Milk colouring

Today me and my mum were doing science experiments.
The experiment we did was when you put milk in a bowl or a plate then add different food colouring to the milk. Then you get a cotton bud and put a bit of dishwashing liquid on it. After you put the dishwashing liquid on the cotton bud you can put the cotton bud anywhere you like. The dishwasher liquid pushers the food colour and it colours the milk.

The colours I use was green purple and gold.
here is a photo after I put the dishwashing liquid in.


 

Pepper vs dishwashing liquid

I was learning water tension.
I found it hard to put the dishwashing liquid on m finger so I used a cotton buds. 
next time I would use less pepper and a bit more dishwashing liquid. 

What does the dishwashing liquid do to the water surface?
It moves the pepper to the side of the plate.