1. Chapter 11 Waves

2. Wave – a disturbance that transfers energy through matter or space.
Medium – the material a wave passes through

3. The energy travels, NOT the medium!
A wave does NOT carry matter with it! It just moves the matter as it goes through it.

4. Mechanical Waves- Waves that can only pass through matter.
Examples: sound and seismic waves.

5. Electromagnetic Waves- Waves that can travel through empty space.
Examples: light, radiowaves, microwaves

6. Types of Waves
Transverse Waves: waves that move the medium at right angles to the direction of waves are traveling.

7. Types of Waves
Longitudinal (Compressional) Waves: the particles move parallel to the direction the wave is moving, “push-pull” waves.

8. Wave animations
Waves travel through the medium without actually moving the medium with it. Basically the medium stays put while the wave moves some distance

9. Parts of a Wave Transverse wave: Crest- the highest point of the wave
Trough- the lowest point of the wave

10. Parts of a Wave Longitudinal (compressional):
compression- where the medium is close together
rarefaction- where the medium is spread apart

11. Amplitude- how far the medium moves from rest position (where the wave isn’t moving).
in a transverse wave – the height away from the “rest” position.
Remember the highest point is the crest and the lowest point is the trough.

12. The greater the amplitude, the greater the energy of the wave.
Amplitude- how far the medium moves from rest position (where the wave isn’t moving).
in a longitudinal wave - it is measured by how close or far apart the particles are.
of how compressed or rarefied the medium becomes.
The greater the amplitude, the greater the energy of the wave.

13. Wavelength – the distance between two corresponding parts of a wave.

14. The higher the frequency the more energy in the wave
Frequency – the number of waves that go past a point in one second; unit of measure is hertz (Hz) .
The higher the frequency the more energy in the wave
10 waves going past in 1 second = 10 Hz
1,000 waves go past in 1 second = 1,000 Hz
1 million waves going past = 1 million Hz

15. Wave speed
The speed depends on the medium the wave is traveling through.
Sound travels fastest through solids and slowest in air.
We calculate this by:
Wave speed= frequency x wavelength
Rearrange for frequency and wavelength in your notes.
Units:
speed – meters/second (m/s)
frequency – Hz (1Hz = 1wavelength per second)
wavelength – meters (m)

16. Think about it… As wavelength increases, frequency _.
As wavelength decreases, frequency __ __.
decreases
increases