Slide 1

The Behavior of Waves Section 11.3 Slide 2 Reflection All types of waves can be reflected Light, sound, ocean, etc. Used by bats and dolphins Reflection- when a wave strikes an object and bounces off of it All types of waves can be reflected The angle of incidence of a wave is always equal to the angle of reflection. http://www.glenbrook.k12.il.us/gbssci/phys/Cl ass/refln/u13l1c.html http://www.glenbrook.k12.il.us/gbssci/phys/Cl ass/refln/u13l1c.html Slide 3 Reflection Normal- an imaginary line perpendicular to the reflective surface Angle of Incidence- the angle formed by the wave striking the surface and the normal Angle of Reflection- the angle formed by the reflected wave and the normal http://www.glenbrook.k12.il.us/gbssci/phys/m media/optics/lr.html http://www.glenbrook.k12.il.us/gbssci/phys/m media/optics/lr.html Slide 4 Reflection Slide 5 Refraction Why does an object partially in the water look broken or disconnected? Refraction- the bending of a wave caused by a change in the speed of the wave as it moves from one medium to another Greater change in speed = more bending of the wave When a wave moves into a medium that slows it down, the wave is bent toward normal When a wave moves into a medium that allows it to speed up, the wave is bent away from normal Slide 6 Refraction http://www.ps.missouri.edu/rickspage/refract/r efraction.html http://www.ps.missouri.edu/rickspage/refract/r efraction.html http://www.physicsclassroom.com/mmedia/w aves/ltm.html http://www.physicsclassroom.com/mmedia/w aves/ltm.html http://www.physicsclassroom.com/mmedia/op tics/bp.html http://www.physicsclassroom.com/mmedia/op tics/bp.html Slide 7 Refraction Slide 8 Diffraction Light can bend- refract, bounce back- reflect, and change direction or bend after they strike an object Diffraction- an object causes a wave to change direction and bend around it Refraction and diffraction both cause bending, but refraction occurs when waves move through something, while diffraction occurs when waves pass around something. Slide 9 Diffraction http://www.walter- fendt.de/ph14e/singleslit.htm http://www.walter- fendt.de/ph14e/singleslit.htm http://www.colorado.edu/physics/2000/schroe dinger/two-slit2.html http://www.colorado.edu/physics/2000/schroe dinger/two-slit2.html If the obstacle is smaller than the wavelength, the wave diffracts (bends) a lot If the obstacle is much larger than the wavelength, the waves do not diffract as much The large the obstacle is compared to the wavelength, the less the waves will diffract. Slide 10 Diffraction Slide 11 Interference http://www.acoustics.salford.ac.uk/feschools/ waves/diffract.htm http://www.acoustics.salford.ac.uk/feschools/ waves/diffract.htm Interference- the ability of two or more waves to overlap and combine to form a new wave Waves pass right through each other and continue to travel in their original directions A new wave exists only while the two original waves continue to overlap Constructive interference- waves add together Destructive interference- wave subtract from each other Slide 12 Interference- green- resulting wave Slide 13 Interference http://id.mind.net/~zona/mstm/physics/waves/interference/intrfrnc.html Slide 14 Standing Waves Standing waves- a wave pattern that stays in one place Forms when waves of equal wavelength and amplitude travel in opposite directions- continuously interfering with each other Nodes- places where the two waves always cancel each other http://id.mind.net/~zona/mstm/physics/waves/ standingWaves/standingWaves1/StandingWa ves1.html http://id.mind.net/~zona/mstm/physics/waves/ standingWaves/standingWaves1/StandingWa ves1.html http://www.walter- fendt.de/ph14e/stwaverefl.htm http://www.walter- fendt.de/ph14e/stwaverefl.htm Slide 15 Resonance Resonance- the ability of an object to vibrate by absorbing energy at its natural frequency http://www.pbs.org/wgbh/nova/bridge/meetsu sp.html#clips bridge resonance http://www.pbs.org/wgbh/nova/bridge/meetsu sp.html#clips Breaking a glass with sound- resonance: http://www.teachersdomain.org/resources/lsp s07/sci/phys/energy/glassbreak/index.html http://www.teachersdomain.org/resources/lsp s07/sci/phys/energy/glassbreak/index.html