Emulsifying Experiment

[ender7x77]

I'm kind of new here and not the greatest biologist (i think this applies in this forum) and was wondering if users could possibly help me out with something that has been baffling me.

 

The other day my biology teacher for my Grade 12 Academic class showed us a little experiment involving homogenized milk, food colouring, and detergent. I'm aware that the milk is mostly comprised of water and contains some fats, that food colouring is water soluble, and that the detergent is an emulsfying agent (not quite sure what emulsion is), but that is were my knowledge ends. The experiment went like this: We took a petri dish and half filled it with the homogenized milk and let it sit for like two minutes. After it was left to sit, we took four different colours of food colouring and placed them in four different corners for each colour. Once that was done we took a single tooth pick and placed the end in some detergent and then took that end put it in the centre of the petri dish. This caused the food colouring to spontaneously disperse quickly to the edge of the corners and then disappear into the milk. A few minutes later the colours remerged and dispersed once again but slowly in a way that looked like a tie dye commericialswhere different streams of colours moved and swirled.

 

Well, i made up a hyothesis after conducting some research on the emulsion, which i am unsure about, and this is what i believe occured.

Since the detergent is a natural emulsifying agent it is suffice to say that as soon as it is in contact with the homogenized milk, it reacts instantaneously to its fat contents. This reaction is emulsion and causes colloid suspension. Surface tension caused by the addition of the detergent forces the food colour to disappear in the uniform white which is the milk. Since the food colouring is insoluble in the water makeup of the homogenized milk does not dissolve in it. This allows the colours to re-emerge completely as they were and stream across the petri dish

 

If anyone can add/explain why these things happen it would be greatly appreciated because i want to impress my teacher and dont avoid sounding condescending because the simpliest anwser is good too. Thanks.

 

PS- if you happen to know the properties of those 3 things (milk, food colouring, detergent