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Waves & Quantum Phenomena. 7A, 7B, 7C, 7D, & 7F. IAN. Waves on a Coiled Spring- CER Does the transverse wave’s speed depend upon its amplitude?. Claim Evidence Draw and label a transverse wave. Wave speed equation? Reasoning. Does sound require a medium? Does light?.
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Waves & Quantum Phenomena 7A, 7B, 7C, 7D, & 7F
IAN Waves on a Coiled Spring- CERDoes the transverse wave’s speed depend upon its amplitude? • Claim • Evidence • Draw and label a transverse wave. • Wave speed equation? • Reasoning
Does sound require a medium? Does light? • Imagine you are in a vacuum.
Words you are expected to know • A means of transferring energy from one source to a destination w/o the transfer of matter btwn the two points • propagation= displacement of the wave • oscillation- repeated fluctuation (back & forth) energy
Types of Waves Mechanical Electromagnetic Does not require a mediumfor propagation Ex. Light, radio waves, etc. • Requires a material medium for its propagation • medium: solid, liquid, gas • Ex: sound, water wave, etc.
Mechanical Waves (7A) Transverse Longitudinal (compression) Vibrations are parallel to propagation Contains compression & rarefaction Ex: sound, seismic waves • Vibrations are perpendicular to direction of the propagation • Contains crest & trough • Ex: surface waves, light
Wave Terminology (7B &7C) Transverse Longitudinal Compression- compressed area Rarefaction- spaced out area Wavelength (λ)- compression to successive compression • Crest- highest point • Trough- lowest point • Amplitude- max displacement of a wave particle from the point of rest • Wavelength (λ)- distance from crest to successive crest
Frequency & Period Frequency (f) Period (T) Time it takes to make a complete wave T=1/f Unit: second, s • # of complete cycles within a second • What is the frequency? • 20 cycles in 1 second • 40 cycles in 2 second • Both= 20 Hz • Unit: Hertz= 1/s or s-1 • Wave speed • v=f λ
Wave Properties (7D) • Reflection • Refraction • Diffraction • Interference • Constructive • Destructive
Reflection • Wave bounces off an object and changes direction • angle of incidence=angle of reflection • Angle of incidence- angle hitting surface • Angle of reflection- angle bounced back • Reflection takes the shape of the barrier
Refraction • Changes direction of wave as it goes from one medium to another as a result of speed • Change in densities of mediums • Waves get closer in shallow medium • Wave speed • v=f λ
Diffraction • Spreading of wave around obstacles • The smaller the opening the more the spread • The longer the wavelength (), the more the spread
Why are you able to eaves drop from another room? Sound Light Small wavelengths • Large wavelengths
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Interference Constructive (positive) Destructive (negative) superposition of waves decreases size of resultant wave or cancels wave out • Superposition of waves increases size resultant wave
Applied Science Labhttp://www.msnucleus.org/membership/html/k-6/as/physics/5/asp5_2a.html CONCLUSIONS: How did you detect the different type of wave motion?
Applied Science Labhttp://www.msnucleus.org/membership/html/k-6/as/physics/5/asp5_2a.html
Sound (7D) • Sound level (unit: Decibel) • Pitch (connect to λ) • Resonance & echo • Doppler Effect • Acoustics (connect to interference) • Shock wave
Sound • Resonance- the frequency of sound waves exactly matches the natural frequency of an object causing an increase in amplitude of oscillations • Pitch- description of how high or low the sound seems to a person • Loudness- how loud or soft a sound is perceived to be. • Measured in decibels
Applications of Sound Waves • Ultrasound - sound waves with frequencies above the normal human range of hearing. • Sounds in the range from 20-100kHz • Sonogram- three-dimensional representation of a sound signal, using coordinates of frequency, time, and intensity • Doppler Effect- is the apparent change in the frequency of a sound caused by the motion of either the listener or the source of the sound (ex. sirens) • A moving source of sound or a moving observer experiences an apparent shift of frequency called the Doppler Effect. • If the source is moving as fast or faster than the speed of sound, the sound waves pile up into a shock wave called a sonic boom. • A sonic boom sounds very much like the pressure wave from an explosion