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Observations: |
- How many different rock layers are in your sample of cake? Four one for each color. Some samples may only have 2 or 3 layers there were missing layers in their small core sample.
- What color is the top rock layer? Yellow or white - Some students may count the sediments on top of the cake as a layer. Clarify the difference between sediments and rock. Let them feel the powered sugar and a piece of cake.
- What color is the bottom layer? Blue with poppy seeds- Some student's samples will have a different color on the bottom.
- What color batter did you pour in first? Yellow or one without food coloring
- What colored batter did you pour in last? Blue with poppy seeds.
- How did the slice of cake compare with the core samples? The cake slices show a swirled design while the core samples showed bands or layers one on top of another.
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Analysis: |
- Using the Law of superposition for your sample of cake label the layers from youngest to oldest. The top layer would be the youngest. The yellow is on top.
- In what type of rock did you find fossils? Sedimentary. The blue layer is limestone and contains fossils or poppy seeds.
- Based on the kind of rock the fossils are found in where were they formed? Explain why. Limestone is formed in ocean water. So these fossils were probably formed in the ocean.
- What type of rock is under the sediments or soil? Sedimentary. The key says yellow cake is sandstone- Some students will have igneous or metamorphic rocks on top and will have to explain how they got there. If you dust off a part of the cake a yellow layer will be on top except where the red food dye - volcanic activity is at the surface.
- Explain how the green layer formed. Since the green cake is a metamorphic rock called quartzite according to the key, the layers above put pressure on the rock and the igneous rock below could have given heat to change the sandstone into quartzite.
- In which layers were volcanoes active on the surface of the cake? Explain why The red cake is igneous rock so when the third layer was at the surface of the earth there was volcanic activity. If your piece of cake has a red plume of cake the igneous intrusion may come to the surface in the green or yellow layers.
- If these cake layers were originally formed in the pan give at least one deformation that happened to the layers. If the yellow layer went in first and the blue went in last then the oldest layer would be the oldest and the blue the youngest. So in the baked cake the layers have been turned over or deformed. If your cake slice has a red swirl or uneven layers or mixing of colors they are all deformities. The entire slice of cake shows changes much like those in metamorphic rock. There is folding, foliation, overturning, subduction..
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Rock Layer Key
1. Red |
2. Yellow or white |
3. Green |
4. Blue |
Igneous Rock |
Sedimentary rock |
Metamorphic rock |
Sedimentary rock |
Basalt |
Sandstone |
Quartzite |
Limestone |
5. Poppy Seeds |
6. Powdered sugar |
7. Brown powder |
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Fossils |
Sand |
Soil |
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Follow up: |
Have the students make a cake in a square or rectangular pan. Insert cardboard covered in tin foil and have them create a cake with tilted layers, Missing layers and intrusions or mixed layers. Have them ice and decorate their cake and then hunt for the unconformities. (You can also challenge them to create a checkerboard cake with 3 round cake pans, cardboard covered with aluminum foil and chocolate and yellow cake mixes- accept all entries. They will cause a lot of discussion and will taste good no matter the effect.) |
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