Thurs. Mar. 6 Do Now:

1. Thurs. Mar. 6 Do Now: • Circle the type of wave that needs a medium through which to travel: Mechanical or Electromagnetic • A wave has a wavelength of 8m and a frequency of 4 Hz. What is the wave’s speed? ________  • Look at the two waves below. Circle the one with the greatest wavelength.

2. Learning Goals: • Students will be able to – • Explain the 4 ways in which waves interact • Illustrate the 4 types of wave interactions and provide examples of each

3. Activity: • You are going to investigate the different ways that waves interact with one another. • Each person needs to fill out a chart based about the 4 types of interactions: • Refraction • Reflection • Diffraction • Absorption

4. Reflection • When waves strike an object and bounce off of it • Examples • Mirror • Echos

5. Refraction • A wave travels from one medium to another so it changes speed and bends • Examples • Things under water • Prisms bending white light into colors

6. Diffraction • Waves bend around a barrier • Examples • Waves bend around rocks in the ocean

7. Absorption • Waves can be absorbed as they pass through objects • Amplitude gets smaller as it passes through material • Example: • Sponge absorbing water waves • Sunglasses have dark light that absorbs light

8. Activity Continued: • Once your chart is filled in you need to find your group and receive your assigned interaction • Your group will make a poster about the interaction including • Definition • Illustration • Examples

9. Do Now: • What do you think happens when two waves bump into each other? • Do you think a wave can stand still?

10. Learning Goals: • Students will be able to – • Define constructive and destructive interference • Classify standing waves, interference and wave behaviors in examples

11. Label amplitude:

12. Label the Wave Behavior: A: ____________________ B: ____________________

13. Label the Wave Behavior: C: ____________________ D: ____________________

14. Wave Interference • Two or more waves overlap and combine to form a new wave

15. Examples of Interference: • http://id.mind.net/~zona/mstm/physics/waves/interference/waveInterference2/WaveInterference2.html

16. Constructive Interference • When does it happen? • When waves are on the same side and add together • Same side = in phase • Crest adds to another crest • What happens to the amplitude? • Becomes larger

17. Destructive Interference • When does it happen? • Waves on opposite sides add together • Opposite sides = out of phase • Crest and trough meet • What happens to the amplitude? • Becomes smaller

18. Interference Constructive Destructive

19. Example – Sound Interference: • The sound from two speakers meeting and amplifying the sound is an example of _______________________ interference. • The sound from two speakers meeting and canceling out is an example of _________________________ interference.

20. Example – Light Interference: • The light from two sources meeting and amplifying the light is an example of ___________________ interference. • The light from two sources meeting and canceling each other out is an example of __________________ interference.

21. Standing Waves: • Occurs when a wave is trapped in one spot between boundaries

22. Practice on Your Own: • Complete the practice portion of today’s packet with a partner

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