1. Waves & Energy Transfer

2. Waves
Waves: The transfer of energy through matter or space caused by a disturbance.
There are two types of waves-
transverse waves & longitudinal waves.

3. Waves Types
Transverse wave: the direction of motion of the medium is perpendicular to the direction of motion of the wave

4. Waves Types
Longitudinal wave: the direction of motion of the medium is parallel to the direction of motion of the wave

5. Waves Characteristics
Medium- the material through which the wave travels
The medium can be air (sound), water (ocean), spring (lab), vacuum (light).

6. Waves Characteristics
Amplitude- the maximum displacement of the medium from equilibrium
Wavelength (l)- the shortest distance between points where a wave pattern repeats itself

7. Waves Characteristics
frequency- the number of complete waves that pass a point per second
period- the shortest time interval during which the motion repeats itself

8. Waves Characteristics
velocity of a wave = wavelength x frequency
v = l * f
The speed of mechanical waves does NOT depend on amplitude nor the frequency. It depends on the properties of the medium. (e.g. depth of water, temperature of the air, elasticity of material, etc.)

9. Waves Properties
There are four properties of waves that are true for both transversal and longitudinal waves.
Reflection
Refraction
Diffraction
Interference

10. Waves: Reflection at Boundaries
occurs when a wave reaches a boundary of a medium
most of the wave is transmitted if the media are similar
if the difference is great, most of the wave energy will be reflected
if the new medium is more dense, the reflected wave will be inverted

11. Waves: Reflection
Law of Reflection: the angle of incidence is equal to the angle of reflection.
These angles are measured from the normal (perpendicular).
Law of Reflection: the angle of incidence is equal to the angle of reflection.

12. Waves: Refraction
Refraction: the change in the direction of waves at the boundary between two different media.

13. Waves: Diffraction
Diffraction: the spreading out of waves around the edge of a barrier.

14. Waves: Interference
Constructive Interference: occurs when wave displacements are in the same direction
Node- a point of undisplaced medium.
Antinode- point of maximum displaced medium.

15. Waves: Interference
Destructive Interference: occurs when wave displacements are in opposite directions.

16. Waves: Interference
Unlike waves coming into contact with matter, when waves pass by each other, the wave energy is transmitted through each other without losing energy.

17. Waves: Interference

18. Waves: Interference