Saturday, April 12, 2014

Colligative Properties - And Its So Tasty Too!!!

Colligative Properties - An Its So Tasty Too!!!

What if everyday your students came to the door of your chemistry classroom with ANTICIPATION and EXCITEMENT?

What if your chemistry students spent more time smiling in your class than grimacing with angst over another lecture or worksheet?

What if you couldn't wait to get to your chemistry class because you wanted to see how your students would respond to the activities you have planned for that day?

What if you made ICE CREAM and ate it in the science lab and students grasped the concept of freezing point depression and were excited about how to calculate colligative properties because they have an answer to the age old question of "When am I ever going to use this in life?

Well, this is just a tiny part of what I get to experience since adding FLIPPED LEARNING to my education environment. And while the flipped model is not a silver bullet for education, it is a means of creating a more engaging, hands on, student centered classroom.

Let's face it, freezing point depression and boiling point elevation in a lecture-worksheet classroom experience is not one of the most engaging pathways to student learning. But throw in a couple of baggies, some whole milk, whipping cream, sugar and vanilla, a whole lot of ice and some salt and all of a sudden you have smiles, laughter, cold hands, warm hearts and a great learning experience for students that will be part of discussions with peers and parents  and will be most definitely be part of discussions at 10, 20 and 30 year class reunions.  And isn't that when the students own the learning?  When they can articulate the experience beyond your classroom walls. 





So after students completed their flipped lesson playlist for colligative properties on SOPHIA we took a Friday afternoon and the following recipe and solidified our understanding of freezing point depression by making ice cream and a whole lot of smiles. 



  • 1/2 cup milk
  • 1/2 cup whipping cream 
  • 1/4 cup sugar
  • 1/4 teaspoon vanilla or vanilla flavoring 
  • 1/2 to 3/4 cup sodium chloride (NaCl) as table salt or rock salt
  • 2 cups ice
  • 1-quart freezer bag
  • 1-gallon freezer bag
  • themometer
  • measuring cups and spoons
  • cups and spoons for eating your treat!
Add the milk, whipping cream, sugar and vanilla to the 1-quart bag.  Squeeze out as much of the air as possible and seal the bag. Place the sealed bag into the 1-gallon bag and surround it with the ice. Pour in the salt and seal the 1 gallon bag. Massage the contents until the ice has melted completely. Students may want to wrap the bag in a towel as the bags get very cold. 
When the ice cream has a texture and viscosity, open the 1-gallon bag, remove the 1-quart bag, discard the melted ice and bag. Now grab a spoon and enjoy the fruits of your labor. 

The learning moments abound as students question, "Why does the ice get so cold?" and,  "How does the liquid thicken?"  But I think the best question is, when they ask, "Can I do this at home?" Because then, I know that I have got them!!!!  And I know they will be coming back for more!!!