Chocolate Chip Cookie / Rock Cycle Module

Chocolate Chip Cookie/Rock Cycle Module Created by Tania Deisher, September 2005

Materials, Day I:

12 oz bag of chocolate chips (semisweet) Non-stick baking sheets, greased Stove or hot plate Saran wrap Non-stick pot, lid Refrigerator Several plastic spoons Hot pad

Prep work, Day I: Before class, melt down 12 oz bag of semisweet chocolate chips on a hot plate or stove. Allow the chocolate to cool some before bringing the pot into the class (so that they will solidify faster on the baking sheet, rather than spreading out and making a mess). Place the covered pot of chocolate on the hot pad in a stable area.

In Class Activity, Day I: QUESTION TO CLASS: Where do rocks come from?

GUIDANCE: Think about what you’ve learned about the core of the earth… How is the core of the earth connected to the surface that we walk on? (Volcanoes!) What happens to lava when it cools? What kind of rock comes from a volcano? IGNEOUS - Examples of igneous rocks? pumice, obsidian - Density example with pumice = only rock that floats.

OBJECTIVE: The first type of rock in the rock cycle is igneous rock, which forms when lava cools (both above and below the earth’s surface).

ACTIVITY: Provide each student with their own spoon. Ask them if they have an idea what the melted chocolate might represent based on the previous discussion. Have each student dip their spoon into the chocolate and make a few “igneous rocks” on the greased baking sheet.

Reiteration: What are the rocks called that form when lava cools?

“HOMEWORK”: For Thursday, think about the rock dissections…those rocks were made of more than one mineral. If the chocolate chips are one kind of mineral in a chocolate chip cookie rock, what would be some other minerals?

Post-work, Day I:

Cover the baking sheet with saran wrap, label the sheet appropriately (do not eat!) and leave it in a refrigerator until Thursday. Clean up.

1 Chocolate Chip Cookie/Rock Cycle Module Created by Tania Deisher, September 2005

Materials, Day II:

Stack of heavy books ½ stick butter, softened Spatula ½ cup brown sugar, packed Measuring cups / spoons ¼ cup granulated sugar 2 Mixing bowls 2 large eggs, at room temperature Wooden spoon ½ teaspoon vanilla Non-stick baking sheets, greased ½ teaspoon baking powder ¼ teaspoon baking soda COOKIE RECIPE (makes 2 dozen): ¼ teaspoon salt 1 1/8 cups Flour “Igneous” chocolate chips

Prep Work, Day II:

Have ingredients and measuring utensils organized. Get “igneous” chocolate out of refrigerator and scrape off of baking sheet with a spatula into a bowl. Wash baking sheets well and re-grease.

In Class Activity, Day II:

QUESTION TO CLASS: Are there other rocks on the earth besides igneous rocks? Examples?

GUIDANCE: Think about the dissection rocks. Were they made up of the same minerals? Our chocolate igneous rocks are made up of one mineral, but how is a rock with more than one mineral made?  The dissection rocks are an example of a SEDIMENTARY ROCK.

QUESTION #2: How do sedimentary rocks form?

Explanation: When igneous rocks are broken off by wind or water, the pieces eventually end up in streams. Small pieces of different kinds of rock and other material (sand, etc) are called SEDIMENT. Over a long period of time (10,000 years or more), layers of sediment end up on top of each other.

Think about a single page in a book. One page isn’t heavy at all but if you put all of the pages in 10 heavy books on top of each other, whatever is at the bottom of the book stack gets squashed. That is what happens to sediment. Have a student volunteer come to the front of the class. Place a single page on the student’s hand and ask if it is heavy. Continue to place books on top of the student’s hand until they agree that it is heavy. Note that it takes hundreds or thousands of pages to be considered “heavy.”

Eventually there is so much weight on top of the lowest layer that the ingredients in the lower layer start to get pressed together. The kinds of rocks that form when different minerals are pressed together for a long period of time are SEDIMENTARY ROCKS.

2 Chocolate Chip Cookie/Rock Cycle Module Created by Tania Deisher, September 2005

QUESTION #3: If cookie dough represents a sedimentary rock, what are the “minerals” (flour, chocolate chips, eggs, sugar, butter, vanilla, etc)?

OBJECTIVE: Sedimentary rocks form from pieces of rock and other materials (sand, shells, etc) that are compressed under heavy pressure for a very long time and are the second step in the “rock cycle.”

ACTIVITY: Have students wash hands thoroughly. Write the ingredients on the board as students list them off and put the appropriate measurement for the recipe next to the ingredient. Add any other ingredients not named by students. Have the students add the proper amount of each ingredient to the mixing bowl (dry in separate bowl than wet ingredients – mix each separately, then mix together). Ask for a few volunteers to take turns mixing. What does the stirring represent in the context of our cookie dough sedimentary rock? (The pressure that brings all of the minerals together.) Have the students help make cookie dough balls on the baking sheets.

Reiteration: What are the rocks that form from different minerals under pressure for a long time called?

“HOMEWORK”: For Tuesday, think about what changes when we put the cookie dough in the oven. Is it the same? Would a sedimentary rock be the same if you cooked it?

Post work, Day II:

Cover the baking sheets with saran wrap, place in refrigerator. Clean up.

3 Chocolate Chip Cookie/Rock Cycle Module Created by Tania Deisher, September 2005

Materials, Day III: Oven Oven mitt Napkins Timer Spatula (Milk) Cookie dough (Day II) Cooling rack (Dixie cups)

Prep Work, Day III: Take cookie dough out of refrigerator with enough time to warm up a bit. Preheat the oven to 350 °F.

In Class Activity, Day III: QUESTION TO CLASS: If you cook a sedimentary rock is it the same? Why or why not? If you cool a sedimentary rock is it the same? (The dough was refrigerated…) **Ask someone to be a timer. Put the cookie sheet in the oven for 15 minutes. ** SCIENTIFIC METHOD DISCUSSION (while the cookies cook) QUESTION #1: Who has heard of the scientific method? What is it? What are the steps? List them on the board. 1. Observation: 2. Question: 3. Inference (what you see): 4. Hypothesis: 5. Experiment: 6. Results: 7. Conclusion: QUESTION TO CLASS: If I want to use the scientific method regarding what happens to sedimentary rocks when they are cooked, where do I start? Help me fill in the 7 steps… **Remove the cookies from the oven and place on cooling rack in front of the class.** QUESTION #3: What do you see? Are they the same? What changed? Explanation: Metamorphic rocks form when igneous or sedimentary rocks get super- heated (and squashed). The heat cooks the rock and changes it – like cookie dough turning into a cookie.

Once metamorphic rock is formed it can get broken off into pieces by wind and water and end up in sedimentary rock again and then a new metamorphic rock. This is the idea of the rock cycle (important to note it takes a REALLY LONG TIME!).

QUESTION #4: Ask the class to explain the rock cycle to you (reward is cookies!)

Post work, Day III:

Make any notes to improve lesson for future use. Clean up.