Lora Lee Hensel

Todd Weeks

TITLE: Heat, Not Temperature!

STANDARDS:

Science: Product - Heat

Process -- Analyzing, Evaluating

Math: Product -- Measurement, Fractions

Process -- Communication, Prediction

LEARNING STYLES: Gardner

Linguistic, math-spatial, kinesthetic, interpersonal, intrapersonal.

OBJECTIVES:

Academic: Each group will be able to describe how heat, salt, ice all affect how ice cream can be made.

Social: The student will learn to cooperate in a group lesson.

T CHART

Looks Like Sounds Like

Leaning forward Asking Why Questions

Eye Contact Good Job!

Nodding head in agreement Lets try that

STUDENT LEVEL: 5th grade

TIME REQUIRED: 25-30 minutes

BACKGROUND INFORMATION (see pages 33-34 in Science Text).

Heat is needed to melt ice. Thus, after the ice has melted, a gram of water has more heat than a gram of ice, even if the temperatures are the same in both cases. Heat that is needed to melt ice is called the heat of fusion. Students are not surprise to find that salt will cause ice to melt. They assume that the ice melts because it is warmed by the salt. But the temperature gets colder instead of warmer. The mixture gets so cold because of the heat of fusion. Heat is needed to change 1 gram of ice to a liquid. When the salt causes the ice to melt, a huge amount of heat energy is needed. That heat comes from the salt and ice, causing the saltwater to drop far below freezing. The forced melting of the ice has a cooking effect just like evaporation has a cooling effect. Heat is absorbed during the change of phase.

PREREQUISITE INFORMATION:

Student skills: How to work with a group

Experience measuring with a recipe

How to read directions

Know that salt melts ice

MATERIALS: eggs, sugar, half and half, vanilla, salt, milk, re-sealable plastic bags -- gallon and sandwich size, recipe card, mixing bowl, mixing spoon, spoons and cups for serving ice cream (# = number of students participating), crushed ice, worksheet.

GROUP SIZE: 4-5

INTRODUCTION OF LESSON: Ask the question, "What is required to make ice cream"? When the students have listed the ingredients with which they are familiar, then ask, "Did you know that heat if required to make ice cream"?

DEVELOPMENT OF CONCEPT:

• Explain to the students that heat is different from temperature. Lecture on heat. Include information on ice and salt. See background information.
• Direct the students attention to the recipe for ice cream that is on their tables. (see copy of recipe and mixing procedures attached)
• Place students into groups of 4-5
• Assign roles to the students, through handing out of color squares.

  Blue square: Reader (of recipe) and reporter

  Red square: Measurer (of ingredients)

  Green square: Bag Constructor (combining ice and salt in bag and sealing).

  Purple square: Recorder (of ingredients)

  Yellow square: Retrieves ingredients and cleans up

  All group members take turns mixing the ice cream

• Group members are to complete their tasks as dictated by the color square they received.
• Each group is to predict how long they think it will take for the ice cream to freeze and enter that guess on the worksheet provided.
• Students are then to form a circle (preferably not over carpet so that there is less problem if any dripping occurs). Students begin to continually move the ice around the inner bag of ice cream mix, trading between students every minute. (This trading is important, as the bag will get very cold).
• When the ice cream appears complete, each group is to return to their table to taste test their ice cream. While tasting, they are to discuss and then answer in writing the following questions on the worksheet provided.

  Would adding more ice cause the mixture to freeze faster?

  Would adding more salt cause the mixture to freeze faster?

  How would the absence of salt affect the freezing time?

They are also to note how long the ice cream actually did take to freeze and compare to their prediction.

POSITIVE INTERDEPENDENCE: All students must participate in the activity in order to complete the tasks in a timely manner. The bag movement must be done as a group to maintain rapid ice movement in order to complete the ice cream successfully with a minimum of discomfort to the hands. Each students required tasks are critical to the success of the final ice cream product.

INDIVIDUAL ACCOUNTABILITY: Each student must be a part of the experiment itself in order to have a more complete understanding of heat fusion at work.

CRITERIA FOR SUCCESS: Each group will be able to correctly answer the questions assigned (See Above), and have successfully created ice cream.

EXPECTED BEHAVIORS: Students will have successfully followed direction resulting in ice cream.

MONITORING: Observe the groups interactions and discussions to see if they are meeting both the social and academic objectives. During the ice cream making portion of the lesson, ask students "what is happening to the temperature of the bag"?, "what is happening to the mix"? "what is causing the mix to harden"?

PROCESSING: Ask groups to hand in their questions.

CONCLUSION: While the students eat the ice cream, they are to report on their findings, telling of their prediction of when the ice cream would freeze and what actually happened. They are to tell of one thing that they learned through this procedure.

Ask each student to double the recipe (they are then able to take that recipe home) .

EVALUATION:

Check that the doubling of the recipe was done correctly by each student.

Ask the group to place on their recorded sheet how well they worked together. (see attached sheet)

Read the group worksheets and evaluate for completeness of understanding.

EXTENSIONS:

When hot fudge is added to ice cream, why does it harden? Does the same process that causes the ice cream mix to harden cause the hot fudge to harden?

What makes the Magic Shell Ice Cream Topping harden so quickly?

RESOURCES:

http://ericir.syr.edu

Teaching Science to Children -- An Inquiry Approach by Alfred E. Friedl

Recipe for Ice Cream in a Bag

Place inside small bag:

1 beaten egg

_ cup sugar

1 cup half-and-half

_ teaspoon vanilla

pinch of salt

1 cup skim milk

Place inside large bag

crushed ice

_ cup table salt

Instructions:

1. Using any container and a fork, beat the egg.
2. Add sugar, half and half, vanilla and salt. Stir.
3. Add milk and stir well.
4. Pour mixture into small re-sealable bag
5. Partially fill large re-sealable bag with ice and table salt
6. Place small re-sealable bag into the large re-sealable bag.
7. Fill with ice.
8. Churn the ice cream. Ice is to be continually moved around the ice cream mix.
9. When the ice cream appears finished (has the texture of ice cream to the touch, becomes very obvious thorough the bag), place in cups and enjoy!

Please double the recipe ingredients below (if using this size recipe at home, use a quart size bag rather than the sandwich size for the ice cream mix):