Hooked on Science: Make ice cream in a zip-top bag

Thursday, July 5, 2012

Make homemade ice cream in a bag with a few ingredients and materials from around the house.

Ingredients and materials

* 1/2 cup half-and-half

* 1 tablespoon sugar

* 1/4 teaspoon vanilla

* 1 sandwich zip-top bag

* 1 gallon zip-top bag

* 3 cups crushed ice

* 1/3 cup rock salt

Instructions

STEP 1: Place the half-and-half, sugar and vanilla in the sandwich zip-top bag. Seal the sandwich zip-top bag.

STEP 2: Place the ice and rock salt in the gallon zip-top bag. Put the sandwich zip-top bag in the gallon zip-top bag. Seal the gallon zip-top bag.

STEP 3: Squeeze the gallon zip-top bag until the ice cream thickens.

STEP 4: Remove the sandwich zip-top bag from the gallon zip-top bag. Open the sandwich zip-top bag, using a spoon, taste your homemade ice cream.

Explanation

The salt lowers the freezing point of the ice and creates an extra cold brine that absorbs heat from the mixture. This causes the mixture to freeze creating ice cream.

Jason Lindsey is a science outreach educator with Hooked on Science. Check out his website www.hookedonscience.org for webcasts and experiments.

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