1 / 11

What is a sound wave?

What is a sound wave?. Mechanical wave – longitudinal A vibration Particles of medium are disturbed Causes a wave. causes. Most common medium is air Can travel through solids and liquids. Sound Interactions. Reflection Echo - when a sound wave reflects off a surface.

mandel
Download Presentation

What is a sound wave?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. What is a sound wave? • Mechanical wave – longitudinal • A vibration • Particles of medium are disturbed • Causes a wave causes Most common medium is air Can travel through solids and liquids

  2. Sound Interactions • Reflection • Echo - when a sound wave reflects off a surface. • Harder and smoother the surface the stronger the reflection. • Diffraction • Through openings (doorways) • Around corners • Interference • Can be: • Destructive – sound will be fainter • Constructive – sound will be louder

  3. Speed of Sound (SOS) • 343 m/s – at room temperature through air • Depends on medium sound is traveling through • 3 characteristics of the medium affect SOS: • Elasticity • Density • Temperature

  4. Elasticity • The ability of a medium to bounce back after being disturbed. • More elastic medium – the particles bounce back faster – sound travels faster. • Less elastic medium – the particles bounce back slowly – sound travels slower. • From faster to slower: solids > liquids > gases

  5. Density • Sound travels more slowly in denser mediums • Due to particles not moving as quickly back to rest position in denser materials (too crowded).

  6. Temperature • Sound travels more slowly at lower temperatures than higher temperatures. • Because particles move slower in lower temperatures.

  7. SOS final thoughts • The faster the particles of the medium can return to rest position – the faster sound will move through medium. • More elastic – faster (bounce back quicker) • Less dense – faster (not as crowded) • Higher temp – faster (particles naturally move faster) • First person to break sound barrier (go faster than sound) – Chuck Yeager • Flew at higher altitude b/c lower temp = lower SOS

  8. Properties of sound • Loudness – depends on amount of energy used to create sound (amplitude of wave). • Pitch – depends on frequency of wave.

  9. Loudness • Depends on 2 things: • The amount of energy it takes to make the sound. • The distance from the source of the sound. • Decibel (dB) – unit for loudness of sound • Intensity – The amount of energy a sound wave carries over a certain amount time in a particular area.

  10. Pitch • How high or low the sound seems • High pitch – high frequency • Low pitch – low frequency • Ultrasound – sound waves with freq. above normal human hearing. (Usually above 20,000 Hz) • Infrasound – Below human range of hearing (usually under 20 Hz)

  11. The Doppler Effect • The change in frequency (pitch) as a source of sound MOVES in relation to the observer. • Pitch increases as source moves toward observer. • Pitch decreases as source moves away. • Think of a siren approaching then passing by. It sounds different. • Can happen with light waves also.

More Related