This week, the students wanted to uncover what soil would be best for their plants from The Black Oak Savannah. This led them to question how soil is made. Our classroom character Felicity the Fairy left us a recipe for soil. Together in a jar we combined rocks, organic matter, water and air. When we read the next instruction we were shocked! We found out that for these materials to turn into soil we would have to wait 1000 years! This led to one student questioning whether anyone other that our fairy friend was immortal so they could guard the contents of our jar.
The students inferred that for our ingredients to turn into soil, the rock and organic material would have to break down. Luckily, Felicity the fairy left us two science experiments to show us how rock can break down over time.
The first experiment instructed us to put a piece of chalk in vinegar. Chalk is a soft, white, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite. The vinegar was meant to represent concentrated acid rain. When the chalk/rock was put into the acid rain it began to slowly break apart. Over time acid rain has a similar effect on rock.
The second experiment required us to put a piece of chalk in water in the freezer. We learned that when water goes into the small cracks of this porous rock and expands while it freezes it breaks the rock apart.
We continued our research and found that rock can be broken down by weathering.
After we learned how soil is made, the students in room 101 went on to explore the components of soil. We used a song to learn that soil is made up of sand, silt, humus, rock and clay. To make this lesson a little more fun, the students first had a chance to examine clay, sand, silt, humus and rock in different jars. They compared each component's texture and consistency.
Next, the students had the opportunity to make soil in a jar...using the following ingredients:
Marshmallows represented rocks.
Crushed graham crackers represented sand.
Chocolate pudding mixed with crushed graham cracker represented silt.
Chocolate pudding represented clay.
Crushed oreo cookies represented humus.
This was topped with a gummy leaf to represent organic material and a gummy worm to stand in as a decomposer!
Students then made a diagram of the components of soil and did procedural writing to explain how they made their soil cups.