Edible Soil

Bedrock – Oreo cookie in the bottom of the cup.

Bedrock is solid rock. Parent material is formed from the bedrock after a long weathering process. There are two basic ways that weathering can happen – physical and chemical. Physical weathering includes things like wind or water erosion, glacial activity, freezing and thawing, and biotic activity (plant roots, animals, micro-organisms). Chemical weathering includes leaching, oxidation, carbonation, and hydration.

Parent Material – Crumbled cookies as the next layer.

This is the C horizon in a soil profile. It is called the parent material because it is the weathered rock and partly weathered soil from which the soil layers above are formed. What influences does the parent material have on the other horizons? (Size of the particles would determine the texture of the soil.)

Subsoil – Vanilla pudding as the next layer.

This is the B horizon from the soil profile. Why is it lighter in color than the A or O horizons? It is lighter in color because it has less top soil and organic matter.

Topsoil – Chocolate pudding as the next layer. Add a gummy worm to the pudding.

This is the top layer of soil. Nutrients, bacteria, fungi, and small animals are abundant. Plants thrive in it because of the nutrients in it.

Litter – Sprinkles on the top.

The sprinkles represent the organic matter. This layer is usually less than an inch thick. Litter decomposes into nutrients that enrich the soil. In areas where the temperature is lower, the composition of organic matter is slower.

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