WavesWave - rhythmic disturbance that carries energy through matter or space.ex: water, sound, rope, springs, electromagnetic wave pulse - single disturbance, or bump, that travels through a medium Medium DOES NOT move with wave, wave passes THROUGHA. Parts of a Wave

 

 

wavelength = crest

trough

WavesB. Types of waves1. transverse wave - a wave pulse that vibrates perpendicular to the direction of wave motionex: water, rope, earthquakes S-waves 

 

WavesB. Types of waves 2. longitudinal/compressional wave - a wave pulse that vibrates parallel to the direction of wave motion.ex. sound, usually fluids/gases, earthquakes P-waves

 

 

WavesC. Wave calculations  

1. frequency - (f) number of complete oscillations a wave completes each second  

frequency = 1 = cycles = 1 hertz = 1 Hz time second

 

2. period – (T) the shortest time it takes a point on a wave to return to its original point

- in one period, a wave moves one wavelength

 period = 1 = time = 1 = 1 second frequency 1 1 hertz

3. Speed of a wave = wavelength x frequency  v = f = meter x 1 second

 

Waves

 

WavesD. Wave Behavior1. Reflection – tendency of a wave to “bounce off” or turn back when it reaches the boundary of an objectLaw of ReflectionThe angle of incidence is equal to the angle of reflection

 

WavesD. Wave Behavior

2. Refraction – tendency of a wave to bend when going from one medium to another due to change in wave speed.

 

WavesD. Wave Behavior

2. Law of Refraction (Snell’s Law) – index of refraction (n) is equal to the speed of light in a vacuum divided by the speed of light in medium.

n = c  v

WavesD. Wave Behavior3. Diffraction- tendency of a wave to bend around an object or through an opening.http://www.ngsir.netfirms.com/applets/diffraction/2X/Diffraction.htm

 

Waves D. Wave Behavior

Principle of SuperpositionWaves can combine to form a new wave. Algebraic sum of displacements of individual waves. Constructive interferenceWhen waves displace in the same directionA larger pulse is created with an ANTINODE.

 Destructive interference When waves meet and the displacement = 0 A NODE is formed where displacement is zero.

Important in music - tuning, echo 

Waves D. Wave Behavior

Standing wave – when two waves of the same frequency, wavelength, and amplitude interfere, they form a new wave which appears to be “standing” still, or not moving.  

Waves D. Wave Behavior - Standing Waves on a String

Harmonic –a standing wave pattern created by varying the wave frequency of vibration on a string.Integral variations of the fundemental frequency. 

Waves D. Wave Behavior - Standing Waves on a String

Harmonic –a standing wave pattern created by varying the wave frequency of vibration on a string.Integral variations of the fundamental frequency.