MAGIC MILK ART: WHAT ARE PHENOMENA? AND A WINTER STEM INVESTIGATION

​Natural phenomena are observable events that occur in the universe and that we can use our science knowledge to explain or predict.  The goal of building knowledge in science is develop general rules, based on evidence, that can explain and predict phenomena.  Despite their centrality in science, phenomena have traditional been a missing piece in science education, which too often has focused on teachers passing on general knowledge that students can have difficulty applying to real-world contexts.  By centering science education on phenomena that students are motivated to explain, the focus of learning shifts from being told about a topic to figuring out why or how something happens.  Students work through figuring it out because they are wondering how it works.  If we simply give students the scientific knowledge, we kill the wonder.  Don’t kill the wonder!
 
 
Magic Milk Art Investigation
 
PHENOMENON:  How does soap get greasy dishes clean?  Better yet, how does dish soap get greasy ducks clean?

Click here to observe the phenomenon.
 
This activity involves demonstrating a supporting phenomenon and then attempting to explain it by designing an investigation.  Post a photo of your students in action in our comment section or post a comment on how you modified the activity to work in your classroom.  
 
This phenomenon may be used for the following NYSSLS standards:
 

• MS-PS1-2. Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred. (Patterns)
• MS-PS1-8. Plan and conduct an investigation to demonstrate that mixtures are combinations of substances. (Patterns)

• HS-PS1-3. Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles. (Structure and Function)

 
Students in elementary grades may likely not be able to explain in scientific terms what is happening.  Allow them to draw their explanation or explain in their own vocabulary.  The important part here is the wonder.  With younger kids, they don’t need the real explanation at this point.  
 
MATERIALS:
 

• Shallow, flat-bottomed plate or baking dish
• Milk (dairy)
• Food coloring
• Dish soap
• Cotton swab sticks (Q-tips)
• Small cup (bathroom cups or condiment cups work great)

• Cookie-cutters in fun winter shapes (optional)

 
 TO DEMONSTRATE THIS PHENOMENON:
 
STEP 1: Start by pouring your milk into a baking dish or other flat bottom surface. You don’t need a lot of milk just about ¼ of an inch. Then if you have one, place a cookie cutter in the milk. Allow the milk to settle before moving to the next step.
 
STEP 2: Next you want to drop some coloring onto milk (outside of the cookie cutter).

STEP 3: Pour some dish soap into the small cup.  Dip your cotton swab tip into the dish soap so the cotton is coated in soap. Then bring it over to your milk dish and gently touch the swab to the surface of the milk. What happens?
 
 DEVELOP AN INVESTIGATION:
 
Can you explain how this phenomenon works?  
 
OPTION 1: Change the milk. Develop a data table and try repeating this experiment with different types of milk and liquids (skim, 1%, 2%, whole milk, half & half, heavy cream, or even plant-based milks or water, vegetable oil, olive oil, canola oil, etc.).  
 
OPTION 2: Change the soap. Develop a data table and try repeating this experiment with different types of soaps (shampoo, liquid hand soap, laundry detergent, or bar soap). 
 
What happens? Do you get the same effect, or does it change?  Which liquids produce the most dramatic effects?  Does it help you to explain how this phenomenon works?
 
Can you explain how dish soap gets greasy pans or greasy ducks clean?  
 
Teacher Hints and tips:

1. You can reload new cotton swabs and touch the milk as many times as you want - Eventually the movement will stop.  You can try holding the swab in the milk longer, or putting the swab all the way to the bottom of the dish.
2. Multiple colors can be used for more fun.
3. Example Data Chart setups:
4. *Spoiler alert* Click here for the scientific explanation of this experiment.  This link also contains lots of other fun STEM activities!

By: Kelli Grabowski, CA BOCES Learning Resources​