Time
Day 1: Optional: 5 min discuss soil observation homework from last night 10 min observe samples of different soil ingredients 30-40 min conduct soil quality tests
Day 2 (several days later): 15 min complete observations of Tullgren Funnel and soil separation tests 30 min discuss results and draw conclusions about "healthy" versus "unhealthy" soil
* Since the Tullgren Funnel and soil separation tests take several days, it is recommended to start Day 1 on a Friday and complete Day 2 on a Monday. *
Grouping
2-3 students
Materials
For each group of students:
- 4 petri dishes
- 2 funnels (card stock paper rolled and taped into a funnel shape and cut to 4-6 inches tall may be substituted)
- 2 funnel holders to hold funnels upright above a Petri dish (card stock paper rolled into a tube works well or you can eliminate the Petri dish as well by using a cup that the body of the funnel rests in as long as the bottom tip of the funnel does not touch the bottom of the cup)
- 2 square of cheesecloth
- 2 strips pH paper
- 2 white paper towels
- 2 clear 15 ml tubes with lids, glass or plastic
For whole class to share:
- Clay in ziplock bag
- Sand in ziplock bag
- Silt in ziplock bag
- Compost in ziplock bag
- 8 large plastic cups
- 8 plastic spoons
- 2 graduated cylinders
- 2 tablespoons
- 2 rulers
- 2 different types of soil (The more different the texture, composition, and organism content of the 2 soils, the better. For example, try soil from the school yard vs. store-bought potting soil, a clay soil vs. a sandy soil, or rich garden soil vs. soil from an abandoned lot.)
- 3-4 bare light blubs hung or mounted approximately 1 foot from the table top (desk lamps work well)
- 1 small jar alum (available at supermarkets for pickling)
- 2 magnifying glasses
- 1 package removable dot labels or rolls of masking tape
Setting
classroom