Land and Water
Lesson 3
Modeling Rain on Land
Students will use the water/land model to investigate what happens to the Earth's surface when it rains. Student will discuss a "fair test" in order to compare one team’s model results to another team’s model results.
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.
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 discuss what a "fair test" is and how procedures need to be followed consistently.
- Students will observe and record the effect of "rain" on the water/land model.
- Students will use their observations to figure out about rainwater flowing on the land and how streams are made.
3. Lesson set up and Management
Materials:
- Squeezing the bottle while making it "rain" can cause the sprinkler head to come off and the water in the bottle to gush out.
- Make sure that the student holding the catch bucket is paying attention and holding the bucket close to the hole in the bottom of the clear plastic box.
- Scrapers & sprinkler heads break, caution the students to be careful. Encourage them to move just small amounts of dirt. Also, having an alternative or a few spares can make the class run more smoothly.
- Throughout the unit, a student group may end up with mud; make sure that the stream table has time to dry out (become less muddy) before Lesson 4. OR you can add additional earth materials to change the consistency from mud to workable soil.
Student Management:
- Have students take turns doing the various set-up steps in Procedure 5. Number the students in each team 1-4. Have student #1 set-up the absorbent pads. Have student #2 place the box on top of the pad and push in the rubber stopper, etc.
- Procedure 6, discuss "fair test" with the class. When the students look at the other models in the room (Procedure 10) it may be another opportunity to discuss "fair test" as students compare the observations of their model to the other models. Could the differences in the results be due to differences resulting in an "unfair test?"
- Preconception: Make sure students understand the difference between weathering and erosion. Weathering is when rocks and materials are broken down and erosion is when materials are moved from place to place. Students frequently think that weathering means that weather caused the material to move. Unless there is a big chuck of packed sand that breaks down into little sand pieces, there is little weathering occurring in this model.
- Procedure 3 the word, "hypothesize" is used in a way that is inconsistent with the Washington GLEs. Step 3 is very important. I would just ask the question, "In this Land and Water model, what would the sprinkler head be modeling?" This question would be more consistent with students understanding a model and, also, wouldn't confuse them with multiple meanings of the word "hypothesize."
- Extensions 3 could be used as an opportunity to have the students practice the investigative process (GLE 2.1.2). The investigative question could be, "What is the affect of different earth materials (rock or soil) on the how the surface of the soil is changed when it rains?"
Writing Support:
- Science notebook: Procedure 3, instead of just hypothesizing about what the sprinkler head could model, have the students draw a labeled diagram in their science notebook, labeling the parts of the system/model. Then have them label what each part is modeling. Example: sprinkler head = rain, dirt = Earth’s surface, water in the bottle = rain drops in a cloud.