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What Is Soil Made Of?

Author(s): Nancy Moreno, PhD, and Barbara Tharp, MS.

Session 2: Soil Texture

Each group will need a soft drink bottle (with cap) and the second half of its soil sample. Ask students to describe the different components of the soil they investigated during the previous session. Tell them that now they will observe the make-up of soil in a different way. 

Instruct each group to add about 1/2 cup of soil and 1/2 teaspoon of alum to the soft drink bottle, and then add water until the bottle is 3/4 full. If students have difficulty pouring soil into the bottle, show them how to make a paper funnel by rolling a sheet of paper into a cone shape. Direct students to cap their bottles tightly and shake the bottles for about one minute. 

Next, have students place their bottles in the center of their group work areas and observe how quickly or slowly the different types of particles settle. When layers are visible at the bottom of the bottle, have students measure and mark the layers, and draw their observed results on their “Soil Observations” sheets. 

To facilitate accurate measuring, you may want to instruct students to fold a sheet of paper lengthwise, hold it against the side of the bottle, and mark the boundaries of each layer on the paper. 

Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

My Health My World: National Dissemination
Grant Number: 5R25ES009259
The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698, R25ES06932