Science, Physical Science

Grade 3- 5

Objective

Students experiment with properties of frozen food.

Directions

The concept of baking ice cream mystifies students and is a wonderful science activity too! Follow the directions below (which also appear on the activity sheet) to bake the ice cream.
Heat the oven to 500 degrees Fahrenheit (260 degrees Celsius). Cover a baking sheet with aluminum foil.
Beat egg whites only with an electric mixer until they form soft peaks.
Add sugar to the egg whites, 1 tablespoon (45 mL) at a time, beating with the electric mixer until the mixture is thick and glossy. This is meringue.
Place cookies on the baking sheet. Cover each cookie with some frozen ice cream. Make sure the ice cream fits without hanging over the cookies.
Spread meringue thickly all over the ice cream. Make sure there are no exposed spots of ice cream.
Bake in oven for 2-3 minutes until meringue is lightly brown.
After you have taken the cookies out of the oven, show them to students. Have them answer the questions on the activity sheet.
When they have finished answering the questions, give them the explanation for why the ice cream did not melt.
The meringue acts as an insulator, just like insulation in a house or coat. The meringue has small air spaces trapped in it which slow down the passage of heat and cold. Beating the eggs makes lots of bubbles in the meringue. When you spread it over ice cream, it insulates so that the heat of the oven cannot get in during the short time it is in the oven.
Tell students that if meringue was permanent and did not melt, you could probably use it to insulate your house. Imagine living in a meringue house!

Resources

• Baking Ice Cream activity sheet (one per student or group)
• oven or toaster oven
• 3 egg whites
• 1/2 cup sugar
• 1 cup (240 mL) ice cream
• baking sheet
• aluminum foil
• mixer
• big, thick, hard cookies (Chinese almond cookies work well)