803-1853) The motion of the source adds to the motion of the waves 46
9. Sound Barrier Shock wave is formed by the piling up of sound waves People on the ground experience as sonic boom 46
10. Music What is the difference between music and noise? How the sound waves combine! Music is a pleasing combination of waves Noise is unpleasant combination of waves 48
11. Tones Fundamental Tone = Lowest natural frequency Overtone = Higher natural frequencies They are multiples of fundamental tone Instruments designed to resonate specific overtones 49
15. Acoustics The study of how sounds interact with the environment Reverberation – repeated echoes Curved hard surfaces to direct sound Soft surfaces to absorb sound 52
