2. P7 Waves

3. This lesson What is a wave? Longitudinal and transverse waves
Amplitude, wavelength, frequency and period of a wave
The relationship between frequency and period
The wave equation

4. What is a wave? YouTube - Water bubble in Space (zero gravity)

5. Waves
Waves can transfer energy and information without a net motion of the material through which they travel.
They involve vibrations (oscillations) of some sort.

6. Waves
Waves can transfer energy and information without a net motion of the material through which they travel.
They involve vibrations (oscillations) of some sort.
Can you do something very boring and traditional………
Can you copy this please?

7. Transverse waves
The oscillations are perpendicular to the direction of energy transfer.
peak
Direction of energy transfer
oscillation
trough

8. Transverse waves
Water ripples
Light
On a rope/slinky
Earthquake

9. Longitudinal waves
The oscillations are parallel to the direction of energy transfer.
compression
Direction of energy transfer
oscillation
rarefraction

10. Longitudianl waves
compression
rarefraction

11. Longitudinal waves
Sound
Slinky
Earthquake

12. Wave measurements

13. Amplitude - A
The maximum displacement from the mean (average) position.
amplitude

14. Frequency - f
The number of oscillations/waves in one second. Measured in Hertz.
50 Hz = 50 vibrations/waves in one second.

15. Wavelength - λ
The length of one complete wave.
wavelength

16. Wave speed - v The speed at which energy is transferred along the wave
330 m.s-1

17. v = fλ The Wave Equation v = speed (m/s) λ = wavelength (m)
f = frequency (Hz) v f λ x

18. Some example wave equation questions
A water wave has a frequency of 2Hz and a wavelength of 0.3m. How fast is it moving?
A water wave travels through a pond with a speed of 1m/s and a frequency of 5Hz. What is the wavelength of the waves?
The speed of sound is 330m/s (in air). When Dave hears this sound his ear vibrates 660 times a second. What was the wavelength of the sound?
Purple light has a wavelength of around 6x10-7m and a frequency of 5x1014Hz. What is the speed of purple light?
0.6m/s
0.2m
0.5m
3x108m/s

19. Wave equation questionsλ f x

20. Let’s try some questions!
Page 125 (all the questions) and page 136 questions 1 and 4.