1-4 Shadow (1.2)

• Natuurkunde
• Middelbare school
• havo
• Leerjaar 2

Shadow (p. 22)

Bluetooth 

- On

Stationary

- Books

- Pen and pencil

- iPad

Report

- NO

Lessonup

- Yes

Bags in

the cuboard

Phones in the phone holder

Lesson goals:

• Explain what light rays, partial shadow and full shadow is.  
  
• Name the types of light beams and explain their uses:

      Divergent light beams 

      parallel light beams. 

• Explain what a point source is. 
  

Light rays

• Light rays move in straight 

       lines. 

• Light rays only become vissible when they reflect off other objects, e.g.  During a lightshow, there needs to be smoke particles present in the air otherwise you dont see the laser beams.
• A shadow forms when objects block light rays. 

Why is the sky blue?

• Light form the sun is scattered 

        when it enters our atmosphere. 

• This is called diffuse light. 
  
• Blue is scattered more than  

       the other colours, and 
       therefore the more prominent colour.

Activity 8 (p. 30)

We do it differently

Use the fluorescent tube above you as lightsource, and your hand as an object

Types of shadow

• Partial shadow: A shadow that 

       receives light from more lightsources.

• Full shadow: The light from all lightsources is stopped by the lit-up object.
  
• For work spaces sharp shadows are unpleasant. That is why they are usually equipped with fluorescent tube lighting. 
  

Types of light beams

o Point source: Light comes from one place.
o Divergent light beam: 

    Light rays spread out.  

                                 (point source)
o Parallel light beam: 

    Licht rays dont spread out. 

                                      (laser)

With a divergent light beam all light comes from one point.

1. True
2. False

With a parallel light beam the shadow is always the same size as the object.

1. True
2. False

With a divergent light beam the shadow is the same size as the object.

1. True
2. False

You can never see light rays.

1. True
2. False

Partial shadow is the area where no light reaches.

1. True
2. False

How can we see light?

1. Reflection
2. Diffusion
3. Parallel
4. Dispersion

Explain why the sky is blue.

Which part of the drawing is partial shade?

A

B

C

1. A
2. B
3. C

What kind of light beam was used to make this presentation?

1. divergent light beam
2. parallel light beam
3. convergent light beam

Do the following questions:

20 t/m 23 (blz. 24)

In your writingbook

Rules: 

- 10 minutes

- No talking

Finished early: search more shadow theatre on youtube, and see what you can say about the kind of light beam they use.

21 a en b, zie diagram op volgnede pagina

What did you
learn today?

In a nutshell:

• You can only see light when it is reflected. 
• Shadows apear when light is blocked by objects. Partial shade forms when some light is blocked, but still other light raches the area where the shadow forms.  
• With a divergent light beam, light spreads out

       and with a parallel light beam 

       the light rays run parallel to each other.