Things you will need,
A bottle, food colouring, water, corn starch and paper/ a funnel.
Step 1: Boil Some Water, Measure One Cup of It and Then Pour It Into Your Bottle.
I recommend using a funnel for this.
Step 2: Measure 1/2 of Corn Starch and Pour It Into the Bottle As Well.
If you fold your paper and put the corn starch on it, its easy to get into the bottle.