I love soil, it is super important to a lot of basic life functions, and it very pretty!Soils generally have different horizons. The topsoil (A) contain a majority of the nutrients. For more information on the different horizons, and what they do, visit the Soil Science Society for America page on soil horizons.

Most soil profiles have many different layers

One of my life goals is to promote K-12 education through informal education. I do this through food. Traditionally, I did this with pudding, but the horizons are very uniform. To replicate the crazy diversity found in actual soil (the waves and uneven-ness caused by erosion), I needed a better solution. Enter CUPCAKES! The baking can change the waves and colors of horizons, based on the way things are scooped (just like soil changes based on the materials that it comes from.

Finished Product in Cupcakes

Soil Horizon Cupcakes (serves 22-24)

• White cake mix (and associated supplies)
• White frosting
• Food Coloring
• Measuring cups
• Oven mitts
• Spoons
• Three bowls
• Cupcake tins and paper wraps

Steps

• Prepare cupcake mix by following directions on the box.
• The B horizon in most soils are the thickest, therefore, I put two scoops in the B horizon bowl, for each one put in the other two bowls. If you only have two bowls, remember, in some states, the B horizon is VERY deep.
• In the Southeast, most of the B horizons are orange or red in color, so we dyed that. For more information on other states, visit the NRCS State Soil Site. Remember, keep it simple!
• The topsoil is dark, so we colored that horizon brown (took some creative use of food coloring).

Felsic granite, which is where North Carolina Rock comes from

• The rock that the soils came from is a felsic granite, so the C horizon is rotten rock, so we dyed it a lighter pink, and mixed in a handful of mini chocolate chips.
• Take a spoon, and scoop in a little of the cupcake mix to the bottom. (It is ok if you run out  before the last tin), as I said, some C horizons aren’t near the surface. The surfaces don’t need to be uniform, dab a little in one cup,  a lot in others, etc.
• Once you have the C horizon gone, dab in the B horizon in. The sky is the limit to how much, (or none at all, if you wish).
• Dab the A horizon  on the top. It doesn’t have to cover the entire surface, as eroded soils have exposed B horizons.

Three different bowls for the three major horizons

• Bake your soil profiles! While it is baking, dye the frosting green.
• Once cooled, frost the profile (putting on the grass).
• While the students are eating, show them how the layers are, reinforcing that soils have multiple layers.

Extensions

If you cut off the top of the cupcake (at different positions), you can illustrate how cutting into the landscapes during construction changes the surface horizon.