Place a considerable amount of dishwashing liquid in a square bowl - big enough to either take a size A4 or A5 paper - add water and stir and shake the water up to make lots and lots and lots of bubbles. (It is recommended not to use a straw as this mixes the colours together and that is not what you are wanting)Gently drizzle some colouring on top of the bubbles. You can drizzle them in a pattern or just any how. Use a few different colours.
Then gently place the paper on top of the bubbles and count to about 5. Lift the paper and "walah" you have the Northern Lights!