Milk and Food Coloring Lab 8/22

Why does the milk interact with food coloring?

Hypothesis: The milk interacts with food coloring mainly because of the soap. Since there is fat and protein in milk, soap can bond with these molecules and form new chemicals.

Procedure

1.     Measure 10mL of the testing liquid with a graduated cylinder

2.     Pour the liquid into a pan

3.     Add 1-2 drops of red and blue food coloring in the liquid

4.     Add 1 drop of dish soap in the liquid

5.     Repeat steps 1-4 with different liquids

Materials used: Whole milk, skim milk, orange juice, coffee, water, Palmolive dish soap, food coloring (red & blue), stop watch, graduated cylinder, toothpicks, pan

First Experiment

Dependent variables: Interaction between liquid and food coloring

Independent variables: Liquid

Control variables: Food coloring, dish soap, the amount of liquid

In the first experiment, we used whole milk, skim milk, orange juice, coffee, and water to test the liquids’ reaction with food coloring after the addition of dish soap. We observed that whole milk, skim milk, orange juice and coffee created spirals with food coloring. Only water didn’t generate such reaction with food coloring.

Whole Milk vs. Skim Milk

Orange Juice vs. Coffee

Water

Second Experiment:

Dependent variables: Diffusion of food coloring

Independent variables: Liquid

Control variables: Time, food coloring, dish soap, the amount of liquid

Procedure

1.     Measure 10mL of the testing liquid with a graduated cylinder

2.     Pour the liquid into a pan

3.     Add 1-2 drops of red and blue food coloring in the liquid

4.     Repeat Step 1-3 with different liquids

In the second experiment, we paired up whole milk with skim milk, and orange juice with coffee. For each pair, we used stopwatch to observe the change of the food coloring with the liquid in one minute. As a result, the food coloring dissolved faster in whole milk and orange juice without the addition of dish soap.

Whole Milk vs. Skim Milk

Orange Juice vs. Coffee

Conclusion: Since the dish soap is controlled, the liquids would cause the difference in reactions. In this dish soap, there is a chemical known as degreaser or surfactant. The surfactant helps lower surface tension in bonding between both polar molecules and nonpolar molecules. With this chemical, fats and proteins are allowed to move freely, thereby creating spirals with the food coloring. In addition, we know that there is more fat and protein in whole milk than in skim milk. And the food coloring spread faster in whole milk than in skim milk. Therefore, we made our conclusion that the more fat a liquid has, the faster the food coloring can spread.