1. Behavior of Waves

2. S8P4. Students will explore the wave nature of sound and electromagnetic radiation. a. Identify the characteristics of electromagnetic and mechanical waves. d. Describe how the behavior of waves is affected by medium (such as air, water, solids). f. Diagram the parts of the wave and explain how the parts are affected by changes in amplitude and pitch.

3. What is a wave?

4.  A disturbance that transfers energy through matter or space.  Waves carry energy NOT MATTER!

5. What is a medium?  The matter that the waves travel through.  Solid, liquid, gas  The medium does not travel with the wave.

6. What is a mechanical wave? A wave that has to have matter to travel. Ex. Sound

7. What is an electromagnetic wave?

8.  Waves that do not require a medium to travel.  They can travel the fastest through space.

9. What are two types of waves?  Compressional Wave &  Transverse Wave

10. What is a compressional (longitudinal) wave?

11.  Matter in the medium moves back and forth in the same direction that the wave travels.

12. What are the parts of a compressional wave?

13.  Compression – particles are crowded together (more dense region)  Rarefaction – particles are spread further apart (less dense region)

14. What is an example of a compressional wave? Sound travels by compressions and rarefactions. Sound travels by compressions and rarefactions.

15. What is a transverse wave?  A wave in which the motion of the medium is at right angles to the direction of the wave.

16. How do you label a transverse wave?

17. What are some wave parts? Crest – highest point Trough – Lowest point

18. What is the amplitude?  The maximum distance the molecules are displaced from their rest position. (Height of the wave.)

19. Amplitude...

20. What is the relationship between amplitude and energy?  The more energy the wave has the higher the amplitude (taller the wave).

21. What is wavelength?  The distance between one point on a wave to one point just like it.  Crest to Crest (Trough to Trough)  Compression to Compression (Rarefaction to Rarefaction)

22. Wavelength

23. What is frequency?

24.  The number of wavelengths that pass a fixed point each second. (Unit = Hertz (Hz).

25. How are frequency and energy related?  More energy, the higher frequency.  It takes more energy for a wave to vibrate quickly.

26. What is wave speed dependent upon?  A wave will move slower in a dense medium.  It is harder to get a dense medium to respond to the energy of the wave.

27. How do you calculate speed? Speed = frequency x wavelength m/s Hz m m/s Hz m V = f x

28. What would happen if waves encountered a different medium, reached another obstacle, or met another wave?  Wave Behaviors : Reflection, Refraction, Diffraction, Interference

29. What is reflection?  The bouncing back of waves after striking an object.

32. What is refraction?  The bending of waves due to a change in speed when traveling in different mediums.  Ex. Pencil in water

35. What is Diffraction?  Occurs when an object causes a wave to change and bend around it.

38. What is interference?  When two or more waves arrive at the same time.  Constructive and Destructive

39. Constructive interference...  When the crest of one wave meets the crest of another (trough to trough)

42. Destructive Interference...  When the crest of one wave meets the trough of another.