This document provides information about energy and waves for a Year 9 science class. It begins with defining energy and naming common forms of energy like chemical, light, sound, and heat. It describes how energy allows objects and living things to function. It then discusses different types of waves like transverse and longitudinal waves, using light and sound waves as examples. It explains concepts such as amplitude, frequency, wavelength, pitch and loudness in relation to waves. Diagrams show the ear and how sound travels to be heard. Laws of reflection and uses of reflective surfaces are also covered. Success criteria and review questions are provided throughout.

1. Year 9
Ms Gibellini

2. SLOs

3. SLO
Define Energy
Name common forms of Energy

5. Energy
What is energy? Can we see it? What does it do?
Energy is the ability to do work
We cannot see energy but substances and objects
can have energy
All energy originally comes from the sun

6.  you have energy from your food and you use it to
grow and move and think
 a moving car has energy from petrol and they
use it to move
 radios from electricity and it uses it to make a
sound
 a glowing torch has energy from chemicals in a
battery and it uses it to make light

7. Types of Energy
/Stored /Active

9. Success Criteria
 Complete cut and paste of Energy Types
 Complete Sci pad page 74 Introduction to Energy
 List five things that energy can do?
Powers appliances, causes movement, creates light, heat
and sound
 Where does all energy come from?
SUN!
 Where do you get energy for your body from?
The food we eat – CHEMICAL ENERGY

10. SLO
 Describe energy Transformations
 Describe the Law of Conservation of Energy

11. Law of Conservation of Energy
Energy can neither be created nor
it is destroyed, however energy
can be converted from one form
of energy to any other form of
energy

12. Energy Changes
To describe an energy change for a light bulb we need to
do 3 steps:
Electricity Light + heat
1) Write down the starting
energy:
3) Write down what energy
types are given out:
2) Draw an arrow
What are the energy changes for the following…?
1) An electric fire
2) A rock being dropped from a cliff
3) An arrow being fired

13. Energy Chains
What are the energy changes for the
following…?
1) An electric fire
Electricity  Heat + light
1) A rock dropping from cliff
Gravitational  kinetic  sound + heat
1) An arrow being fired?
Elastic + gravitational kinetic  heat + sound

15. Energy Chains
Item Energy
In
Energy Out Energy Chain
Balloon Car Elastic Kinetic,
sound, heat
Dinosaur
Bow and
Arrow
Solar Light
Yo yo
Mouse trap
Slinky
Cap bomb

16. Item Energy In Energy Out Energy Chain
Windmill
Tuning fork
Ball
Teeth
Fan
Cars
Shaker

17. Item Energy In Energy Out Energy Chain
Windmill Kinetic kinetic + heat
Tuning fork Kinetic  kinetic + sound + heat
Ball Grav.  kinetic  sound + heat
Teeth Kinetic  elastic  sound + heat
+ kinetic
Fan Chemical  electrical kinetic +
heat + sound+ light
Cars Kinetic  elastic  kinetic +
sound + heat
Shaker Grav. + kinetic  sound + heat +
kinetic
Race Car Kinetic  Chemical  electrical
 sound + heat + light

18. Success Criteria
 Complete worksheets on energy chains
 Where does all energy originate from?
SUN
 Draw an energy chain for the human eye.
Light energy  electrical energy  chemical energy
 Describe the energy transformations taking place as a plane
takes off
Chemical electrical  kinetic + sound + heat 
gravitational + sound and heat
 Complete page 79 of Sci pad Energy Transformations and 77
energy changes in an engine

19. SLO
 Describe energy efficiency and calculate
efficiency of appliances

20. Energy Efficiency
We know that not all energy is used by appliances:
E.g. Light bulb
Electrical energy Light energy + heat energy
Light energy is useful energy, but in the case of a light
bulb heat energy is wasted energy.

21. Question:
Give an energy transformation for an electric stove
element.
Name the useful in an electric stove element.
Name the wasted energy in an electric stove element.

22. Walnut Energy
The scientific unit for energy is the joule (J).
1,000 J = 1kJ, kJ = kilojoules
If you heated 1 ml of water by 1’C, then the water would
gain 4.2 joules of heat energy.
We can use this to figure out how much energy 1 peanut
has in joules.

23. Walnut Energy
Aim: To find out how much energy is in a walnut
Method:

24. Results:
Energy Supplied by Peanut: B-A
Conclusion:
Which food had more energy in it?
walnut
Write an energy chain for these experiments.
Chemical  heat + light
Not all the energy is used to heat the water, what is it wasted as?
Light energy
Food Temp
After
A
Temp
Before
B
Change
in Temp
A -B
X 42
Energy in
Joules
Walnut
Marshmallow
Jelly bean

25. We use the following equation:
USEFUL ENERGY = ENERGY INPUT – WASTED ENERGY
From this we can calculate the ENERGY EFFICIENCY of an
appliance:
ENERGY EFFICIENCY = USEFUL ENERGY X 100
ENERGY INPUT
This gives us the energy efficiency as a percentage %.

26. e.g.
A radio is supplied with 3500J of electrical energy. 3000J is
released as sound energy; the rest is lost as heat energy.
What is the energy efficiency of the radio?
Step 1: Write out the information you have:
Energy Input = 3500J Useful Energy = 3000J Wasted E = 500J
Step 2: Write out the equation:
ENERGY EFFICIENCY = USEFUL ENERGY X 100
ENERGY INPUT

27. Step 3: Substitute in the numbers from Step 1:
ENERGY EFFICIENCY = 3000J X 100
3500J
ENERGY EFFICIENCY = 85.7 % round up to 86%

28. Questions:
1. A light bulb is supplied with 60J of electrical energy every second.
It transforms about 20J into light and the remaining 40J into heat.
What is the energy efficiency of the light bulb?
2. An electric motor transforms 1600J of the 2000J is supplied with
into useful work. The rest is dissipated as heat. How efficient is the
motor?
3. A car, when supplied with 250kJ of energy, converts 75kJ into
kinetic energy in the engine, the rest is dissipated as heat and sound
energy. What is the energy efficiency of the car’s engine?
4. An electric hairdryer is supplied with 4500J of electrical energy.
3000J of this energy is released as heat and kinetic energy to dry hair
with, the rest is released as sound and some light. What is the
energy efficiency of the hairdryer?

29. Success Criteria
 Complete pages 76 of Sci pad wasted energy
 For every 100 Joules of energy used by an electric light
bulb you get only 15 Joules of light energy.
a) What happened to the other 85 joules of energy?
Wasted as heat energy
b) What is the % efficiency of the light bulb?
Eff = useful/total energy x 100
= 15/100 x100
= 15 %

30. SLO
 Define a wave and describe two common
forms

31. Light and Sound waves
 Light travels in a straight line
 Sound is a vibration, longitudinal wave
 Light travels faster than sound,
 Sound =770 miles per hour
 650,500,000 miles per hour in air
 lightening and thunder
 Fireworks

32. Types of Waves
 Transverse Waves:
 Light, up and down or side
to side
 Longitudinal
 Sound waves
 vibrations are along the
same direction as the
direction of travel. (in and
out)

33. Vibrations
 How are sounds made?
Particles moving (vibrating)
 How does sound get from the source (say, the teacher's mouth)
to your ears?
By vibrating air particles moving from the source (mouth) to your
ears and banging into your ear drum
 How can we stop sounds?
Stop vibrating, stop particles from reaching your ears (ear muffs),
soft furnishings to absorb sounds (vibration) and stop them
reflecting back into the room
 Sound waves cannot be heard in space (vacuum, no particles)
because….?
Need particles to vibrate, no particles in space!

34. Success Criteria
 Complete scipad page 78
 How are sound waves made? What do they need?
When something vibrates, they need a medium (gas, air) to
move through. Need particles to vibrate.
 What type of wave are sound waves?
Longitudinal
 What type of wave are light waves ?
Transverse

35. SLO
Identify the amplitude, frequency and
wavelength of waves
Define and describe sound waves in
terms of pitch and loudness

36. Waves

37. Amplitude and Frequency

38. Pitch = Frequency
 Pitch is determined by the
wavelength
 The number of wavelengths passing
a point every second is called
Frequency, measure in Hertz
 Longer the wavelength – lower the
pitch
 Shorter the wavelength – higher
the pitch

39. Loudness = Amplitude
 The amplitude of a sound wave is related to the
energy (loudness and softness) that the wave carries,
measured in decibels.
 The stronger the vibration the greater the sound
energy

40. Reading waves
Wave Pitch (high/Low) Loudness
(loud/quiet)
A
B
C
D

41. Reading waves
Wave Pitch (high/Low) Loudness
(loud/quiet)
A Low loud
B Low Quiet
C High Loud
D High Quiet

42. Reading waves
 Wave A and B have the same frequency, but A is louder.
 Waves A and B have the same pitch.
 Waves C and D have the same frequency, but C is louder.
 Waves C and D have the same pitch.

43. 28/05/2015
Using an oscilloscope
1) Quiet sound, low frequency:
2) Quiet sound, high frequency:
3) Loud sound, low frequency:
4) Loud sound, high frequency:

44. Success Criteria
 Complete pages 78-81
 What affect does increasing the amplitude have on sounds?
Louder
 What effect does increasing the frequency have on sounds?
Wavelength is shorter, sound is higher pitched
 How does changing the pitch effect frequency and sounds?
Lower or higher depending on wavelength, greater the pitch
greater the frequency
 Draw a labelled diagram to show a wavelength and
amplitude on a sound wave.
 How do we calculate Hertz?
Number of wavelengths passing a point every second

45. SLO
Draw the basic structure of a human ear
What did the receiver say to the radio
wave? Ouch! That megahertz.

46. 28/05/2015
How sound travels…
As we know, sound waves are formed when something vibrates. But
how does the sound reach our ears?
1) An object makes
a sound by
vibrating
2) The vibrations pass through air
by making air molecules vibrate
3) These vibrations
are picked up by the
ear
Air molecules

47. 28/05/2015
How does the ear work?
1) Sound waves are
“funnelled” into the
ear by the pinna
4) These vibrations
are turned into
electrical signals in
the cochlea2) These
vibrations make
the ear drum
vibrate
3) These vibrations make the ear
bones vibrate
5) The electrical signals
are then sent to the brain

49. Ears and Hearing

50. The Ear
https://www.youtube.com/watch?v=HMXoHKwWmU8

51. Hearing
 Something vibrates and creates a sound wave.
 The sound wave travels to the ear and is collect by the outer ear.
 The sound wave then moves into the ear canal.
 When it reaches the end of the ear canal, the sound waves bump up against
the eardrum.
 The ear drum vibrates with these sound waves.
 The vibration moves tiny bones in the middle ear.
 These bones carry vibrations into the inner ear to a fluid-filled tube called
the cochlea.
 The fluid inside the cochlea vibrates a series of tiny hairs called cilia, which
are attached to auditory nerves.
 The movement of these cilia stimulates the nerve cells, and they send
signals to the brain via the auditory nerve.
 The brain processes these signals into the sounds we hear

53. Success Criteria
 Complete Scipad pages 78-82 on Waves and Sound
 Draw a flow diagram to show how the human ear
works (how sounds move from outer ear to brain, and
what kind of energy forms they change to)
 Draw a labelled diagram of the ear, what effect does
increase the pitch have on the ear drum? What about
increasing the amplitude?

54. Hearing Simplified
Sound vibrations enter
Pinna  ear canal  ear
drum  hammer  anvil 
stirrup  semi circular canal
 cochlea  Cilia  nerve
 brain

55. SLO
Describe some properties of light
and give some examples

56. Light
Make a list of all the things that we use light for
 help us see things,
 can burn us,
 creates rainbows,
 helps plants produce food – photosynthesis
 helps us take photos
 reflects - mirrors
 can be hot or cold

57. Properties of light
The light has three distinctive properties:
 moves in a straight line.
 It reflects when it reaches a reflecting surface.
 Changes direction as it passes from one medium to
another (is refracted).

59. Sources of Light
List as many sources of light as you can.
Light sources can be grouped:
Incandescent Sources:
 Light produced by heat.
 flame
 light bulb
 sparks
 bar heater
 stars
 lightning
Cold Light:
 glow worms, fire flies
 phosphorescence – TV monitors, fluorescence tubes
 fluorescence – clock faces, glow in the dark things
 luminescence

60. Reflected Light
The moon reflects the suns light, it does not emit it
is own light.
We see other objects that are not light sources,
because light rays from other sources bounce off
them in all directions. ( Light is reflected)

61. Success Criteria
 Complete scipad 83 - 84

62. SLO
Draw ray diagrams and use them to
explain shadows

63. BBC
 BBC bitesize
 Puppet clip

64. Shadows
 A region without light is called a shadow.
 The shape of the shadow may not be identical to the shape
of the object because the shadow’s shape depends on the
position of the light source and on where the shadow falls.
 The size and intensity of the shadow depends on the size of
the light source and the distance between the light source
and the object.

65. Success Criteria
 Make a shadow head of yourself, make it a big warped
so it looks funny by playing with the angles
 Complete page 85-86 of scipad
 http://www.youtube.com/watch?v=NZ5MJqB9myA

66. SLO
Observe reflection and use the Laws of
Reflection to explain observations
Measure and record angles
Identify and make predictions from
patterns in data

67. Reflection
 What is it about objects that let us see them?
 Why do we see the road, or a pen, or a best friend?
 If an object does not emit its own light (which accounts
for most objects in the world), it must reflect light in
order to be seen.

68. Reflection
 The angle of reflection always
equals the angle of incidence.
 The normal is an imaginary line at
right angles (90 degrees) to the
point where the incident ray hits
the mirror.

69. Drawing Ray Diagram Rules
 Ruler
 Pencil
 Straight lines, with arrows
 No sketching
 Lines on back of mirror
 Light box at correct angle
 Correct number of rays

71. Success Criteria
 Complete Page 87 of scipad
 Draw a diagram to show how a periscope works
(remember your eyes do not emit light so have the
arrows going the correct direction and light travels in
straight lines so use a ruler!)

72. SLO
Describe various uses of reflective surfaces
Observe the effect of convex and concave
mirrors on rays of light

73. Uses of Reflective Surfaces
 Where are mirrors used?
 Periscopes
 Cars
 Satellites
 Fibre optics
 photography
 How are they used? Video

74. Curved Mirrors
 Concave mirrors cause the light rays to converge
together:
 Convex mirrors cause light rays to diverge

75. Rays and Angles
Incidence Ray
Reflected Ray

77. Success Criteria
 Complete scipad page 89-91
 Complete the following ray diagrams, label the mirrors
as well.
 Video

78. SLO
Observe refraction and explain your
observations
Investigate refraction in lenses of various
shapes

79. Refraction
 Put the coin in a beaker, hold a ruler
vertically on a bench.
 Put your eye at the zero mark on the ruler
and get your partner to move the beaker
away until you can see to coin (over the lip
of the beaker).
 Slowly add water to the beaker, what
happens to your view of the coin?
 Move your eye down towards the bench
until you can see the edge of the coin again.
 How far down did you have to move?
 What has happened? Why?

81. Refraction
 The bending of light is called refraction.
 Light bends when it passes through substances of
different densities. (air to water, air to glass)
 The more dense a substance the more it bends

82. Refraction In Lenses

83. Lenses
 Lenses are curved pieces of
glass or plastic
 Convex lenses cause rays to
converge (come to a point)
 Concave lenses cause rays to
diverge (go away from each
other.

84. Success Criteria
 What is the difference between refraction and reflection,
draw a diagram to illustrate your answer.
 Reflection – light rays bounce off,
 Refraction the light rays are bent as they go from one
medium to another
 What do we call it when light bends as it passes between
mediums?
 The light rays entering an leaving a glass block should be?
parallel
 Complete pages 92-95 of Scipad

85. SLO
Investigate the appearance of
coloured objects

87. Dispersion of Colours
 Visible or White light is made up of 7 different colours
ROYGBIV
 Different colours have different wavelengths (distance
between two peaks)
 We can only see the visible part of the electromagnetic
spectrum(all of the different lengths of waves)

88. Dispersion of colour
 We can split white light into its different parts using a
prism, this is called Dispersion. (water can do this to
form a rainbow)
 Different colours have different wavelengths so travel at
different speed through glass or water, therefore they
refracted (bent) different amounts, and therefore
dispersed (spread out).

90. Seeing colour
 Why is a leaf green, milk white and a
tomato red?
 When white light hits an object most
wavelengths are absorbed, the one
colour that is reflected is the colour of
the object
 A green leaf reflects green light and
absorbs all other colours, hence it
appears green

91. Seeing colour
 Explain why milk is white
and a tomato is red.
 Milk reflects all colours, so
appears white
 Tomato absorbs all colours
except red, it reflects red to
your eye so looks red!

92. Mixing Colours
 Red, yellow and blue are called the primary colour
lights.
 We can use these three colours to make many different
colours.

93. Light Practicals
 White light is made up of a mixture of colours
(ROYGBIV). A coloured filter will let through some of
the colours and stop others.
 Which filters will let through?
 Red – red, magenta
 Green –Green, cyan
 Blue –blue, magenta, cyan
 Yellow –yellow
 Magenta (red and blue) –Red, blue
 Cyan (blue & green) – Blue, green

94.  Predict what colours will get though when:
 Light that passes through a primary red filter hits a primary
blue filter. - magenta
 Light that passes through a primary red filter hits a primary
green filter. black
 Light that passes through a primary green filter hits a
primary blue filter. cyan
 Now carry out experiments to test your predictions.

95. Success Criteria
 Complete scipad pages 100-102
 Why does white paper still appear white even though the white
light shining on it is made up of ROYGBIV?
Colours are all squashed together so appears white
 What is the name given to the part of the electromagnetic
spectrum that we can see?
visible
 When white light passes through a green filter what colour do we
see?
Green
 Why do we see a spectrum of different colours when white light is
shone through a prism and not just a white spot?
White light is made up of ROYGBIV and the prism bends them all by
a different amount so we see them
 What do we see when we shine red light onto blue paint?
Magenta
 Why do leaves look green?
Because white light is made up of ROYGBIV and leaves absorb
ROYBIV and reflect Green light to your eyes!

96. SLO
Describe the basic structure and
function of the human eye

99. Structure of the Eye

100. How our eyes work
 Light enters the eye through the cornea and pupil
 The light is focused onto the back of the eye (retina) by
the lens
 The retina is covered in light sensitive cells called light
receptors
 The receptors change the light energy into electrical
energy and a message is passed from the optical nerve to
the brain

101.  http://www.e-
learningforkids.org/Courses/Liquid_Animation/Body_
Parts/Vision/index.html
 https://www.youtube.com/watch?v=syaQgmxb5i0

102. How we See

103. Seeing Colour
 Cones see colour
 Humans have three different types of cones, red, blue
and green

107. Success Criteria
 Complete page 96-99 of scipad
 Describe the following terms, use diagrams to help:
colour blindness, short sighted, long sighted

108. Revision
 https://www.youtube.com/watch?v=CbkaL-vgiKI