Initial Publication Date: January 13, 2021

Engage: Soil is Charged!

Part A. Phenomena: Soil has a Charge

Introduce the unit with the following soil charge demonstration. The purpose of this activity / demo is to get students thinking about soil chemistry and charge. Set up the demo and let it run for a few minutes while distributing other materials.
Soil Charge Demonstration
Time required: 15 minutes 
BIG Idea 1: Soil nutrients are chemical elements. 
Ask the Essential Question: 
What are the most essential elements in our soils and in our foods? 
Key point: 
Nutrients, in the form of ions, move around in the soil and are essential to life.


Part B. Everything is Chemical

After intriguing students with the demonstration, show the short, animated video from University of New Mexico which describes how everything we consume is built from chemicals. Everything is Chemical

Everything is Chemical

Following the video ask students:

  1. Which 4 chemical elements make up 95% of all plants and animals?
  2. Where are these elements found in the soil?
  3. Name 5 types of Inorganic Matter found in the soil. Why are these elements important?
  4. How do the sugar chains in potatoes differ from those in corn stalks?
  5. How do farmers use chemistry?
    1. Which 4 chemical elements make up 95% of all plants and animals?
      Answer: C, H, N, O
    2. Where are these elements found in the soil?
      Answer: Organic Matter
    3. Name 5 types of Inorganic Matter found in the soil. Why are these elements important?
      Answer: Si, Al, S, Mg, P, K 
      These elements are nutrients for plants and animals.
    4. How do the sugar chains in potatoes differ from those in corn stalks? 
      Answer: Potatoes have straight-chained sugars, known as starches, while corn stalks chains are rotated sugars making them stronger and indigestible for humans.
    5. How do farmers use chemistry? 
      Answer: The science of chemistry helps to prevent over-fertilization and water pollution.


Part C. In Search of Essential Nutrients

In this segment of the activity, educators will use the Nourishing the Planet High School materials. These excellent and comprehensive materials include teacher background pages, activity masters, and numerous support materials. Educators will need to create a free log-in to download the materials in PDF. Nourishing the Planet High School Materials


Time required: 45 minutes 

Step 1. Handout the Activity Masters 1.2, 1.3, and 1.4 (Periodic Tables) from Activity 1: Essential Elements 
Ask students to list the essential elements needed by plants and explore how they compare with those needed by humans.

Step 2. Follow lesson plan in Lesson 1 Nutrients for Life Activities, stop after Master 1.4.

Step 3. Extend this lesson by showing students Table 4-1 from the Know Soil Know Life book and discuss how nutrients are both anions and cations. (Note: depending on the level of the students this may need more scaffolding.)

Step 4. At the conclusion of the lesson, return to the Soil has a Charge battery demonstration and ask which ions are attracted to which terminal of the battery and why? Review the concept of anions and cations.