Properties and Interactions of Waves Week 2 Notes: Ch. 1, Sect 2 & 3 PAGE 11 – 23

I. AMPLIITUDE 1. The __DISTANCE__ the medium rises depends on the __AMPLITUDE__ of the wave 2. __AMPLITUDE__ is the maximum distance that the __PARTICLES__ of the __MEDIUM__ carrying the wave __MOVE__ away from their __REST__ position

A. Amplitude of Transverse Waves 1. Moves __UP__ or __DOWN__ from the rest position 2. You can find the amplitude by __MEASURING_ the __CREST__ or __TROUGH__ of the wave to the __REST POSITION__ B. Amplitude of a Longitudinal Wave 1. How __COMPRESSED__ or __RAREFIED__ the medium becomes 2. __MORE__ compressions means more __AMPLITUDE__

II. WAVELENGTH 1. The __DISTANCE__ between 2 corresponding parts of a wave is its __WAVELENGTH__ 2. Transverse wave: __CREST__ to __CREST__ Longitudinal wave: __COMPRESSION__ to __COMPRESSION__

III. Frequency 1. __FREQUENCY__ is the number of __COMPLETE__ waves that pass a given point in a certain amount of __TIME__ 2. Frequency is measured in units called __HERTZ__ 3. Hertz is named after Heinrich __HERTZ__ who discovered __RADIO WAVES__

IV. SPEED 1. __LIGHT__ waves travels faster than __SOUND__ waves 2. __SPEED__ = __WAVELENGTH__ X __FREQUENCY__ 3. __FREQUENCY__ = __SPEED__ / __WAVELENGTH__ 4. __WAVELENGTH__ = __SPEED__ / __FREQUENCY__

I. REFLECTION 1. When an object or a wave hits a surface through which it __CANNOT__ pass, it __BOUNCES__ back is called __REFLECTION__ 2. The Law of __REFLECTION__ stated that the angle of __INCIDENCE__ = the angle of __REFLECTION__ Perfect Reflection: http://www.wimp.com/perfectreflection/ (27 Sec)

II. REFRACTION 1. When a wave enters a new __MEDIUM__ at an angle, one side of the __WAVE__ changes __SPEED__ before the other side, causing the wave to __BEND__, the bending of the wave due to change in speed is __REFRACTION__ 2. A __RAINBOW__ is created due to __REFRACTION__

III. DIFFRACTION 1. When a wave moves __AROUND__ a barrier or through an __OPENING__ in a barrier, it __BENDS__ and __SPREADS__ out is called __DIFFRACTION__ BrainPop: Refraction and Diffraction (3:06)

IV. INTERFERENCE 1. __INTERFERENCE__ is the interaction between __WAVES__ that meet. A. Constructive Interference The __INTERFERENCE__ that occurs when waves __COMBINE__ to make a wave with a larger __AMP__ is called __CONSTRUCTIVE INTERFERENCE__ B. Destructive Interference 1. The interference that occurs when __WAVES__ combine to make a wave with a __SMALLER__ amp is called __DESTRUCTIVE INTERFERENCE__

V. STANDING WAVES 1. A __STANDING WAVE__ is a wave that appears to __STAND__ in one place, even though it is really __2__ waves __INTERFERING__ as they pass through each other

A. Nodes and Antinodes 1. Points of a wave that __MEET__ the resting position are called __NODES__ 2. Points of a wave that are __MAXIUM__ distance from the resting position are called __ANTINODES__

B. Resonance 1. __RESONANCE__ is an increase in the amplitude of a __VIBRATION__ that occurs when external vibrations match an object’s __NATURAL__ frequency 2. __STANDING__ waves occur in an object when it __VIBRATES__ at its natural frequency http://www.youtube.com/watch?v=wvJAgrUBF4w (3:39)