1. Properties of Waves
Chapter 11: Section 3

2. Learning Targets Explain how energy is transferred through a wave
Give examples of mechanical and non-mechanical waves
Describe the different types of waves

3. Introduction So why does this happen?
When a pebble is dropped into water, small waves travel away from the area where the pebble was dropped
If you examined the motion of a leaf floating near this disturbance, you would see that the leaf moves around but always returns its original position
So why does this happen?

4. Wave Motion
Ripple waves in a pond start with a disturbance at some point causing water on the surface to move
These waves travel outward in a circular pattern away from the original disturbance

5. Note that the medium does not actually travel with the waves
In this example, the water in the pond is the medium through which the wave travels
Air can also act as an effective medium
Note that the medium does not actually travel with the waves
After the wave has passed, the medium returns to its original position

6. Mechanical Waves Most waves require a medium in which to travel
These types of waves are known as mechanical waves
Electromagnetic waves, such as visible light, radio waves, microwaves, and X rays, do not require a medium and can travel through a vacuum

7. Wave Types
A wave that consists of a single traveling pulse is called a pulse wave
If you continue to generate pulses at one end of a rope a periodic wave forms.

8. Transverse Waves
A wave in which the particles of the medium move perpendicularly to the wave motion, is called a transverse wave
Example: Slinky, “the wave”, water waves

9. Longitudinal Waves
When particles of the medium vibrate parallel to the direction of wave motion, the wave is called a longitudinal wave
Example: Compressed and stretched regions that travel along a spring
Sound waves are an example of a longitudinal wave

11. Waves Transfer Energy
Waves transfer energy by the vibration of matter rather than the motion of matter
As the waves spread out, particles in the medium transfer their vibrations from one particle to the next
Thus waves transfer energy from one place to another while the medium remains in essentially the same place

12. Waves are often able to transport energy efficiently
The rate of energy transfer depends on the amplitude at which the particles of the medium are vibrating.
The greater the amplitude, the more energy a wave carries