1. Section 1: The Nature of Waves
The Energy of Waves
Section 1: The Nature of Waves

2. Anticipation Guide: True or False
Light waves are mechanical waves because they must travel in a medium
In space, no one can hear an explosion
Water waves are a combination of longitudinal and transverse waves

3. What is a wave?
Definition: A wave is any disturbance that transmits energy through matter or space.

4. Waves carry energy, not matter
Waves use energy to do work on everything in its path. The waves do work on the water to make it move up and down as well as work on the leaf so it bobs up and down with the water.

5. Energy transfer through a medium
a wave can be described as a disturbance that travels through a medium, transporting energy from one location to another location.
The medium is simply the material through which the disturbance is moving; it can be thought of as a series of interacting particles.

6. Mechanical waves require a medium
Sound waves require a medium
Ocean waves require a medium
Waves on a string instrument require a medium
A mechanical wave is a wave which is not capable of transmitting its energy through a vacuum. In other words, it requires a medium

7. An example of a mechanical wave

8. Energy transfer without a medium
Electromagnetic waves are waves that do not require a medium to transmit energy
Examples of these are microwaves, TV, x-rays, and radio signals
While these types of waves can travel through a medium, they travel faster through empty space

9. Example of an electromagnetic wave
Waves in the electromagnetic spectrum vary in size from very long radio waves the
size of buildings, to very short gamma-rays smaller than the size of the
nucleus of an atom.

10. Types of Waves
Waves can be classified based on the direction that the particles of the medium vibrate compared to the direction in which the waves travel.
The two main types of these waves are transverse and longitudinal. If found in combination is called a surface wave.

11. Types of Waves: Transverse
Transverse waves have particles that vibrate in an up and down motion moving the waves across in a perpendicular manner to which the wave is traveling
Remember that perpendicular means to be at right angles
A rope is an example of a transverse wave.

12. Types of Waves: Transverse

13. Types of Waves: Transverse
Demonstration

14. Types of Waves: Longitudinal
A longitudinal wave has particles that vibrate back and forth along the same path that the wave travels.
A spring (or slinky) is an example of a longitudinal wave

15. Types of Waves: Longitudinal
Compression is when the spring is (particles are) tightly pushed together
Refraction is when the coils (particles) are spread farther apart.
A sound wave is an example.

16. Types of Waves: Longitudinal
Demonstration

17. Types of Waves: Combination
When waves occur at or near the boundary between two media (air and water for example) transverse wave and a longitudinal wave can combine to form a surface wave.
Surface waves look like transverse waves but the particles in the medium move in circles rather than up and down.

18. Types of Waves: Combination
Particles move forward at the crest and backward in the trough.

19. Anticipation Guide: True or False
electromagnetic
Light waves are mechanical waves because they must travel in a medium
In space, no one can hear an explosion
Water waves are a combination of longitudinal and transverse waves X
False
True
Sound waves require a medium
True
Also called surface waves.