Colour Detectives

What colours are really inside our felt pens?

This is the question that we asked ourselves as we conducted our experiment.

Students were given a strip of paper kitchen towel and asked to draw a straight line across the paper 2cm up from the bottom of the paper. Students were told that they were going to dip the paper into the water, but before they could do this they needed to make a prediction about what was going to happen. 

After dipping the paper in the water students sat and watched the magic unfold. As the water travelled up the paper it pulled the ink from the felt with it. Students with colour like light blue, yellow and red didn't see any changes to the color of the ink. Students with black, green and dark blue felts noticed something magical happening to the ink...it was splitting into a spectrum of colour. 

Shania wanted to know why the dark blue felt only had the colour spread up the paper, while the dark green and black felt ink spread up and down the paper? We looked at the colour spectrum created by the splitting of the colour in the ink. We noticed that the dark blue pen had purple, indigo and blue colours within its ink. We noticed that the black pen had violet, indigo,blue, green, yellow and red, there was a clearly seen blue line, did this mean that the black had more blue in it? We went back to our diagram of a rainbow to find an answer. What did we notice? That there are no colours under purple on the rainbow, is this why our dark blue felt pen only had colour spreading up the paper? Maybe.

We wonder if we would see the same colour spectrum for these colours in different brands of felt pens.. 

Making some observations

Dipping the paper