The CHEMISTRY of Ice Cream 

Michelle Seeley

Elmont Memorial HS

Summer Research Program for Science Teachers

Summer 2006

AIM:               How can we utilize chemistry concepts in making ice cream?

OBJECTIVES:

·        Investigate the effects of temperature change on phase changes

·        Investigate the effects of changes in freezing point

·        Utilize the law of conservation of energy

·        Apply these concepts to make ice cream!

Do Now:         Students will answer pre-lab questions utilizing prior knowledge.

Questions are designed to get students thinking about energy changes involved in ice-cream production.

Procedure:    After we go over pre-lab questions on worksheet, we discuss the recipe.  Don’t give them the recipe, make your students use their brains.  But you should guide their brains before they start….  Here are some sample questions to ask them to make them think about their recipes:

              -Which of the 5 ingredients do you want IN the ice cream?  (milk, sugar, vanilla)

                        -Which of the 5 ingredients should NOT be in?  (ice, salt)

                        -Why are there 2 bags? (one for the “wanted” stuff, one for the other stuff.)

                        -How much of each ingredient goes into the ice cream?  (I only put out the proper size cups- so they have to figure out that its 1 cup milk, 1/3 c. sugar, ½ tsp. vanilla.)

                        Here’s the recipe to refer to:

1.      In small bag, place 1 c. milk, 1/3 c. sugar, and ½ tsp. vanilla.  Seal up the small bag.

2.      In the large bag, get ice (fill just under halfway) and a scoop of salt.  Put the small bag inside the larger bag, seal it up.

3.      SHAKE.  Minimum of 10 minutes.

4.      Check for solidification.  If its done- clean up, get a spoon, and enjoy!  (while you answer the analysis questions.)  Be careful not to get the salt/ice mixture into your ice cream.

Assessment:  Students will answer the analysis questions in groups, and then we will discuss as a class.  The sugar always gets them to participate more enthusiastically!

Standards: 

In the new science as inquiry standards, the vision includes the "processes of science" and requires that students combine processes and scientific knowledge as they use scientific reasoning and critical thinking to develop their understanding of science.  In this activity, students apply prior knowledge and design their own procedures, which directly involves them in the process of science.

In terms of content, this directly relates to the physical science standards which focuses on interactions of energy and matter as critical pieces of knowledge.

Note:  this is a great culminating activity for a class.  It can be a little spendy for the teacher- about $50 for all of the supplies.  As an alternative, you could ask students to bring in $1 apiece, its worth it!  Its also very messy- be prepared with a mop and lots of paper towels.  It also helps if you have 1 or 2 kids who can stay after and help you clean up.