1. Wave Interactions

2. Two objects cannot occupy the same space at the same time.
However, mechanical waves are not matter, but rather the displacement of matter.
This means two waves can occupy the same space at the same time.

3. There are 4 types of wave interactions:
Reflection
Refraction
Diffraction
Interference

4. Reflection
Reflection: the bouncing back of a wave when it hits a surface.
* Note: when waves hits a substance some of it is transmitted and some of it is reflected.
Transmitted means to pass through
This is why we can see objects and hear echoes.

5. Reflection At a free boundary, waves are reflected but not inverted.
At a fixed boundary, waves are reflected and inverted.
Wave reflects off Wave reflects off
a free boundary a fixed boundary

6. Refraction
Refraction: the bending of waves as they pass through different mediums that cause the speed of the wave to change.

8. Diffraction
Diffraction: change of direction of a wave when it hits an obstacle or edge.
Sound diffracts well around corners
Light does not diffract as much because the wavelengths are shorter

10. Interference Interference: when 2 or more waves combine
There are 4 types of interference:
Constructive interference
Destructive interference
Standing waves
Resonance

11. Constructive Superposition: the combination of two overlapping waves.
When the crests and troughs of different waves match there is constructive interference. They combine to make a wave with larger amplitude

12. Destructive
Destructive interference: when the crest of one wave meets the trough of another
The results are a smaller amplitude or no amplitude

13. Standing Waves
Standing Wave: the result of a combination of constructive and destructive interference

14. Standing waves look like they are standing still, but are not.
Standing waves have nodes and antinodes.

15. The points at which the two waves cancel each other are called nodes.
Where the string vibrates with the largest amplitude it is called antinode.

16. Resonance
Resonance : when 2 objects naturally vibrate at the same frequency.
The sound produced by one object causes the other to vibrate.
Body of a guitar resonates when the strings are strummed