Land and Water
Lesson 14
Plants: Protecting Sloped Land from Erosion
Students will investigate the question, "What is the affect of plants on the amount of earth materials (sediment) collected in the graduated cylinder?"
3. Lesson set up and Management
INQB: Scientists plan and conduct different kinds of investigations, depending on the questions they are trying to answer.
INQC: An experiment involves a comparison. For an experiment to be valid and fair, all of the things that can possibly change the outcome of the experiment should be kept the same, if possible.
INQD: Investigations involve systematic collection and recording of relevant observations and data.
INQF: A scientific model is a simplified representation of an object, event, system, or process created to understand some aspect of the natural world.
ES2C: Erosion is the movement of Earth materials by processes such as wind, water, ice, and gravity.
- Students will identify the parts of the stream table system.
- Student will do an investigation to see if plants make a difference in erosion.
- Students will write a conclusion to the investigation.
3. Lesson set up and Management
Materials:
- Considering planting the seeds over the weekend. Make sure you water them well and cover stream tables with plastic wrap or the 3-mil, clear plastic sheeting used to draw the results of a stream table investigation.
- Make sure the plants fill in the entire surface area of the stream table.
Stream table after water flows through
with the plants.
- Label both graduated cylinders before starting the lesson. One is labeled 14-A and the other 14-B.
- Make sure the students are careful when they remove the plants from the center section of the stream table. Be careful to minimally disrupt the soil’s surface area.
- When the students are removing the grass from the middle of the stream table, have them collect the grasses onto a double thickness of paper towel, and the throw the paper towel into the garbage can.
- Beware, if you leave the plants too long, they can start to mold and smell.
Student Management:
- When making the science notebook drawing of the stream table system, have the students examine the rye grass and mustard to include in their drawings. If they can see the root formation along the side of the clear plastic box, please add this to the drawing.
- Have the students label the slope in the stream table.
- Have the students write an investigation for this lesson (individually or as a class).
- EXAMPLE of an INVESTIGATION
- Investigative question: What is the affect of plants on the amount of earth materials (sediment) collected in the graduated cylinder?
- Predication: Make sure the students include the changed variable (plants or no plants) and the measured variable (amount of earth material collected in the graduated cylinder).
- Materials list:
stream table model
stream table set-up
2 liter bottle with water
graduated cylinders
- Procedure:
- Set-up stream table as in Lesson 13.
- Pour 1 liter of water into the 1-hole cup.
- When the 1 liter of water is almost finished, collect a sample of runoff into the graduated cylinder marked 14A. Fill the cylinder to the 50-ml mark if possible.
- Remove a section of plants from the middle of the stream table (see illustration TE p. 177).
- Pour the rest of the water into the stream table. Try to keep the water at the line on the cup at all times.
- When the bottle is almost empty, collect another cylinder of runoff in the cylinder marked 14B.
- On record sheet 14-A, "Investigating the affect of Plants on Erosion" do step 1. Note the volume of earth materials (sediment) collected in the graduated cylinder.
- As a class, collect each group's data into a data table similar to what is below.
Because the students are removing plants from their stream table, it is difficult for each group to do repeated trials. Have each group "share" their sediment results with the whole class as a time-saving way to get repeated trials. Because the students are using each others' data, this may be a time to discuss "intellectual honesty" and how important it is to control procedural variables.
- Data:
Stream Table
Ground CoverGroup 1
(Trial 1)Group 2
(Trial 2)Group 3
(Trial 3)etc
Average
Plants (14A)
No Plants (14B)
- Conclusion: Have students write a conclusion. Make sure students answer the investigative question, provide data from the data table to support their conclusion, and explain how the data supports their conclusion.
- Extension 1 could be done as an investigation. The investigative question could be, "What is the affect of different types of soil (sand, gravel, humus, clay) on plant growth?"
- Extension 2 could be done as an investigation. The investigative question could be, "What is the affect of different soils from our neighborhood on the growth of plants?"
Writing Support:
- Prior to doing the activity, have students draw the stream table system with the plants in their science notebooks. Have them label the parts of the system.
- Have students write their own prediction for this investigation in the science notebooks. Also, have students write their own conclusions using the class data.
Math Support:
- Have students determine the fraction or proportion of sediments to the total amount of material in the graduated cylinder.
- Have students determine the fraction or proportion of the different types of sediments to the total amount of material in the graduated cylinder.