1. NEW MODULE:
WAVES

2. By the end of the lesson you should be able to explain/know:
The difference between longitudinal and transverse waves
How to describe fully a wave
What amplitude, frequency, wave speed and wavelength mean.
They need to copy down these lesson objectives
At the end of the lesson, there is another slide which has the same thing on but is phrased in terms of lesson outcomes – so they can compare and think about whether they have understood.

3. Medium A medium is a substance or material that carries the wave.
The wave medium is not the wave and it doesn't make the wave; it merely carries or transports the wave from its source to other locations. 

4. Medium cont…
In the case of our slinky wave, the medium through that the wave travels is the slinky coils. In the case of a water wave in the ocean, the medium through which the wave travels is the ocean water. In the case of a sound wave moving from the church choir to the pews, the medium through which the sound wave travels is the air in the room. And in the case of the stadium wave, the medium through which the stadium wave travels is the fans that are in the stadium.

5. What are waves? transverse longitudinal Waves transfer energy
They can be transverse or longitudinal:
transverse
longitudinal
The motion of the wave is at a right angle to the direction of the wave
The motion of the wave is in the same direction as the wave
e.g. sound waves
e.g. light waves

6. What are waves?
They always do 3 things:
reflect
refract
diffract

7. Longitudinal Waves

8. Make a longitudinal wave using a spring between two people like this :
LONGITUDINAL WAVES
Make a longitudinal wave using a spring between two people like this :
Label compression and rarefaction – stretching and squashing of the wave – higher and lower frequency
What type of energy is the wave transferring?
In which direction is the energy moving?
In which direction is each part of the spring moving? [put a marker on the spring to help you see]
kinetic

9. A compression is a region in a longitudinal wave where the particles are closest together.
A rarefaction is a region in a longitudinal wave where the particles are furthest apart.

10. When you speak to someone, the air vibrates as a longitudinal wave :
LONGITUDINAL WAVES
You should have noticed that each part of the wave moves in the same direction as the direction the energy is moving in:
particle movement
energy movement
When you speak to someone, the air vibrates as a longitudinal wave :

11. Transverse Waves

12. TRANSVERSE WAVES kinetic What type of energy is the wave transferring?
In which direction is the energy moving?
In which direction is each part of the rope moving? [put a marker on the rope to help you see]
kinetic

13. Transverse Waves
Each part of the wave moves at right angles [90º] to the direction the energy is moving in:
Particle Movement
Energy Movement

14. Measuring Waves What sort of waves are these?
transverse or longitudinal?
a wave in the sea?
a wave in some string?
A sound wave?
A wave in a slinky spring?
A light wave?

15. Describing Waves

16. Drawing a wave

17. Amplitude Amplitude: is the maximum disturbance caused
by a wave (the height of a peak).
This is usually measured in metres.
Or: The height of a wave from its middle to its peak

18. Wavelength Wavelength: the distance between any two peaks.
This is usually measured in metres.
Or The distance from one point on a wave to the same point on the next wave

19. Frequency

20. Frequency
Frequency refers to how many waves are made per time interval, measured in Hertz (Hz)
This is usually described as how many waves are made per second, or as cycles per second.

21. High or Low Frequency?

22. Animation to demonstrate wavelength, amplitude and frequency

23. Wave Speed

24. speed = frequency x wavelength
Speed of waves
The speed of a wave is:
speed = frequency x wavelength
Speed is measured in metres per second (m/s)
Frequency is measured in _____
Wavelength is measured in ______
If a wave has a wavelength of 2 metres and a frequency of 5 Hz, what is its speed? Hz m

25.  Energy and Waves : A Question
The photograph shows waves travelling across the surface of a pond. 1m 
1) Is this an example of a transverse or longitudinal wave?
transverse