In this classroom experiment, students will experiment with how fat and soap molecules repel each other and how colors mix to make new colors.
Vocabulary words: primary colors, secondary colors
Key Concept: primary colors mix together to make secondary colors.
Context for Use
You could easily make this into a science lesson for older students. You could have them experiment with different fat contents in milk (skim, 1%, 2%) and different types of dish soap.
Resource Type: Activities:Classroom Activity
Grade Level: Primary (K-2)
Description and Teaching Materials
Dinner plate or coated plastic plate
Food coloring (red, yellow, green, blue)
Dish-washing soap (Dawn brand works well)
Cotton swabs (q-tips)
1. Pour enough milk in the dinner plate to completely cover the bottom and allow it to settle.
2. Add one drop of each of the four colors of food coloring - red, yellow, blue, and green - to the milk. Keep the drops close together in the center of the plate of milk.
3. Find a clean cotton swab (q-tip) for the next part of the experiment. Predict what will happen when you touch the tip of the cotton swab to the center of the milk. It's important not to stir the mix just touch it with the tip of the cotton swab.
4. Place a drop of liquid dish soap (the Dawn brand works well) on the tip of the cotton swab. Place the soapy end of the cotton swab back in the middle of the milk and hold it there for 10 to 15 seconds. Look at that burst of color!
5. Add another drop of soap to the tip to the cotton swab and try it again. Experiment with placing the cotton swab at different places in the milk. Notice that the colors in the milk continue to move even when the cotton swab is removed. What makes the food coloring in the milk move?
Since this is the introduction to the unit I will have the students use colors to indicate what colors mix together and the new color that was created. This will tie into the lesson for the next day on color mixing using pipettes and well trays.