Land and Water
Lesson 9
When Steams Join: Modeling Tributaries
Students will use their stream tables to model a multiple stream system. Students will then compare their results with other groups.
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 observe and record the results of using the stream table to model a three-source stream system.
- Students will discuss how a model is different than observing a real stream system.
3. Lesson set up and Management
Materials:
- Blue food coloring is not necessary.
- If drawing the aerial view: Make sure the clear plastic sheeting is cut large enough to cover the top of the tub and overlap so the rubber band can secure the plastic to the tub.
- If drawing the aerial view: Check to make sure the markers are not dried up.
- Consider taking a photograph of the stream tables for each of the groups.
- Try to move the stream tables as little as possible.
Student Management:
- Make sure the students accurately follow the procedure and accurately draw the aerial drawing.
- During the investigation, have students discuss the speed of the water and how the earth materials are being deposited. Consider using the toothpick flags from Lesson 7.
- Have the students discuss which earth materials are being exposed at the different points on 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 effect of the number of water sources on aerial drawings of the stream table model?
- Predication: Write a prediction for the investigative question, including the changed variable (single-source, multiple-source) and measured variable (observational data from the aerial view)
- Materials list:
stream table model
stream table set-up
2 liter bottle with water
cup with 3-holes
- Procedure:
- Set-up stream table as in lesson 7.
- Pour 2 liter of water into the 3-hole cup.
- After water has flowed through the stream table make an aerial drawing of the stream table (or take a photograph).
- As a class collect and display the pictures of the stream tables from each of the groups from Lesson 4 and Lesson 9.
Because of time it may be difficult for each group to do repeated trials. By having each group "share" their photos with the whole class, this is 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:
Flow of the Water
Group 1
(Trial 1)Group 2
(Trial 2)Group 3
(Trial 3)etc
1-hole (Lesson 4)
3-holes (Lesson 9)
- Conclusion: Have the students write a conclusion. Make sure the students answer the investigative question, provide observations from the pictures of the stream tables to support their conclusion, and explain how the data supports their conclusion.
- Remind students to make their block of soil, (step 1 on the "When Streams Join: Students Instruction for Modeling Tributaries" sheet) the same as in other lessons.
- Make sure that a different student in this investigation than in the other investigations is pouring the water and holding the catch bucket. If you are going to have students observe other groups'’ stream tables while the streams are flowing (Procedure 4), students will need to share the jobs of holding the catch bucket and pouring the water.
- Have different students in the group work on this aerial drawing. OR consider taking a photograph of the stream table results.
- If drawing the aerial view: Encourage students to use lines or other symbols to shade in an area instead of coloring the whole area a solid color.
- If drawing the aerial view: Some of the shading or filling in an area can be done once the clear plastic is removed.
Writing Support:
- Have the students make an aerial drawing or glue the copy of the photo into their science notebook. Have the students label where the water moved fast/slow and where soil was washed away or deposited (lesson 7). Also have the students label the land features (Lesson 8).
- Have the students write out the investigation process.
Reading Support:
- Have students research about the watershed that they live in. Have them compare their stream table with their watershed (the biggest difference will be the lack of mountains or significant elevation changes in the stream table).
- Read-aloud or independent reading opportunity: A New True Book: Rivers by Norman and Madelyn Carlisle. The teacher’s edition background section tells about a divides role in a watershed. This book does an excellent job of describing this on pages 10-13. It also describes the formation of rivers and the role of dams.