What are the properties of reflection, refraction and diffraction?
Starter: copy out and complete the gaps
i.
The change of the direction of a light ray when it enters a glass
block from air is an example of _________
ii. The spreading of waves when they pass through a gap is an
example of ___________
iii. The image of an object seen in a mirror is formed because the
mirror causes light from the object to undergo ___________
Key words: reflection, refraction, diffraction
A. Long radio waves can bend around obstacles such as hills
B. Your remote control will still work if you point it away from the TV
towards a flat, sold object, e.g. a plate
C. The bottom of a swimming pool looks nearer than it actually is
*Rate your understanding (/10) for reflection, refraction and
diffraction (will update this at the end of the lesson
What are the properties of reflection, refraction and diffraction?
Starter: copy out and complete the gaps
i.
ii.
The change of the direction of a light ray when it enters a glass
block from air is an example of refraction
The spreading of waves when they pass through a gap is an
example of diffraction
iii. The image of an object seen in a mirror is formed because the
mirror causes light from the object to undergo reflection
A. Long radio waves can bend around
obstacles such as hills diffraction
B. Your remote control will still work if you
point it away from the TV towards a flat,
C.
sold object, e.g. a plate reflection
The bottom of a swimming pool looks
nearer than it actually is refraction
/6
1/6 or 2/6 = RED
3/6 or 4/6 = YELLOW
5/6 or 6/6 = GREEN
What are the properties of reflection, refraction and diffraction?
Task 1: Copy and fill out the table below (12m)
Definition
Reflection
Refraction
Diffraction
Properties
Examples
e.g. the law of reflection states
that …
The change in
_________ of
________ when
they travel across a
b_______
S_______ pool
appearing
s_______than
it is
• The n_______ a gap is, the
g_________ the diffraction
• The w_______ a gap is, the
_________ the diffraction
*if extra speedy: we do not normally see diffraction
of light in everyday life. Suggest a reason for this
What are the properties of reflection, refraction and diffraction?
Definition
Properties
Reflection
The change in
• e.g. the law of reflection states
direction of a
that the angle of incidence =
wave, such as a
the angle of reflection
light or sound
• occurs when light changes
wave, away from a
direction as a result of
boundary the wave
"bouncing off" a surface like a
encounters
mirror
Refraction
The change in
direction of waves
when they travel
across a boundary
Examples
• Mirrors
e.g. mirror sign in an
ambulance
• Occurs in all forms of waves
• Swimming pool
(e.g. light, sound)
appearing
• When a light ray travels from air
shallower than it
into glass, the angle of
is
refraction is smaller than the
• water waves
angle of incidence
• White light
Diffraction The spreading out • The narrower a gap is, the
of waves when
greater the diffraction
they pass through • The wider a gap is, the greater
a gap or round the
the diffraction
edge of an obstacle
• Diffraction of light
(e.g. telescope)
• Diffraction of
ultrasonic waves
(ultrasound)
• TV/radio reception
Review check 1: A, B or C?
Q1. What is shown in the diagram?
A. Reflection
B. Refraction
C. Diffraction
Q2. What is shown in the diagram?
A. Reflection
B. Refraction
C. Diffraction
Q3. What is shown in the diagram?
A. Reflection
B. Refraction
C. Diffraction
Review check 1: A, B or C?
Q1. What is shown in the diagram?
A. Reflection
B. Refraction
C. Diffraction
Q2. What is shown in the diagram?
A. Reflection
B. Refraction
C. Diffraction
Q3. What is shown in the diagram?
A. Reflection
B. Refraction
C. Diffraction
What are the properties of reflection, refraction and diffraction?
Task 2 (12m): On A4 paper, either
• Draw a comic strip for reflection, refraction and diffraction
• Draw an example for each one and label it
*if extra speedy: attempt the exam questions
What are the properties of reflection, refraction and diffraction?
Plenary: in 3’s
a. Make a learning resource (e.g. fill in the gap
exercise/label a diagram/multiple choice quiz) in pairs
to distribute to another group (8m) (include a mark
scheme)
b. You are then going to swap with another pair and
complete the task (6m)
*Update your understanding (/10) for reflection, refraction and
diffraction
HWK:
• Make a summary poster (at least one side in books) on
reflection, refraction and diffraction (due Tues 30th April)