The Milk Lab

This week our professor gave us a group experiment using a small beaker, a petri dish, 3 different colors of food coloring, milk, and detergent. We were first instructed to put 30 mL of 2% milk into the petri dish. Next, our group placed a drop of each color of food coloring in the points of a triangle. We observed this for 30 seconds and noticed the darker colors spread a lot more. Then we put a drop of detergent in the middle and watched the action begin! All the food coloring in the milk was repelled from the detergent to the side of the petri dish. Once again, we observed, but needed to try some other things to see what was going on. So, we tried this same experiment four more times, but changed something every time. In trial two, we changed the order to detergent, food coloring, and then milk. The same reaction happened, but at a slower rate and the coloring was repelled from the bottom of the petri dish. Trial three we used water instead of milk and the same thing happened. In trial four, we delayed the time between the food coloring and detergent which led to a stronger reaction. Finally, trial five we used warm milk which resulted in our strongest reaction yet! The food coloring not only repelled from the detergent, but it hit the walls so hard that it bounced back and mixed together into the art pictured below. Through our different experiments, we figured out that time, temperature, and order all play a factor in how strongly food coloring reacts with detergent.