Light and color

• Natuurkunde
• Middelbare school
• havo, vwo
• Leerjaar 2,3

Light and color

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Light

You can explain what is meant with a spectrum

You know the difference between natural and artificial lightsources

You can explain what determines the color of an object

You know what is required to be able to see an object

You can explain the difference between real and imagines colors

You know the difference between lightabsorption and lightreflection

The prism

Making a rainbow

The spectrometer

HET KLEURENSPECTRUM

Can you explain this?

What is happening with the light?

What does this tell you?

The spectrometer

Every lightsource has a different spectrum.

You can only see this through a spectroscoop.

Just compare some different lightsources:

candalescent lightbulb, fluorescent tube, a candle

day light, a burner with a yellow or blue flame,

a sodium lamp or a blacklight

Info

What are you going to do?

Compare the spectrums of different lightsources

Make a drawing in your notebook and try to explain with words what you see and how these spectrums differ from each other.

Questions:

What lightsource(s) give a continuous spectrum?

What lightsources have a clear emission spectrum?

Make a rainbow at home

Wat zie je?

Maak in je schrift een tekening van wat je hebt gezien

What do you need?

• sunlight
• a long tall glass
• a leave of white paper
• water
  

What do you need to do?

• Fill the glass with water.
  
• Put down the glass into the sunlight.
  
• Wait until the water isn't moving anymore
• Move the piece of paper around the glass and try to catch a rainbow

Make your own spectrometer

What do you need?

• some kitchenpaper

• an empty cd rom

•a piece of black cardboard  (1 mm dik, 5 cm x 5 cm in size)

• some duct tape and some normal tape

• a pencil, a scissor and a sharp knive

Step 1: the slit

1. Take a piece of cardboard, put the roll of kitchenpaper on top and draw the circumsize of 
2. the kitchenpaper tube on the cardboard. Then cut out this circle of cardboard. 
3. Cut the circle through the middle to get to exactly the same halves.
4. Glue one of the halves with some tape to the end of the kitchenpaper tube
5. Glue the second halve next to the first one with a smal slit in between.
   The slit should be approximately 0,5 millimeter in size
6. Use duct tape to put both halves in place at the end of the kitchen paper tube.
   No light may enter the tube, except through the slit itself

plaatjes

Step 2: the slit

1. Take an empty cd rom and cut it into 4 quarters.
   
2. Put the pieces with the label up on your desk.
3. Use a knive to cut off the inner and outer part of the cd rom, leaving onlu the labelled part
4. On top of the label you put some duct tape.. 
5. Leave no air bubbles underneath the duct tape and rub the tape to make sure it sits tight 
6. Pull the tape of again. The label should be pulled away by the tape and the cdrom should
   be partly or completely transparant by now. Try not to tough the part of the cdrom where
   the label was residing before.

pictures

see also

This link

Step 3: putting the spectroscoop together

1. Draw to lines across the length of the kitchen tube to mark the direction of the slit
2. Put the kitchentube with the slit down on your desk
3. Then turn a piece of the cdrom with the label side down on top of the other
   end of the kitchentube 
4. Turn the piece in such a way that it resembles the picture shown
   
5. The way the cdrom is turned in relation to the slit is very important.
   Make sure that a transparant part of the cdrom is in front of the middle of the tube.
6. Fix the piece of cdrom with two pieces of tape
7. Cut of the outer edges of the cdrom piece
8. Then fixate the piece of cdrom with ductape, while leaving the middle slit free
   

pictures

The colorspectrum

Met een spectroscoop kan je achterhalen uit welk materiaal een ster bestaat.

The Rainbow

De regenboog

^{What colors do you see??}

^{What is the order of the colors ?}

^{Can you explain how a rainbow comes to live?}

^{Maak een aantekening in je schrift}

A drop of water can cause the same effect as a prism.

It will cause the "white" light to split up into different colors.

wat bewijst dit eigenlijk?

Mixing colors

Mixing colors

Watch how the colors mix

Make a drawing in your notebook

Name each color

Light is mixing differently compared to paint

What explanation is given by your teacher?

SIMULATION

Observing

To be able to see depends on numerous things.

Seeing something is very different from observing something. Seeing somethinig is often done unconsciously. Observing is done consciously while interpretting what you see.

Welke kleuren worden geabsorbeerd door een rood oppervlak?

1. Rood
2. Blauw
3. Geel
4. Groen

Waarom zie je bij maanlicht
geen kleur

1. Staafjes zien geen kleur
2. Kegeltjes zien geen kleur
3. Er is geen kleur aanwezig

Voor welke kleuren zijn de kegeltjes
in het oog NIET gevoelig

1. rood
2. geel
3. blauw
4. geen

De meeste kleurenblinden kunnen geen rood en groen onderscheiden.

1. Waar
2. Niet waar

Onder een gekleurde lamp kunnen gekleurde voorwerpen zwart lijken.

1. Waar
2. Niet waar

Met drie kleuren kun je alle kleuren van de regenboog maken

1. Waar
2. Niet waar

Een kleuren televisie werkt met rode, gele en blauwe pixels.

1. Waar
2. Niet waar