1. Bouncing, Bending, and Squeezing Waves Wave Phenomenon

2. Huygen’s Principle A wave front is made up of WAVELETS Each WAVELET is a POINT SOURCE of circular waves WAVE RAYS are lines PERPENDICULAR to wave fronts that show wave travel DIRECTION

3. Huygen’s Principle Barrier blocks part of a WAVE FRONT Remaining WAVELETS make a shorter WAVE WAVE RAYS are BENT around CORNERS

4. Diffraction Opening much larger than WAVELENGTH of the wave Large number of WAVELETS in slit – LITTLE diffraction Opening is the same order as WAVELENGTH of the wave Small number of WAVELETS in slit – LOTS OF diffraction

5. Incident rayReflected ray θiθi θrθr θ i = θ r Normal – a perpendicular to a surface Regular Reflection Law of Reflection

6. Diffuse Reflection Reflection from an irregular surface

7. Refraction As a wave enters a new medium it MAY change speed. If it there is a change an the wave arrives at an angle its path will be BENT Going into a SLOWER medium bends TOWARD the normal and wavelengths SHORTEN Going into a FASTER medium bends AWAY from the normal and wavelengths LENGTHEN Which is the faster medium? Medium 1 – the wavelengths are longer and the ray is bent toward the normal going into medium 2

8. Polarization Randomly polarized set of waves Vertically polarized waves Polarizer A polarizing filter blocks out all waves except those with particles moving in a certain direction. This only works for TRANSVERSE waves – LONGITUDINAL waves can NOT be polarized.