Soils
Lesson 12
How Water Moves Through Sand and Clay
Students pour water simultaneously onto sand and clay, and observe that water travels through these soil components at very different rates. This investigation models how rainwater drains quickly through sand while forming mud puddles on clay.
3. Lesson set up and Management
SYSTEMS 1.1-Properties: Understand how properties are used to identify, describe, and categorize substances, materials, and objects and how characteristics are used to categorize living things
GLE 1.1.1 Understand simple properties of common natural and manufactured materials and objects: Sort common materials and objects using a simple property and Identify and describe the differences between common natural and manufactured materials and objects using properties.
GLE 1.1.5 Understand physical properties of Earth materials: Sort rocks based on size, shape, and other physical properties and Explain how some Earth materials are used by living things.
SYSTEMS 1.2-Structures: Understand how components, structures, organizations, and interconnections describe systems
GLE 1.2.1 Understand that things are made of parts that go together: Identify the parts of objects, organisms, and materials and Describe how the parts of objects, organisms and materials go together and Construct simple devised to do common tasks using common materials and explain how the parts depend on each other.
INQUIRY 2.1-Investigating Systems: Develop the knowledge and skills necessary to do scientific inquiry.
GLE 2.1.4 Understand that models represent real objects, events, or processes.
- Models can be constructed to test scientific questions such as a filtration system model for soil drainage
- Different soils absorb water at different rates
3. Lesson set up and Management
Materials:
Fold the collar of the filter around the edges of the funnel to prevent collapse of the filter.
Mark the water level in the 30 ml cups with a grease pencil or permanent marker. This will insure that the same amount of water is being poured through each model.
Student Management:
Students often forget to place a cup under the funnel to catch the draining water. Be sure all have done this before water is poured into the system.
Stress the use of a dropper to pour the water onto the sand and clay. This will prevent spills and overflows
This lesson is an ideal opportunity to talk about variables. By marking the amount of water in the two 30 ml cups at the same level, students are making an attempt to control a variable - the amount of water. Discuss the importance of controlling all variables except one to insure a viable investigation. The variable being changed is the soil type - one model contains sand and one contains clay. The variable being measured is the speed at which water travels through each soil sample.
Writing Support:
Students can write about the variable being measured in the last lesson (the amount of water passing through the humus) and contrast it to the variable being measured in the this lesson (the time for water to pass through either sand or clay).
Variables are all the things that could be changed in an investigation. The variable measured is the aspect of the investigation that changes depending on how the investigation is run (depending on the manipulated variable).