1. P6 – The Wave model of Radiation

2. What creates a Wave? MUST: recall that waves transfer energy
SHOULD: be able to describe the form of longitudinal and transverse waves and give examples
COULD: Be able to explain the form of a wave using key terms

3. Longitudinal Waves These are compression Waves
Energy compacts particles closer together and this is passed through the medium (the material)
The energy displaces the material in the direction of the wave
EG SOUND WAVES
Example - SOUND waves

4. Longitudinal Soundwave

5. Task
AP6.4

6. Transverse Waves “Side to Side” waves
The energy displaces the material at right angles to the direction of the wave
Water Waves and ALL electromagnetic radiation (including light) are Transverse Waves

7. Transverse Wave

8. Tasks
Activity AP6.3

9. What can Change about a Wave?
MUST: Know the terms Wavelength, Frequency and Amplitude
SHOULD: Be able to use the Wave Equation
COULD: Be able to explain changes in wave patterns using the wave equation

10. What types of Wave are there?
Name the two different types of wave Give examples of each type of them

11. Wave Terms

12. Wavelength

13. Wavelength
The length of whole wave Cycle

14. Wavelength The length of whole wave Cycle
EG Peak to Peak, Trough to Trough

15. Wavelength The length of whole wave Cycle
EG Peak to Peak, Trough to Trough
Measured in metres (m)

16. Frequency

17. Frequency
How often waves come along

18. Frequency How often waves come along
EG Number of total wave per second

19. Frequency How often waves come along Number of total waves per second
Measured in Hertz (Hz)

20. Amplitude

21. Amplitude
The size of a Wave

22. Amplitude The size of a Wave
The Maximum Displacement from the Baseline

23. Amplitude The size of a Wave
The Maximum Displacement from the Baseline
Measure from Base to Peak or Base to Trough

25. Simple Examination Question
(b) This graph shows a microwave
Which distance A, B, C or D is the Wavelength of the Microwave? _____ (1)
Which distance A, B, C or D is the Amplitude of the Microwave? _____ (1)

26. Activity AP6.6

27. The Wave Equation

28. The Wave Equation
wave speed = frequency x wavelength

29. The Wave Equation wave speed = frequency x wavelength
(metres per second) (hertz) (metre)

30. The Wave Equation wave speed = frequency x wavelength m/s Hz m
(metres per second) (hertz) (metre)
m/s Hz m

31. The Wave Equation wave speed = frequency x wavelength m/s Hz m
(metres per second) (hertz) (metre)
m/s Hz m
Also written as v = fλ

32. How do Sound Waves Change?

33. How do Sound Waves Change?
Low Frequency = Long Wavelength

34. How do Sound Waves Change?
Low Frequency = Long Wavelength
Low pitch Sounds

35. How do Sound Waves Change?
Low Frequency = Long Wavelength
Low pitch Sounds
High Frequency = Short Wavelength

36. How do Sound Waves Change?
Low Frequency = Long Wavelength
Low pitch Sounds
High Frequency = Short Wavelength
High pitch Sounds

38. Tasks Activity AP6.8 – 10 minutes Calculations using the Wave Equation
Check your answer to question 4b - Is there anything wrong with this answer?
Text Book – Pages 236, 237
Questions 1 – 6

39. What can happen to waves in a medium?
MUST: know the terms reflection, refraction, diffraction and interference
SHOULD: be able to explain these wave effects
COULD: use wave effects to explain common phenomena

40. Starter

41. Tasks Watch the demonstrations
Complete the worksheet (AP6.11) from your observations

42. Definitions

43. Definitions
Reflection – When waves bounce off something

45. Definitions Reflection – When waves bounce off something
Refraction – As waves change medium they may slow down or speed up – This can create a change in course/direction

47. Refraction

48. Definitions

49. Definitions
Diffraction – After waves pass through a gap or pass a barrier, they spread out.

53. Definitions
Diffraction – After waves pass through a gap or pass a barrier, they spread out.
Interference – When waves meet they can reinforce or deconstruct

56. Tasks
Pages 238, 239
Copy and label the Wave Diagrams of Reflection, Diffraction and Interference
Include an explanation of what is happening

57. Wave Effects MUST: recall the wave effects
SHOULD: be able to describe how waves can be refracted
COULD: be able to explain the refraction effect

58. What are the Wave Effects?

63. Reflection

64. Refraction

65. Interference

66. Diffraction

67. How does Refraction occur?

68. How does Refraction occur?
Refraction is caused when waves change medium ( The Material that they are travelling through)

69. How does Refraction occur?
Refraction is caused when waves change medium ( The Material that they are travelling through)
This is because the waves CHANGE SPEED as they change Medium

70. Speed up or Slow Down?

71. Speed up or Slow Down?
When Light moves from AIR to GLASS it slows down

72. Speed up or Slow Down?
When Light moves from AIR to GLASS it slows down When Light Moves from GLASS to AIR it speeds up

74. Tasks
Page 240 – Copy and Label diagrams of Light Rays - Reflection and Refraction
Activity AP6.17

75. Plenary
Activity Sheet AP6.18

76. Is light really a Wave? MUST: recall evidence for light being a wave
SHOULD: be able to measure the critical angle for light
COULD: be able to explain the wave effects of light

77. What are these Wave Effects?
A. B. C. D.

78. Sound Waves?
Is sound a wave? Give at least three reasons for your answer

79. Sound is a Wave

80. Sound is a Wave
Sound Waves can:

81. Sound is a Wave
Sound Waves can: Be Reflected (Echo)

82. Sound is a Wave
Sound Waves can: Be Reflected (Echo) Be Refracted – passing through materials of different density

83. Sound is a Wave
Sound Waves can: Be Reflected (Echo) Be Refracted – passing through materials of different density Be Diffracted – Spread out as they pass through a gap

84. Sound is a Wave
Sound Waves can: Be Reflected (Echo) Be Refracted – passing through materials of different density Be Diffracted – Spread out as they pass through a gap Undergo Interference

85. Is Light a Wave?

86. Task Activity AP6.19 Light on Trial
Answer the Questions on the Properties of Light – Could this be done by particles and / or by waves

87. The shadow of a razor blade using laser light

88. The shadow of a needle

89. There is a bright spot in the centre of this shadow made by a tiny ball bearing.
The shadow of a razor blade using laser light.

90. Diffraction of waves by a barrier

91. The light from a laser shone through a single narrow slit

92. White light through a narrow slit gives coloured fringes.

93. The pattern formed by light passing through two narrow slits

94. Interference of water waves

95. Reflection of Light
Carry out Practical Activity AP6.20 Find the Critical Angle of Glass

96. Critical Angle - Glass

97. Critical Angles
The Angle at which light is totally internally reflected within a substance For glass this is around 42 degrees

98. Total Internal Reflection

99. Diamond

100. Critical Angle - Diamond

102. Refractive index of Gemstones

103. Plenary
Can you TIR in water?

104. What is the Electromagnetic Spectrum?
MUST: recall the radiations that make up the electromagnetic spectrum
SHOULD: be able to describe how Frequency and Wavelength change through the Spectrum
COULD: be able to explain how the changes in Frequency and Wavelength relate to the Wave Equation

105. Starter What are the 7 colours of the Rainbow?
What is the Speed of Light in air?
What happens to the speed of light in Water?
What happens to the speed of light in glass?

106. Starter Slows down – to around 200,000 km/s
What are the 7 colours of the Rainbow?
Red, Orange, Yellow, Green Blue, Indigo, Violet
What is the Speed of Light in air?
300,000 km/s
What happens to the speed of light in Water?
Slows down – to around 230,000 km/s
What happens to the speed of light in glass?
Slows down – to around 200,000 km/s

107. What is Light? An electromagnetic wave
Contains a range of Frequencies and Wavelengths that make up the different colours of light (ROY G BIV)
When mixed together they are seen as white light

109. Making a Spectrum

111. Task
AP6.24
Match the diagrams that represent each form of radiation to the Electromagnetic Spectrum
Give examples of each of the uses (Page 245 in Text Book)
Page 244
Questions 1, 2, 3 and 4

112. Task Complete Activity Sheet AP6.23a
You WILL need a Scientific Calculator for the Calculations (GET ONE FOR THE EXAM)
If you can’t work out the answers using the Wave Equation, try to predict the values.

113. Plenary
Electromagnetic Spectrum

114. The Risky Side of the Rainbow?
MUST: recall which radiations are the most harmful
SHOULD: recall how these radiations can be used and detected
COULD: be able to explain why these radiations are more harmful

115. Starter
List all the different types of radiation in the Electromagnetic Spectrum
Start at Radio Waves and go in order of Increasing Frequency / Decreasing Wavelength
Give a use of each one of the radiation types

116. Which radiations are Risky?

117. Which radiations are Risky?
Ultraviolet (UV)

118. Which radiations are Risky?
Ultraviolet (UV)
X-Rays

119. Which radiations are Risky?
Ultraviolet (UV)
X-Rays
Gamma Rays

120. Why are these Radiations Harmful?

121. Why are these Radiations Harmful?
Shorter Wavelengths

122. Why are these Radiations Harmful?
Shorter Wavelengths
Higher Frequency

123. Why are these Radiations Harmful?
Shorter Wavelengths
Higher Frequency
More energy in each Photon

124. Why are these Radiations Harmful?
Shorter Wavelengths
Higher Frequency
More energy in each Photon
IONISING Radiation - Causes atoms to break apart

126. How can we protect Ourselves from Harmful Radiations?

127. How can we protect Ourselves from Harmful Radiations?
Avoid them

128. How can we protect Ourselves from Harmful Radiations?
Avoid them
Use Materials that Block or Absorb the radiations

129. Tasks
Page 247
Copy and Define Key Words – Ultraviolet, Ionising Radiation, X-Rays, Gamma Rays
Answer Questions 1, 2 and 3

130. Tasks Activity AP6.29 Uses of X – Rays Activity AP6.28
X – Ray film badge

131. How is Infrared radiation useful to us?
ALL MUST: Recall the effects of Infrared radiation
SHOULD: Be able to explain the uses of infrared radiation
 COULD: Be able to describe and explain the changing frequency and wavelength of IR as it relates to different temperatures

132. Starter
List the Seven colours of the spectrum in order from Lowest Frequency/longest wavelength to highest/shortest
On either end of the spectrum, add the invisible radiations found immediately beyond these
List a couple of uses of these invisible radiations

134. Infra Red

135. Infra Red
Beneath the Visible Spectrum, beyond red

136. Infra Red Beneath the Visible Spectrum, beyond red
All objects give off some infrared

137. Infra Red Beneath the Visible Spectrum, beyond red
All objects give off some infrared
Most solids absorb infrared, causing temperature to rise

138. Infra Red Beneath the Visible Spectrum, beyond red
All objects give off some infrared
Most solids absorb infrared, causing temperature to rise
Only Higher Frequency IR can pass through glass and clear Plastics. Other frequencies are absorbed or reflected – See Greenhouse Effect

139. Infrared Radiation

140. Plenary
Practice examination question

141. How are Microwaves useful?
MUST: recall microwave and radiowave are transmission and absorption
SHOULD: be able to describe factors that that affect absorption
COULD: be able to explain the importance of the use of different radiations

142. Starter
Question sheet – X Rays
Radio Waves?

143. Microwaves and Radiowaves

144. Microwaves and Radiowaves
Primary use is for Communication (TV, Satellite, Mobile phones, Radio, etc)

145. Microwaves and Radio Waves
Primary use is for Communication (TV, Satellite, Mobile phones, Radio, etc)
UHF/VHF Radio waves and some Microwaves pass through the Atmosphere with very little absorption

146. Microwaves and Radio Waves
Primary use is for Communication (TV, Satellite, Mobile phones, Radio, etc)
UHF/VHF Radio waves and some Microwaves pass through the Atmosphere with very little absorption
Medium and Long Wave radiowaves are reflected off the Atmosphere
Of these, Microwaves have the shortest wavelength, so are diffracted the least

147. What stops a Microwave?
Demo

148. Microwave signal passes through Microwave signal stopped
What Stops a Microwave?
Microwave signal passes through
Microwave signal stopped

149. What stops a Microwave? Microwaves transmit through:
The Air / Atmosphere
Dry, Non Metallic Solids
Microwaves are stopped by:
Metals
Water / Moisture

150. Satellite TV
What happens to Satellite TV in a Very Heavy Thunderstorm?
Why?

152. Tasks
Activity AP6.34
Sketch the “Atmospheric Window” Graph into your Book.
Note which radiations transmit strongly through our atmosphere and those that don’t
Answer Questions 1 – 5
Extension – Text Book – Page 251 – Questions 6, 7 and 8

155. Is there anybody out there?
If you want to find signs of Life on Other planets and in Other Galaxies, what types of Radiation would you look for or use to try and send messages with?
Why?

156. Telescopes

157. Keck Telescope

158. Keck Telescope

159. Arecibo Radio Telescope

160. Pulsar Telescope

161. Looking into Space
Video Clip

162. Plenary
Question Sheet

163. How does a Radio work? MUST: recall the terms FM, AM and RF
SHOULD: be able to describe the differences in AM and FM
COULD: Be able to explain the difference between AM and FM and how they are used

164. Starter
Microwaves or Microwaves?
Worksheet Questions

165. Beacon fires
Beacon fires have been used throughout history to communicate warnings (the Spanish Armada) and as celebrations (Queen Elizabeth’s Silver Jubilee).
Are beacon fires a digital signalling device or an analogue device?
What problems might there be in communicating with signal fires?

166. Smoke signals
Analogue or digital?
What problems might there be using smoke signals?

167. Semaphore
Analogue or digital?

168. International flag signal code used by shipping
Analogue or digital?

169. Morse code
This is not just a digital signalling system but a binary tool. There are just two symbols used: a dot and a dash.

170. Radio waves
Radio signals are broadcast by modulating a radio wave. Today many signals are broadcast using an analogue system, but more and more signals are broadcast in digital form.

171. Fax machines
These use a binary digital system to transmit information: everything is transmitted as a stream of 0s and 1s down telephone cables.

172. Mobile phones
A digital binary device again: this time, the signal is transmitted in the form of microwave radiation through the air.

173. How does a Radio work? Page 252
Draw a Flow Diagram to show the stages in the process from Sound at the Transmission end to Sound at the Listener’s Radio
Copy and Define Key Words – Carrier, Amplitude Modulation, Frequency Modulation, Noise
Text Book – Page 253 – Questions 1 - 3

174. How does a Radio Work?

175. How does a Radio Work?
A Radiowave (RF Wave) is created

176. How does a Radio Work? A Radiowave (RF Wave) is created
A Modulator Combines it with a SOUND wave

177. How does a Radio Work? A Radiowave (RF Wave) is created
A Modulator Combines it with a SOUND wave
The Sound wave creates a Pattern in the repeating RF Wave

178. How does a Radio Work? A Radiowave (RF Wave) is created
A Modulator Combines it with a SOUND wave
The Sound wave creates a Pattern in the repeating RF Wave
The Modulated RF carrier waves are Transmitted

179. Reciever

180. Reciever
The Modulated RF wave is Received

181. Reciever The Modulated RF wave is Received
It is Demodulated (the RF carrier is removed)

182. Reciever The Modulated RF wave is Received
It is Demodulated (the RF carrier is removed)
The Electrical signal is amplified and creates the sound wave from the speakers

183. AM or FM?
AM – Amplitude Modulation
FM – Frequency Modulation

186. AM Amplitude modulation.
The amplitude changes from large to small to large again to copy the changes in the sound wave being carried by the radio wave.
The frequency does not change.

187. FM Frequency modulation.
The frequency changes from high to low to high again to copy those same changes in the sound wave being carried by the radio wave.
The amplitude does not change

188. Tasks
Text Book – Page 253 – Questions 1 - 3

189. Plenary
Worksheet Questions
Adding information to waves

190. FM and Digital
MUST: recall the differences between AM, FM and Digital Radio signals
SHOULD: be able to explain advantages of FM and Digital Signals
COULD: be able to explain the differences between Analogue and Digital Signals

191. Starter
Worksheet questions – AM / FM
Radio Signals

192. FM vs AM

193. FM vs AM
Noise creates extra unwanted variations in amplitude

194. FM vs AM
Noise creates extra unwanted variations in amplitude FM picks up less electrical interference (noise) than AM signals

195. Analogue vs Digital
Powerpoint Demonstration

197. How is Analogue converted to Digital?
Page Section J

198. Analogue vs Digital

199. Analogue vs Digital
Analogue signals have continuous variation

200. Analogue vs Digital Analogue signals have continuous variation
Digital signals have only 2 variations – ‘On’ or ‘Off’

201. Analogue vs Digital Analogue signals have continuous variation
Digital signals have only 2 variations – ‘On’ or ‘Off’
These Digital signals are Binary Code – 1’s and 0’s

202. Advantages of Digital

203. Advantages of Digital
Digital can be used by microprocessors (computers)

204. Advantages of Digital
Digital can be used by microprocessors (computers) Digital can carry more information every second than analogue

205. Advantages of Digital
Digital can be used by microprocessors (computers) Digital can carry more information every second than analogue Digital can be delivered with no loss of quality. ‘Noise’ can be cleaned up.

206. Tasks
Draw a diagram to compare the differences in transmission and reception of Analogue and Digital Signals (page 255)
Complete Questions 1, 2 and 3 – Page 254