A quick summary: when dish soap touches the milk (dyed to show the movements), the colours will spread outwards and swirl. From what I've heard, this is because the soap molecules are attracted to the fat molecules in milk. My question is how to quantify things (you can't exactly measure how fast it swirls). I was thinking of changing fat content and measuring the drops it takes before there is no movement, but there isn't much you can conclude afterwards. Any thoughts on how to approach this will be much appreciated.

Is there any way for you to dilute the milk to a point that you can, indeed, see the action? This may be the key to quantifying your experiment a little better. Of course, the addition of hydrogen and oxygen molecules might have to be accounted for.