Chromatography

Ink magically splits up into different colours!

Equipment:

1. Newspaper or tissue
2. Markers
3. Cup of water

Procedure

1. With a pencil draw line 2 cm away from the edge of the paper.
2. Mark a spot in the paper just above the line with the marker given.
3. Place the paper in the cup of water so that the pencil line is above the water line.
 What colors do you see on the paper?
4. Leave for 10 mins.
What colors are seen now on the paper? What was the color of the marker you used?

Check out the results of kids who have different coloured markers.  Is the colour on the paper the same as the colour on the marker used?Why do you think the color took time to spread to the paper?

Explanation:
The color in the dot dissolves in the water. The water is moves up the paper by capillary action. The different inks which make up the marker color move at different speeds and so they are separated.

At the 'molecular level' smaller hydrophilic molecules migrate faster through the paper. Hydrophilic means a "water-loving" substance, as opposed to hydrophobic compounds which are not soluble in water. Cooking oil is an example of a hydrophobic substance. The colors that move the fastest have smaller molecules than the ones that move slowly.

FOR EXHIBITION

Black ink is made of many colors.  We can show that by using the above method.

Use black marker to make the dot on the paper and place the paper in the cup such that the dot is above the water. 

We wait for the water to move up the paper through capillary action.

As the water moves up so do the different colors.

The different colors move up at different speeds.

This is because some colors dissolve in water faster than others.

We can use this method to separate the colors of many different things.

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