Yummy "rocks"

Three geological simulations that are good enough to eat.

Rocks are formed on and beneath the Earth's surface under a wide range of physical and chemical conditions. Generally speaking, rocks are combinations of elements with a definite chemical composition and a unique structure which are determined by the type and arrangement of their atoms. It's much too complicated for most elementary children to comprehend.

One good way to make rock formation more underable is to simulate the formation process through cooking.

Students create their own "rocks" by combining ingredients and using an oven to recreate the heat and pressure needed when real rocks are formed.

The benefits of this activity are:

* Hands-on - Students identify and mix ingredients that will be made into "rocks."

* Observation - Students see the ef fects of heat being applied to the ingredients. Gravity exerts the pressure that's needed to squeeze the melting ingredients together. After the "rocks" have been formed, they can be carefully dissected to see what happened to the ingredients as they fused together.

Nutrition - The "rocks," containing healthy ingredients, can be eaten.

Before we get started concocting our rock recipes, let's take a brief look at the characteristics of Metamorphic, Igneous and Sedimentary rocks.

Metamorphic. This is rock that has changed its appearance and sometimes its mineral composition. These changes may be caused by hot magma, pressure and heat from mountain-building movements in the Earth, or the chemical actions of liquids and gases. All kinds of rock, including igneous and sedimentary, have gone through such metamorphism to produce metamorphic rocks.

Igneous. Existing deep within the Earth is a molten rock material called magma Magma is under great pressure and is extremely hot (1,350 - 2,000 F or 749 -1,0930 C). Sometimes earthquakes (or deep movements in the planet) cause this material to rise to the Earth's surface through cracks or fissures. Also, the intense heat and pressure of magma can weaken the rocks above it and cause them to give way. When the magma rises to the Earth's surface, it spreads above the ground. As the magma mixes with the Earth's crustal material and cools, different types of igneous rocks are formed. Sedimentary. These rocks consist of materials that once were part of older rocks or of plants and animals. The rocks were deposited millions of years ago as strata (layers) of loose material. Most of the deposits occurred on ocean floors, but some appeared on land and in fresh water. As time passed, the loose materials changed into solid rocks.

To simulate how these three types of rock are formed, try the following easyto-make and easy-to-eat recipes.

You'll need the same cooking utensils for all of the recipes: an oven, measuring spoons and cups, a metal (or glass) baking pan (8" x 8" x 2" or 9" x 9" x 13/4" or equivalent), a large mixing bowl, a saucepan, stirring spoons, cookie sheet, 24 clear plastic cups (standard size) and a timer.

Metamorphic Rock Simulation Recipe

INGREDIENTS:

1/2 cup shortening or margarine, 1 cup brown sugar, 1/2 teaspoon vanilla, 1/2 cup dates or raisins, 1/2 cup chopped nuts, 1/2 cup well-drained crushed pineapple, 1 egg beaten, 1 cup whole wheat flour,1 cup flour, l teaspoon salt, 1 teaspoon baking soda. *

DIRECTIONS:

1. Cream shortening and sugar.

2. Add the beaten egg and vanilla.

3. Add the dry ingredients. Mix.

4. Stir in the fruit and nuts.

5. Drop teaspoonfuls of the mixture onto a cookie sheet.

6. Bake for 7 minutes at 375 deg F.

* Chocolate chips, wheat germ, currants, coconut, etc. can be added.

Igneous Rock Simulation Recie

INGREDIENTS:

1 6-ounce can evaporated milk, 1 1/2 cups sugar, 1/4 teaspoon salt, 1/2 cup chopped nuts, 1 1/4 cup tiny marshmallows, 1 1/2 cups semisweet chocolate pieces,1 teaspoon vanilla.

DIRECTIONS:

1. Grease an 8" x 8" x 2" or 9" x 9" x 13/4" pan.

2. Combine evaporated milk with sugar and salt in a saucepan. Bring to a boil. Reduce heat and simmer, stirring for 5 minutes.

3. Remove from heat. Add remaining ingredients.

4. Pour into prepared pan. Let cool.

Sedimentary Rock Simulation Recipe

INGREDIENTS: PART I

1 1/2 cups crushed Corn Flakes or other "flaky" cereal, 3 tablespoons sugar, 1 cup margarine.

DIRECTIONS: PART I

1. Melt margarine.

2. Mix with the cereal and sugar.

3. Press into a 8" x 8" x 2" or 9" x 9" x 1 3/4" pan.

INGREDIENTS: PART II

1 cup semisweet chocolate or butterscotch pieces

1 1/4 cup coconut

1 cup chopped nuts

1 14-ounce can sweetened condensed milk

DIRECTIONS: PART II

1. Sprinkle chocolate chips over cereal layer.

2. Sprinkle coconut over chips.

3. Sprinkle nuts over coconut.

4. Pour condensed milk over the layer.

5. Bake for 25 minutes at 325 F.

Extension Activity: Making Edible Fossils

MATERIALS: Standard size clear, plastic cups (one for each student, or one of each pair of students).

INGREDIENTS:

Jell-0 TM (at least four different flavors or colors), fruit (pineapple, apples, bananas, grapes, kiwi, papaya, strawberries, mandarin oranges, etc.) nuts.

DIRECTIONS:

1. Follow the directions on the package to make one Jell-O flavor.

2. Pour into cups.

3. Let set until slightly jelled.

4. Add one or two types of fruit or nuts for fossils.

5. Repeat, using different Jell-O flavors, fruits and nuts for each layer.

6. Draw and label the stratified layers on a sheet of construction paper.

This treat shows how the bottom layer is the oldest and the top layer is the youngest. Make predictions about the disappearance of apple chunks after the lime/grape era.

Mix some flavors! Brainstorm other foods that characterize various rock types. Have fun!

Curriculum Integration

Math measurements of baking time, liquids, solids, using teaspoons, tablespoons, cups, etc.

Home Economics - cooking (baking).

Language Arts - Students can read various books about rocks and minerals:

1. Chris Pellant, et al. Rocks and Minerals (Eyewitness Handbooks, DK Publishing, 1992).

2. Charles W. Chesterman (Designer). Familiar Rocks and Minerals of North America (Knop; 1988).

3. Byrd Baylor, Peter Parnall (illustrator). Everybody Needs a Rock (Simon & Schuster,1985).

4. Sandra Downs. Earth's Hidden Treasures (Earth Science Series, TFC Books,1999).

5. Rebecca Lawton, et al. Discover Nature in the Rocks: Things to Know and Things to Do (Stackpole Books, 1997).

John Cowens teaches science at Fleming Middle School, Grants Pass, OR, and is a Teaching Editor of Teaching K-8. E-mail: joco9@echoweb.net

Copyright Early Years, Inc. Apr 2000
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