Magic Milk Lab

Magic Milk

The purpose of our experiment was to determine if the “magic milk effect” is the same on milks with different fat densities and if the magic milk effect applies to other liquids which contain oil to some degree, like Crisco and coffee.

From our experiment we hoped to verify the correlation between the duration of motion of food coloring and the amount of lipids in each substance.

We used Dawn Original dish soap, dropped from the tip of a toothpick, for all four substances and added 3 drops of food coloring in a triangular formation. We stopped recording when the food coloring was no longer moving significantly.

Our first trial was with whole milk.

At 19 seconds into the video, the dish soap dropped into the 7ml of whole milk. The food coloring rapidly spread to the outer edges of the petri dish, with each drop of food coloring moving at approx. the same speed and in the same direction. The food coloring stopped moving after about 1 minute and 6 seconds.

Our second trial was with skim milk

At 17 seconds the dish soap dropped

The food coloring did not move to the edges as quickly as with the whole milk trial. The duration of the motion of the food coloring was 1:39 -0:17 = 1 minute and 22 seconds.

Our third trial was with coffee, and parts of the food coloring immediately moved towards the edges of the dish. There was little motion after the initial push outwards. The reaction took about 3 seconds.

Our last trial was with Crisco oil.

Instead of spreading outwards like the food coloring usually does, the dots grew bigger, then started moving towards the center of the petri dish. The three drops of food coloring collected into one big drop in the center, and stopped moving. The rest of the food coloring started to move towards the edges. The food coloring was probably sitting on top of the Crisco, and when soap was added the Crisco moved away from the soap, causing the food coloring to slip into the vacated space.

The explanation we present is that dish soap has two sides- a hydrophilic, polar, side and a hydrophobic, nonpolar, side. Soap weakens the surface tension of water by dissolving its hydrophilic side into water, in the process breaking part the dipole-dipole bonds of pure water. The other end of the soap disrupts the bonds that the lipids and proteins in milk have by attaching onto lipids. Soap clusters onto lipids, distributing the fat all around the solution, which is the reason food coloring would move in the first place, what makes the food coloring move so freely and exotically is that the original surface tension of water is no longer there to keep the food coloring in one place. Hence in Crisco oil the food dye didn’t spread because there was not much change in surface tension- which wasn’t based on water. 

Dolly & Anita