Schadow

Shadows
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Slide 1: Tekstslide
NatuurkundeMiddelbare schoolhavo, vwoLeerjaar 2,3

In deze les zitten 41 slides, met interactieve quizzen, tekstslides en 5 videos.

time-iconLesduur is: 50 min

Onderdelen in deze les

Shadows

Slide 1 - Tekstslide

You can explain the difference between point sources and big lightsources
You can explain what causes half and full shadows
You are familliar with the concepts of divergent, convergent and parallal lightbeams
You can explain lunar and solar eclips 
You can replicate lunar and solar eclipses using a drawing
You can explain the different phases of the moon
You can explain why we have different seasons 
You can explain the difference in lightintensity during different seasons


Slide 3 - Tekstslide

Schadow

Slide 4 - Woordweb

In the early days when there were no computers, smartphones or other high-tec gadgets, people did find a way to enjoy themselves using light and shadow. Oldfashioned and boring? Perhaps, but we make use of it even now and people are still enjoying the playfull way we use light and shadow together.

Slide 5 - Tekstslide

Slide 6 - Tekstslide

Slide 7 - Tekstslide

Slide 8 - Tekstslide

Schadow
"Schaduw comes to life if the light of a lightsource is wholy or partially blocked by an object. A precondition for having shadows is that you need a lightsource and a blocking object.

Furthermore, you can differentiate in the kind of lightsources which can be divided into natural lightsources (like the sun) and artificial lightsources (like a man made lamp).
wikipedia
poem

Slide 9 - Tekstslide

Light and shadow
You need light to see shadows

Light rays travel in straight lines

Schadows exist in places 
were light is blocked

Slide 10 - Tekstslide

Different kind of lightbeams

Divergent lightbeam: 
Lightrays move away from each other
They seem to orginate from one point  
                     
Parallel lightbeams:  
Lichtrays stay at equal distance

Convergent lichtbeam: 
Lightrays are focussed on one point

Slide 11 - Tekstslide

Pointsource or Large lightsource
pointsource
A pointsource is a lightsource for which assume that all light originates from a very small point. In reality this often is not the case since most lightsources are most of the time bigger than a small point of light.
big lightsource
If the lightsource is very big, the object will receive light from multiple angles which results in different shadows.

Slide 12 - Tekstslide

Different kinds of shadows
  • Half shadow (penumbra): 
    A shadow which still receives partial light of the lightsource
  • Full schadow (umbra):
    A shadow which receives no light at all
  • Workingspaces are better for working if you do not have a lot of sharp shadows. Therefore we make use of large fluorescent tubes.

Slide 13 - Tekstslide

Peculiar schadows
Where are the lightsources?

A stadium needs a lot of light to make all shadows dissapear

Nice how a shadow give you another look at things
Would this be during the day or at night?
Why do you think so?

Slide 14 - Tekstslide

Slide 15 - Video

This is how red, green and blue mix

Click on the picture for an overview


Colored light sources will provide nice shadows

Slide 16 - Tekstslide

Blue sky
Sun& solar eclipses

Slide 17 - Tekstslide

Why is the sky blue?


Watch the video and make a note
about why the sky is blue

Slide 18 - Tekstslide

The moon will be in different phases during a month. This has to do with the orbit of the moon around the earth and how the moon is situated to both the earth and the sun.

Slide 19 - Tekstslide

Slide 20 - Video

Corona
another word for the circel around the sun during a solar eclips
but now famous 
for something 
completely 
different

Slide 21 - Tekstslide

Slide 22 - Video

explanation
The sun is very big in relation to the earth.
Therefore you do not draw it like a point source.
And if you do not have a point source you will get full and half shadows.

Slide 23 - Tekstslide

explanation
This picture makes clear that when the sun is shining at an angle (which especially is the case during winter time), the liughtintensity is far less because the same amount of light is spread over a larger distance.

Slide 24 - Tekstslide

Seasons
The axis of the earth is always at an angle relative to the sun.

Because of this summer and winter will take turns with each other on the northern and southern halves of the earth.

Slide 25 - Tekstslide

Slide 26 - Video

Slide 27 - Tekstslide

Slide 28 - Tekstslide

A couple of colors is prjected onto a screen.
Drag the colors to the right spot
Black
Green
Yellow
White
Magenta
Blue
White

Slide 29 - Sleepvraag

Who is nearest to the screen?
A
The girl
B
The mother

Slide 30 - Quizvraag

Slide 31 - Video

Where do you find a halfshadow?
A
B
C
A
A
B
B
C
C

Slide 32 - Quizvraag

Explain to me why the color of the sky is blue?

Slide 33 - Open vraag

Why can we see light?
A
reflection
B
diffusion
C
parallel
D
dispersion

Slide 34 - Quizvraag

At the spot where you see a halfshadow,
there is no light
A
True
B
Not true

Slide 35 - Quizvraag

You cannot see light rays
A
True
B
Not true

Slide 36 - Quizvraag

The shadow of an object is bigger than the object itself with a divergent lightbeam.
A
True
B
Not true

Slide 37 - Quizvraag

Slide 38 - Tekstslide

Slide 39 - Tekstslide

Slide 40 - Tekstslide

Light is moving in straight lines does it not?
Keep in mind that light has wave like properties. Because of this, light can bend around a corner when it goes through a very narrow opening. You do not have to remember this, this is more something for higher education. But it is nice to know that strange things can happen.

Slide 41 - Tekstslide