Today in second grade humanities we discussed stratigraphy. We talked about how looking at the layers of the Earth is really important to archaeologists. We learned that the oldest layer is on the bottom and the newest layer is on the top. To demonstrate the concept, we built our own Stratigraphy Sandwiches.
Here are the supplies, just waiting for the kids to arrive:
The first thing the students did was set one piece of bread on their plate. The bread represented a field in Virginia.
Next, I told the kids that a flood (the field was near a river) had occurred, causing a layer of mud to settle over the the field. The kids spread a layer of chocolate frosting on the bread to represent the mud.
A group of Archaic people came to camp at the site. They left a circle of rocks from their fire pit and some charcoal from their fire. The students placed a circle of chocolate chips on the site to represent the rocks, and sprinkled sprinkles in the middle to represent the charcoal.
After a time, the Archaic people moved on, and a layer of dirt and rock covered the site. To represent the layer of dirt, the students placed another slice of bread on top of their “sandwich.”
Later, another group, this time the Powhatan, come to the site. They built shelters. The students used their knives to dig holes in the top slice of bread to represent the post holes the Powhatan dug in the Earth.
The Powhatan made pottery, some of which was broken or destroyed. The Powhatan dug holes and threw the broken pottery in the holes. To represent this, the students dug more holes in their bread and buried pieces of “pottery” (M&M’s) in the holes.
The Powhatan moved on. The proximity of the site to the river resulted in another flood. To represent the flood, the students spread a layer of blue frosting on top of their bread. For many of the kids, this resulted in some redistribution of the “pottery.” We talked about how this can happen at a real site, and how archaeologists need to account for this type of movement when they excavate and analyze artifacts.
Through time, I told the kids, other layers of dirt accumulated, until the present and final layer of dirt covered the site. To represent this final layer, the kids placed one last piece of bread on top of their sandwich.
This led us to present day, when an archeologist, suspecting that the field was a prehistoric habitation site, conducts random samples and surveys. The kids took samples of their own, randomly poking a straw through the three layers of the sandwich to see what they could find. When they came across a sprinkle, a chocolate chip, or an M&M, they knew that they had found an area that could have been a habitation site.
The archaelogist decides to conduct a test excavation at the site. To represent this, the kids cut a small square out of their sandwich and examined the stratigraphy of the square. It was easy to tell the layers apart. We talked about how it’s not always so easy in real life.
I asked the students what would happen if I put their sandwiches in a blender. Would they be able to examine the layers then? Could they tell which items were found where? They agreed that it would then be impossible to tell. We compared that to when a habitation site is bulldozed or looted.
What would happen to the sandwiches if we separated them, layer by layer, to excavate the contents within? They certainly wouldn’t be sandwiches anymore. This is true at excavation sites in real life — archaeology is a destructive process. Procedures at a dig are precise because once a site is excavated, it is destroyed. There are no second chances.
After all that working and talking, it was time to eat our stratigraphy sandwiches. If you thought the kids would hesitate to dig in to a three-layer frosting sandwich, you thought wrong.
All in all, we learned a lot and may have had a bit of fun along the way. A successful endeavor, if you ask me.
And apparently Grace agrees.