Edible Soil

Today, we made edible soil to identify the layers of soil. 

The first step in turning rock into soil is that it must be broken down into sediments–small pieces.Rocks can be broken down (wind, water, ice, plant roots, people, etc.) The sediments are piled up. It’s not soil yet...it needs more. 

To demonstrate the bedrock layer, we crushed a vanilla wafer. Seeds germinate and plant roots grow in this dark-coloured layer. It is made up of humus (decomposed organic matter) mixed with mineral particles. Organic matter is plants and animals, which die and start to decay in the soil. Organic matter is mixed with the sediment. 

To demonstrate the subsoil layer, we mixed chocolate chips and marshmallows with pudding. We smoothed it over the wafer. The top, organic layer of soil, is comprised mostly of leaf litter and humus (decomposed organic matter). To demonstrate the topsoil layer, we layered crushed chocolate cookies and then poked a gummi worm through the top to peek out of the “soil.” Green cut Twizzlers resemble grass.

We mixed the edible soil to simulate the addition of another important component to soil - air. As air must be added to mixtures or baking will look like a pancake, soil is the same way. It needs air. That is why gardeners or farmers dig or plow or till soil before planting. Air is added to the sediments and organic matter over time. The last thing we need to make the soil is time. It needs to set. Soil also needs time. It is not nearly as fast as the Edible Soil. It takes half an hour to make. Soil takes hundreds of years.