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OBJECTIVES:
Everyone loves !
But when you make these delicious chocolate no-bake cookies you also will
learn how asphalt is made and used in paving roads.
When asphalt is heated it changes from a solid to a
sticky liquid. Small rocks are mixed into the asphalt.
As the mixture cools the asphalt hardens. This asphalt and
rock mixture is much stronger than the original solid asphalt and
can be used for paving roads. Like the asphalt,
the chocolate you use in this recipe becomes a liquid when
heated. As you mix other tasty ingredients into your
"chocolate asphalt" you'll observe the cookies harden
and become stronger as they cool.
STEPS TO FOLLOW:
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Prepare the "chocolate asphalt" in advance.
In a medium size
pot combine the cocoa powder, milk, butter and sugar.
Heat, stirring frequently until the mixture boils for 2 minutes. Pour into
the crock pot set at highest temperature. Yields 2 cups (8 1/4 cup
portions). Double or triple as needed.
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Using the measuring cup and tablespoon, measure the following ingredients and
pour them into your mixing bowl or paper cup:
1/8 cup old fashion oats
1/8 cup quick oats
1 tablespoon walnuts
1 tablespoon coconut
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Compare the edible construction materials
to the pictures of the actual
asphalt construction
materials. List the similaries and
differences between the edible and real construction materials.
Consider
weight, roughness, thickness, overall size, porousity.
Real Asphalt Construction Materials
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Look at the liquid form of the chocolate asphalt in the crock pot.
When asphalt binder is heated to 300o F, it is also a liquid.
Using the ladle, spoon and measure 1/4 cup chocolate asphalt into the materials mixture.
Chocolate Asphalt Cookie
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MATERIALS:
Cookie Ingredients for 8 Students
1/3 Cup Cocoa Powder or Carob
1/2 Cup Milk
1/4 Pound Butter (1 Stick = 1/4 Pound)
2 Cups Sugar
8 Tablespoons Chopped Walnuts In A Plastic Bag
8 Tablespoons Flaked Or Shredded Coconut In A Plastic Bag
1 Cup Old Fashion Oats In A Plastic Bag
1 Cup Quick Cooking Oats In A Plastic Bag
Supplies:
Medium (2 Quart) Pot
Crock Pot Or Other Heat Source
Extension Cord
Large Wooden Spoon
Ladle
1/4 Measuring Cup
1/8 Measuring Cup
Tablespoon Measure
Water and Paper Towels for Clean Up
For Each Student:
Steep Sided Bowls or Large Paper Cup
Sturdy Spoons
Wax Paper Cut Into 12" squares
16 oz. Sealed Can or Rolling Pin
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Look at the picture of the drum mixer from the asphalt plant. It
tumbles all of the construction materials until they are well coated with
the asphalt binder. The tumbler works like a clothes dryer. Mixing
the ingredients in the bowls is a similar process.
Drum Mixer
Stir until all of the materials are well coated. Notice - the mixture cools
while you stir it, becomes stiffer
and starts to stick together. Asphalt behaves in the same manner.
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When the materials are thoroughly mixed, pour the mixture into a mound
on a square of
wax paper. Cover with a second piece of wax paper.
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In the field, the pavement is spread with a paver and then rolled into
a thin mat with a roller. The roller is very
heavy and pushes all of the air out of the pavement. This helps make
the asphalt very strong. Use a can or rolling pin to
roll your cookie mixture 1/4"-1/3" thick. Can you still identify
the different materials in the cookies?
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Place your hand over the top of the cookie. Do you feel the heat?
When asphalt pavement is first rolled out it is still very hot.
Just like the asphalt,
the cookies will harden as they cool. (Do you think that the cookies
would be as strong if you use less edible materials? More edible materials?)
When the cookies have cooled and hardened (20-30 minutes),
you can peel off the wax
paper and eat. Congratulations!
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