1. February 20 1.Notes on Reflection, Refraction, and Diffraction 2. After the notes, you will have the rest of class to work on the project

2. Behavior of Waves All waves can be reflected. = the “bouncing back” of a wave

3. The Law of Reflection Angle of Incidence = Angle of Reflection

4. Refraction = the change of wave direction at the boundary between 2 media The amount of bending, or angle of refraction, of the wave depends on how much the material changes the wave’s speed

5. Diffraction = the bending of a wave around a barrier or a small opening. Water diffractionSound wave

6. Factors That Affect Diffraction When the wavelength is long compared with the obstruction, the wave diffracts more. Long waves are better at filling in shadows. Foghorns emit low-frequency (long-wavelength) sound waves—to fill in “blind spots.” AM radio waves are very long compared with the size of most objects in their path. They diffract around buildings and reach more places than shorter wavelengths. Diffraction

7. The extent to which the water waves bend depends on the size of the opening.

8. Diffraction and Dolphins The echoes of long-wavelength sound give the dolphin an overall image of objects in its surroundings. To examine more detail, the dolphin emits sounds of shorter wavelengths.

9. Interference When two or more waves exist in the same medium, each wave moves as though the other were absent When they meet, they interfere with one another and make a new wave Constructive Interference – 2 waves combine to form a new wave with a large r amplitude. Destructive Interference – 2 waves combine to produce a wave with a smaller amplitude.

10. Blueprint (40 points) Blueprint is accurate to final product, including materials and dimensions (10 points) Blueprint is organized and legible (10 points) Blueprint is drawn to scale, with measurements stated for each part and scale indicated (10 points) Blueprint includes list of materials used (5 points) Blueprint lists the intended notes and their frequencies (5 points)

11. Summative Report The following two items should be addressed for your summative report. They should be typed or neatly hand-written, and submitted with your project and blueprint on the due date. Be sure to explain how increasing or decreasing the variable affects the pitch and whether this variable is directly or inversely proportional to the frequency of the note played. (4 points per variable) Temperature Material density Length of pipe

12. Summative Report Explain in terms of your project how you demonstrated the four basic wave properties (2 points per property): Amplitude Frequency Wavelength Wave velocity