1. Integrated Science Unit 4, Chapter 12

2. 12.1 Two Types of Waves:A transverse wave has its oscillations perpendicular to the direction the wave moves.A longitudinal wave has its oscillations in the same direction as the wave moves. 3. Longitudinal WaveThe wave we see here is a longitudinal wave.The medium particles vibrate parallel to the motion of the pulse.This is the same type of wave that we use to transfer sound. show tuning fork demo4 4. Transverse WavesThe difference between the two types: 5 5. 12.1 Frequency, Amplitude andWavelength 6. 12.2 Graphs of Harmonic MotionKey Question:How do waves move and interact with things? 7. *Wave Shapes *PlaneWaves- a wave that has crests all in a straight line. 8. *Wave Shapes *CircularWaves- a wave that has circular wave fronts that move outward from the center. 9. Plane Waves 10. Circular Waves 11. *What happens when a wave hits anobstacle? *Reflection *Refraction *Diffraction *Absorption 12. REFLECTION 13. REFRACTION 14. DIFFRACTION 15. ABSORPTION 16. Wave InteractionAll we have left to discover is how waves interact with each other.*When two waves meet while traveling along the same medium it is called INTERFERENCE. 21 17. Constructive InterferenceLets consider two waves moving towards each other, both having a positive upward amplitude.What will happen when they meet? 22 18. *Constructive Interference*They will ADD together to produce a greater amplitude.This is known as CONSTRUCTIVE INTERFERENCE.23 19. Destructive InterferenceNow lets consider the opposite, two waves moving towards each other, one having a positive (upward) and one a negative (downward) amplitude.What will happen when they meet?24 20. *Destructive Interference*This time when they add together they will produce a smaller amplitude.This is know as DESTRUCTIVE INTERFERENCE.25 21. Wave Interference26 22. Check Your Understanding Which points will produce constructive interference andwhich will produce destructive interference? Constructive G, J, M, N Destructive H, I, K, L, O27 23. Your Turn:Create a graphic organizer using the following terms:1.Reflection2.Refraction3.Diffraction4.AbsorptionExplain what the term means. (use your own words)Draw a picture to represent what happens.List Examples