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 ___________

*Rate your understanding (/10) for reflection, refraction and diffraction (will update this at the end of the lesson

Key words: reflection, refraction, diffraction

A. Long radio waves can bend around obstacles such as hillsB. 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

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 refraction ii. 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,

sold object, e.g. a plate reflection C. The bottom of a swimming pool looks

nearer than it actually is refraction

/61/6 or 2/6 = RED3/6 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 Properties Examples

Reflection e.g. the law of reflection states that …

Refraction The change in _________ of ________ when they travel across a b_______

S_______ pool appearing s_______than it is

Diffraction • 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 Examples

Reflection The change in direction of a wave, such as a light or sound wave, away from a boundary the wave encounters

• e.g. the law of reflection states that the angle of incidence = the angle of reflection

• occurs when light changes direction as a result of "bouncing off" a surface like a mirror

• Mirrorse.g. mirror sign in an ambulance

Refraction The change in direction of waves when they travel across a boundary

• Occurs in all forms of waves (e.g. light, sound)

• When a light ray travels from air into glass, the angle of refraction is smaller than the angle of incidence

• Swimming pool appearing shallower than it is

• water waves • White light

Diffraction The spreading out of waves when they pass through a gap or round the edge of an obstacle

• The narrower a gap is, the greater the diffraction

• The wider a gap is, the greater the diffraction

• 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

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

What are the properties of reflection, refraction and diffraction?

*if extra speedy: attempt the exam questions

HWK: • Make a summary poster (at least one side in books) on

reflection, refraction and diffraction (due Tues 30th April)

*Update your understanding (/10) for reflection, refraction and diffraction

What are the properties of reflection, refraction and diffraction?

Plenary: in 3’sa. 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)