Problem Based Learning
Investigating the Effect of Rain on Land
Focal TEKS (Texas Essential Knowledge and Skills):
*Note: this unit was written for fifth grade, however, may be easily modified for several grades.
112.7. Science, Grade 5
(a) Introduction.
(1) In Grade 5, the study of science includes planning and implementing field and laboratory investigations using scientific methods, analyzing information, making informed decisions, and using tools such as nets and cameras to collect and record information. Students also use computers and information technology tools to support scientific investigations.
(2) As students learn science skills, they identify structures and functions of Earth systems including the crust, mantle, and core and the effect of weathering on landforms. Students learn that growth, erosion, and dissolving are examples of how some past events have affected present events.
(b) Knowledge and skills.
(11) Science concepts. The student knows that certain past events affect present and future events. The student is expected to:
(A) identify and observe actions that require time for changes to be measurable, including growth, erosion, dissolving, weathering, and flow.
Time: 2 hours
Materials:
For each group: stream table (shoe-box sized plastic box with dime-sized hole drilled in one corner for drainage); enough "land" to fill 1/3 of the stream table; "land" comprised of (2 parts) sand, (1 part) soil, (1 part) gravel, and (1 part) clay (preferably in powdered form) mixed together to model real land with a small amount (2 or 3 tablespoons for each stream table) of diatomaceous earth mixed in to keep "land" crisp; small trinkets such as Monopoly houses to represent homes; paint spatula; centimeter ruler; two-liter bottle with small holes drilled into cap; large pitcher full of water; permanent marker; 50mL beaker; bucket to catch run-off; hand lenses; newspaper to place under stream table and on floor to absorb spills; science journals; colored pencils
Safety Precaution: Diatomaceous earth can be harmful if inhaled excessively. Do not allow students to mix this ingredient in. Wear a mask to prevent inhalation. Once the powder is mixed in with the other components, it will not become airborne.
Procedure:
1. Conduct a discussion on what the land around us is comprised of (soil, sand, rocks, and clay). If necessary, consult the Harcourt Science textbook or other source with the class and read the proper section about land components. Discuss which components seem to be more prevalent in El Paso land (sand and rocks).
2. Tell students they will have the opportunity to build a model of the King's Hill Apartments today. Many professional such as geologist, engineers, and architects build models to use in investigations. Building a model of the apartments may be helpful in making their decisions of whether or not to build. Have one member form each group gather all materials needed. Have students cover tables and floor with the newspaper.
3. Tell students that they need to create a common measurement for their "rain source" (the two-liter bottles) so that each group will have consistency. We need to divide the capacity of the bottle into four equal parts. Have students offer suggestions. To do this with accuracy, we can use a standard measure, the beaker. Have students calculate how many mL comprise 1/4 of the bottle (50mL). Then, have students measure 50mL of water from the pitcher and pour water into the two-liter bottle. Mark a line with the permanent marker showing the measurement of 50mL. Measure and pour in 50mL more, recording the measure. Continue until all 2 liters are accounted for.
4. Allow time for students to examine the "land" in their stream tables. They may wish to use hand lenses. Ask what components they found. Explain that all four soil components mentioned before are present. Diatomaceous earth was added to keep the "land" crisp and dry, like our real land.
5. Tell students they will build a model of the mesa inside the stream table with the King's Hill Apartments situated on top. You may need to briefly revisit the aerial view of the mesa and apartment complex. The model should be built on the opposite end of the drain hole and take up less than half of the box. Use the spatula to push the land and shape it. Each group may mix in 20mL of water from the pitcher with the paint spatula to moisten their soil slightly to ease building. Place the buildings on top to model the apartment complex. Allow for differences among models, but be sure that guidelines have been met.
6. Students are to draw a picture of their model in their journals.
7. Allow students to take a brief "field trip" around the room, visiting each model briefly. They should check for similarities and differences among models.
8. Upon returning to their stations, have students make predictions within their groups as to what will happen when their models are "rained" on. Hypotheses should be recorded in journals. Groups may decide to agree upon a common hypothesis, or opt to predict individually. Have students also record the height in centimeters of theie original mesa (not including buildings).
9. Have groups situate their stream tables on the edge of the table, so the drain hole is hanging over the edge. Place the bucket under the drain hole. Demonstrate the proper way of making "rain" on the mesa. Flip the bottle upside down and gently shake up and down. DO NOT SQUEEZE the bottle. A gentle rain is desired. Be sure that all rain falls on the land. Once the concept is understood, instruct students to "rain" 50mL of water.
10. Record observations in journals. Students should include the amount of water "rained" in their entries. Pictures may be included, but descriptions are mandatory. A measurement of mesa height is also needed.
11. Repeat steps 9 and 10 twice more, releasing 50mL of rain at a time. Remind students to document the amount of rain released with each description.
12. By now, flooding and erosion should be evident. For the final 50mL "rain", allow students to squeeze the bottle, producing a stronger rain. Once again, record results. Allow students to take another class "field trip" to observe effects of rain for each group.
13. Discuss results with the class. Were hypotheses correct? Have students determine which geological processes were evident (weathering in a modified version, erosion, deposition). These processes should be listed in journals.
14. If students don't bring it up, use open-ended Socratic questioning to make the link to landslides. Open discussion for the relationship between this activity and knowledge learned/needed to make informed decisions. Example: we know rain plays a role in creating landslides, but how much rain is necessary? How much rain do places with frequent landslides get? How does this compare to the rain amount in El Paso?
15. Allow five minutes of response time in journals prior to clean-up.
Pedagogical Methods:
Collaborative grouping is imperative in this activity. Being able to discuss predictions and ideas with peers allows students to make new content connections. Class discussions throughout the activity gives students the chance to share ideas, building excitement. This also gives the facilitator an idea of where the thought process is and where to go next. Continued role-playing drives students with a feeling of validity and importance. Socratic questioning can be used in drawing out ideas that students may be afraid to vocalize or have not yet connected. The hands-on experience provide a concrete component that will be beneficial as students continue to research. Building the land and creating a landslide will benefit especially those kinesthetic learners.
Assessment:
Student journals should be assessed as far as ability to correlate geologic processes to the change in land in the stream table. Each student will also be accountable for recording a hypothesis, each rain session, and evident geologic processes.
Community Resources:
Contact a local news station and schedule a meteorologist to speak with your class concerning the amount of rainfall monthly and annually for the El Paso area. If they are able to touch upon the amount of rainfall in California as well, it would serve as a great transition for the next lesson.
Content Resources:
Harcourt Science textbook
Bonham Elementary
EPISD
For further information or comments, please contact hclick@utep.edu .