Pore Space

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Objective

SWBAT identify how pore space in soil components affects water retention in soil.

Big Idea

Each soil component holds different amounts of water.

Warm Up

10 minutes

To begin the lesson, I review the class anchor chart created in the previous lesson. I ask students to review the properties of each soil component. This review activates the students' prior knowledge and increases their chance of success in today's lesson.

Student-Conducted Lab

40 minutes

In the port space lab, students will create a scientific drawing of each soil component, add water to the soil components, and determine how much water is held by the soil components. To start, each student group gets a sample of gravel, sand, clay, and humus. They add the soil components to a graduated cylinder and use a stick to push the soil components down until the graduated cylinder has 20 mL of the soil component. The students then predict where the water line will be in the graduated cylinder after they add 30 mL of water. Next, the students add the water and compare their predictions to their results. Finally, the students pour the water out of the graduated cylinder to see how much water the soil component holds. The students record their observations and results on the pore space lab worksheet. A sample of a student's completed work can be found here. A video of my students engaged in this lab can be found here.

Closing

10 minutes

To close the lesson, I assign each student group one soil component. I ask the student groups to present their findings (where the water line was, how much water was returned) for their assigned soil component. I record the students' findings on a class chart and we use this chart to discuss any outliers or surprising results.