What do you think will happen when detergent is added to the middle of a Petri dish of milk with drops of yellow, red and blue food colouring in the corners?
Draw a picture of what the Petri dish looks like before and after you add the detergent.
Can you explain what you see?
What happens with milk and no detergent, with water and detergent, with skim milk and detergent with cream and detergent?
Which works best?
What do you think will happen if you used vinegar instead of detergent?