What in the Rock is this?

Ingredients:

• Pre-made Pancake Mix (like Krustez) with vanilla for taste (It may be easiest to make it in a Ziplock bag and cut off a corner for pouring).
• Chocolate chips (Generic brands (not Toll House) have a low enough melting point that they illustrate the layers and smear through the pancake)).
• Mini Marshmallows (Become sugar lined cavity).
• Raisins or Dried Cranberries (The fruit will not change when heated).

Materials:

• Pancake mix was made ahead of time in a plastic Ziplock bag. Use a pair of scissors to snip off a corner and pour the batter through the hole.
• Pancakes: Bowl for making mix, if not pre-made ahead of time, Pancake griddle, Extension cord (if needed) or Stove, Silverware, Plates, Napkins, Wet wipes, Spatula, Non-stick cooking spray, Garbage bag, Hand sanitizer, Paper towels
• Examples of rocks or pictures:
  • Illustrate transformation of limestone into marble for Metamorphic rocks. Consider bringing in a piece of marble tile.
  • Sedimentary rock or rocks with layers +/- fossils
  • Lava rock or pumice for Igneous rock example
  • Other distinctive rocks can provide an interesting discussion like petrified wood, granite, quartz, geodes, etc.
• Calcite test demo: Clear plastic cup, few tablespoons of baking soda, approximately 1/2 cup of distilled white vinegar

Procedures

• Tell the students that we are going to make pancakes using three items that will represent crystals or grains within our “mystery rock”. We will act like geologists to use deduction to figure out what kind of rock our pancake represents
• Start by reviewing the difference between a rock and a mineral. A mineral is made of only one type of material where a rock can have mixed types. Precious gems or birthstones can be minerals.
• Discuss the types of rocks and review how the rocks are formed (Rock cycle).
  • Sedimentary— Imagine a leaf falling into the water of a pond. Eventually, it sinks to the bottom and more and more leaves and dirt end up on top of it over time. Over millions of years, the increased heat and pressure from the ground will form sedimentary rocks. When sticks, bugs, and fish skeletons settle into the mud, they become part of the rock as well.
  • Igneous—Lava rock and pumice come from volcanos and are formed depending on how quickly the molten rock cools.
  • Metamorphic—Formed with heat and pressure. Have kids rub their hands together to create friction as a model for how tectonic plate movement would create heat and pressure. They should notice that the pressure and movement of the hands create heat. An example would be a jet of molten rock moving through sedimentary, metamorphic or igneous rock. It melts the surrounding rock and changes it into something different. This process can turn ordinary sandstone into marble like they see in fancy buildings or their grandmother’s bathrooms.
• Review the ways that geologist identify a mineral and have kids give suggestions. The answers might include the tests below: streak, Calcite (vinegar/acid), hardness/scratch, physical properties, metallic sheen or cleavage (breaking with a hammer).
• As an example of the Calcite test, add an inch of vinegar to a clear plastic cup. Add about a tablespoon of baking soda (NaHCO3) to demonstrate the fizzing. Tell the students that you have are adding a powdered mystery rock to some vinegar. They should tell you this represents a Calcite test.
• Make one pancake per child. Ask each child what they would like in their pancake but (unless there are allergies) they must have at least one of everything to get a full understanding of the lesson. This is their “Mystery Rock”. The ingredients represent crystals or grains with in the rock. Tell them that before they can eat, they must be scientists and be sure to examine the top, bottom and cross sections of their pancake to determine what happened to all the ingredients with heat and pressure.
• Have them start at the mystery rock rectangle on the left hand corner and ask them to answer the questions on the flow chart, i.e. Do you see layers? Yes or no, then follow the lines to the next box.
• Once they circle their answer or describe what they deduced from the flow chart to an adult, they can eat. It can be more fun if you hide the correct answer from the other kids at the table and allow the others try to figure it out on their own.