How to Make a Geologic Column Sandwich

When the lesson is finished, you can eat the column sandwich.

Making a geologic column sandwich is an educational, fun way to elaborate about how layers of different rocks have formed over millions of years. The geologic sandwich is multilayered, using a variety of ingredients that are representative examples of the age of the rocks; the "oldest" is at the bottom of the sandwich. The best thing about making a column sandwich is you get to eat it afterward.

Things You'll Need

• 2 slices rye bread
• 2 slices sourdough bread
• 2 slices wheat or multigrain bread
• 2 slices white bread
• Knife
• Butter
• Chocolate spread
• Shrimp
• Lettuce
• Turkey slices
• Peanut butter
• Cheese
• Jelly
• Tomatoes

Instructions

1. Spread a thin layer of butter on one side of all the slices of bread. Select one of the slices of bread as the base for the geologic column sandwich. A slice of wheat or multigrain is a good choice as it is made from the most natural ingredients.

2. Put a layer of chocolate spread onto the bread. This can represent single-cell organisms that lived on earth millions of years ago.

3. Place a slice of bread on top of the chocolate. Put a layer of shrimp on top of the bread. Explain that early versions of today's shrimp were on earth 500 million years ago.

4. Place another slice of bread on top of the shrimp and put another sandwich filling on top. Evaluate the age of the filling, or the age it represents. For example, lettuce can represent vegetation that rotted to make coal more than 300 million years ago, while turkey can represent the age of the dinosaurs.

5. Continue to build your column sandwich by using ingredients such as peanut butter, cheese, jelly and tomatoes. Place the last slice of white bread on top. Use a sharp knife and carefully cut through the multilayers. Separate the two columns so the students can clearly see the layers.

Tips & Warnings

• You can use any ingredients you desire. You can also and make your column sandwich taller.

• Put two or three fillings between each slice of bread or overlap different breads to give a different rock formation like sandstone, chalk or limestone. You can use the slices of bread in any order, as different types of rock form at different times and you often find that the same type of rock appears more than once.

• Draw a sketch of the column sandwich on a sheet of paper to offer students a record of what each layer represents. Label each ingredient, what the ingredient or layer of bread represents and the approximate age.

References

• Holt Science and Technology: A Geologic Column Sandwich
• British Council: Sedimentary Sandwich