1. Date Lesson1: Light Lesson Outcomes How I did Targets Connector
How does light travel?
(level 4)
Lesson Outcomes
How I did
Targets
Task 1:
Group material into transparent, translucent and opaque and explain how light is scattered in each scenario Level 5
Task 2:
Explain how light can be scattered when it is passed through a translucent object Level 6
Task 3:
Explore what happens when light falls on different objects Level 7

2. BIG picture What skills will you be developing this lesson?
Numeracy
Team work
Independent enquiry
How is this lesson relevant to every day life?

3. Seeing a luminous object
A luminous object gives out light and can also be called a light source.
How does light from a light bulb and other light sources reach your eye?
Light travels in a straight line directly into your eye.

4. Seeing a non-luminous object
Objects that do not give out light are non-luminous.
How does your eye see non-luminous objects such as a book?
Light from the light source strikes the book and some of the light is reflected into your eye.

5. Task 1 (Level 5) Task 1: Keywords for Task 1:
Use the words on the right to answer the questions below in full sentences:
What do you call an object that allows light to travel through it, allows some light to travel through it and does not let light through at all?
What is a luminous object?
What is a non-luminous object? How do we see such objects? Use a diagram to explain
Keywords for Task 1:
light
reflect
bright
object
transparent
Translucent
Opaque

6. Task 1: Answers

7. How can I improve on task 1?
Task 1: Review
Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.
Lesson Outcomes
How I did
Targets
Task 1:
Level 5
Met?
Partly met?
Not met?
How can I improve on task 1?

8. New information task 2
Sometimes we want glass to let the light in but not let people see in. Bathroom windows use obscuring glass. The trick is to allow the light through but to mix up the information the glass carries. This can be done by scattering the light rays.
Scientists often use a model before starting experiments that use more expensive equipment. Here you will be using water and milk to model scattering by obscuring glass.

9. New information task 2

10. New information task 2 Put 250 ml of water into the beaker.
One pupil secretly draws a letter about 2 cm high on a piece of scrap paper.
That pupil then puts the letter behind the beaker against the glass so that it can be seen through the water, as shown in the diagram above.
The other two pupils make a note of what letter they think they can see through the water.
The three pupils compare letters. If they are all the same, add five drops of milk to the water, stir, and try with another letter. Keep the letters the same size and thickness as the first letter. Continue, keeping a note of how many drops of milk have been added.
Continue this process until the letters do not agree.
Repeat the experiment twice more starting with fresh water each time.
Repeat the experiment one more time, but stop adding milk just before it starts to get difficult to read the letter, now move the letter backwards away from the beaker, what do you notice?

11. Results
Number of drops of milk
All 3 agree on the letter?

12. Task 2 (Level 6) Task 2: Keywords for Task 2:
Many types of obscuring glass are not frosted, but have a wobbly surface. Describe how this does the same job. Would this sort of glass be suitable for a bathroom screen?
Describe the difference between the way that the milk scatters the light and the surface unevenness scatters the light.
Extension:
Draw a diagram to explain what is happening to the light at different points in the experiment
Keywords for Task 2:
Reflect
Light
Bounces
Transparent
translucent
Opaque
Solid
Liquid

13. Task 2: Answers
The surface unevenness makes the light leaving the glass change direction at the surface. This ‘confuses’ the light, and makes it impossible to make out details of objects viewed through the glass.
The uneven surface refracts the light in unpredictable directions to confuse the information it carries. The milk droplets act like tiny ball-shaped mirrors to change the direction of the light.

14. How can I improve on task 2?
Task 2: Review
Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.
Lesson Outcomes
How I did
Targets
Task 2:
Level 6
Met?
Partly met?
Not met?
How can I improve on task 2?

15. New Information for Task 3
Many materials cannot be categorised easily because they are partly transparent. A thin sheet of white paper, for example, lets some light through.

16. Task 3: (Level 7)
Task 3:
Group the objects in order of how much light they will allow to pass through (transmit)
Test your ideas using the light meter
Where you wrong at any point?
Task 3: Extension
Define translucent, transparent and opaque using details from you light meter readings
Keywords for Task 3:
Transparent
translucent
Opaque
light
primary data
light meter
anomalies

17. Task 3: Answers

18. How can I improve on task 3?
Task 3: Review
Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.
Lesson Outcomes
How I did
Targets
Task 3:
Level 7
Met?
Partly met?
Not met?
How can I improve on task 3?

19. Review Match each word to a definition. 1 transparent 2 opaque
3 translucent
4 absorbs
5 emits
6 reflects
A light passes through but it is scattered so you cannot see clear images through it
B light can pass through
C gives out light
D light bounces off
E blocks light, creates a shadow
F ‘soaks up’ light
B light can pass through
E blocks light, creates a shadow
A light passes through but it is scattered so you cannot see clear images through it
F ‘soaks up’ light
C gives out light
D light bounces off