1. Interactions
of waves

2. Ways Waves Interact Reflection Refraction Diffraction Interference
Constructive
Destructive
Standing Waves

3. Reflection the turning back of a wave when
it reaches the boundary of the
medium through which it is traveling

4. Law of Reflection the angle of incidence is equal
to the angle of reflection

5. perpendicular

6. Examples of reflection
Mirror
Echo
Ball against a wall

7. Reflection
When an object or wave hits a surface through which it cannot pass, it bounces back.

8. Refraction
the bending of a wave as it passes obliquely from one medium into another at a different speed
For refraction to occur, the wave
must change speed and must enter
the new medium at an oblique angle.

9. Refraction
When a wave moves from one medium into another medium, at an angle, it changes speed as it enters the second medium which causes it to bend.
The bending of waves due to a change in speed is called refraction.

10. Change in Medium Animation

11. The greater the change in speed, the more the wave bends.
Light goes air to water, slows
and bends toward normal.

12. Light goes water to air, speeds up and bends away from normal.

13. Rainbows Light passing through water causes light to refract. The
colors , being
different
wavelengths,
refract different amounts. It is always ROYGBIV.

14. Diffraction the spreading of a wave around a barrier or
through an opening

15. Diffraction
When a wave passes a barrier, or moves through a hole in a barrier, it bends and spreads out.

16. Diffraction
Sound being heard from around a corner and light being seen around a corner are examples of diffraction.
Diffraction depends on wavelength and the size of the hole or bend.
Matter cannot be in the same space at the same time but energy can!
No! For real?

17. Interference
Interference is the overlapping of two or more energy waves.
Cool!

18. What is wave interference?
Waves interfere in one of two ways: Constructive Interference and Destructive Interference.

19. Constructive interference
Constructive interference occurs whenever two waves combine to make a wave with a larger amplitude.

21. Constructive Interference
Let’s consider two waves moving towards each other, both having a positive upward amplitude.
What will happen when they meet?

22. Constructive Interference
They will ADD together to produce a greater amplitude.
This is known as CONSTRUCTIVE INTERFERENCE.

23. Destructive interference
Destructive interference when the amplitudes of two waves combine producing a smaller amplitude.

24. Destructive Interference
Now let’s 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?

25. Destructive Interference
This time when they add together they will produce a smaller amplitude.
This is know as DESTRUCTIVE INTERFERENCE.

26. Types of Interference Constructive results in a larger amplitude
Destructive
results in a smaller amplitude

27. Check Your Understanding
Which points will produce constructive interference and which will produce destructive interference?
Constructive
G, J, M, N
Destructive
H, I, K, L, O

28. A standing wave is the
result of two waves of the same
wavelength, frequency, and amplitude
traveling in opposite directions
through the same medium.