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notes - Navodaya Vidyalaya Samiti

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notes - Navodaya Vidyalaya Samitinotes

    Cornell Science Inquiry Partnerships Cornell University http://csip.cornell.edu

    Exploration of Runoff and Infiltration

    Student Experiments with a Homemade Rainmaker

    Teacher’s Guide

    by Bianca Moebius, CSIP Graduate Student Fellow, Cornell University

    and Irka Elsevier, Teacher, Penn Yan High School

    Table of Contents

    Overview ..................................................................................................................... 2

    Subject ........................................................................................................................ 2

    Audience ..................................................................................................................... 2

    Time Required ............................................................................................................. 2 Teaching Schedule ...................................................................................................... 3 Option 1 Full Inquiry Unit, 14 periods .................................................................. 3 Option 2 Basic Inquiry, 5-6 periods ...................................................................... 4

     One-day Introduction to Runoff and Infiltration ..................................... 4 Option 3

    Background: Introduction to Infiltration and Runoff .................................................... 5 Infiltration and Runoff Processes ............................................................................. 5 Human Impacts ....................................................................................................... 5 Learning and Behavioral Objectives ............................................................................ 6 Contextual understanding ........................................................................................ 6 Inquiry and Nature of Science Learning ................................................................... 6 National Science Education Standards addressed ......................................................... 7 Content Standards 9-12 ............................................................................................ 7 Standard 1 Analysis, Inquiry and Design (Grades 6-12): ....................................... 7

    NY State Performance Indicator 1.2......................................................................... 7 Assessment Strategy .................................................................................................... 8 Sample journal/essay assignments ........................................................................... 8 Teaching Tips - Strategy ............................................................................................ 10 Equipment recommended per team for indoor experimental set-up ............................ 11

    Building Sample Containers .................................................................................. 11 Building the Rainmaker ......................................................................................... 11 For conducting an experiment comparing two kinds of soil .................................... 12 Other equipment tips ............................................................................................. 12 Possible Extensions ................................................................................................... 13 Introductory materials ............................................................................................ 13 Outdoor options ..................................................................................................... 13 Wrapping it up ....................................................................................................... 13 Answer Key for Selected Worksheet Questions ......................................................... 14 Worksheet 1. What happens to all that Rain we‟re getting? .................................... 14

    Worksheet 2. Using a Rainmaker to Measure ......................................................... 16 Worksheet 3. Measuring Runoff and Infiltration .................................................... 16 Interesting Links for Background Info: ...................................................................... 17

    Exploration of Runoff and Infiltration

    Student Experiments with a Homemade Rainmaker

    Teacher’s Guide

    by Bianca Moebius, CSIP Graduate Student Fellow, Cornell University

    and Irka Elsevier, Teacher, Penn Yan High School

Overview

    In this unit, students conduct experiments on runoff and infiltration, either in the classroom or outside (in a lawn, field, forest, construction site or path). Students learn about basic soil characteristics while investigating how the processes of runoff and infiltration work, how these processes are influenced by human activity, and how these processes in turn affect the environment. Depending on interest and the amount of time available, your students could use pre-made equipment, or design and build their own. Similarly, students can either carry out pre-determined activities or design their own experiments and research methods. Students can then write up their project and present their research to each other or to other classes.

    Subject

    Earth Science, Environmental Science, Living Environment, Science, Agricultural Science

Audience

Middle School or High School Science

Time Required

    Flexible, depending on time availability and interest: 1 14 class periods of 40-50 min

    each. A 14-day intensive unit is recommended to give students time for true inquiry: to design and conduct their own experiments and develop a deeper understanding of water and soil interactions. Daily journal entries for homework will also help students deepen their understanding and learn to communicate in writing about the subject and about the process of conducting science.

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    Teaching Schedule

    Option 1 Full Inquiry Unit, 14 periods

Day Class Content

    Day 1 Pretest and Journal Assignment, create teams (color coded tests, could do this

    before a break or weekend)

     Homework: Journal Entry observe in several places outside, wherever you are:

    can you see the soil? Is it covered with something? If it were raining right now,

    where would the water be going and what might be affected by the water going

    there.

    Day 2 Teams build rainmakers, by first creating volumetric scales on their rain makers,

    then poking holes with a very thin pins in predetermined arrangement, such as by

    using a wire mesh as a grid. Discussion of importance of precision & accuracy in

    tools/measurements. Either students also build sample containers, or teacher

    provides them.

    Day 3 Introduction: Sponge exercise, demo rainmaker (Worksheets 1 & 2). Share

    ideas/observations from journal entries. Hand out rubric to students and announce

    project. Assign methods reading (Worksheet 2).

     Homework: students read methods and write in journal about what jobs this could

    be divided into on their team

    Day 4 Discussion about what jobs could be, finish rainmakers/sample containers if not

    done yet. Discuss collaborative research/team work in the real world, and how

    what they will be doing connects. Let students know they will present their

    research findings at a conference in the end. Encourage students to “talk science”

    to each other, as this will help them do their final project.

    Day 5 Students set up and conduct one practice run, all with same soil and practice

    operating their rainmakers and catching/measuring runoff as a team. Class

    discussion on important pieces of methods, issues, problems, etc. Those who are

    done early can collaboratively figure out calculations.

     Homework: what sources of error were there in your first measurements today?

    Can any be prevented? What worked? What went wrong? How will you fix this

    for your experiment?

    Day 6 Brainstorm what is in soil, and soil issues related to runoff/infiltration. Students

    then rotate through about a dozen different soil materials to make observations to

    help students visualize and decide on questions/hypotheses. In teams, students

    pick questions, write hypotheses, and start their research plans. Teacher collects

    plans to provide feedback.

     Homework: Journal entry how is your life affected when water runs off give

    some examples… do you think runoff is endangering anything in your

    neighborhood? AND/ORFree write about anything that is confusing to you

    about the methods, about infiltration and runoff, or anything else related to this

    project

    Day 7 Teams finish writing their research plans, incorporating written and/or verbal

    feedback from teacher. Discussion about importance of replication here, and any

    other relevant pieces that the class could benefit from.

    Day 8 Teams set up their experiments and make their first sets of measurements (3

    replications for each sample should be done)

     Homework: what sources of error were there in your measurements today? Can

    any be prevented? What worked? What went wrong?

    Day 9 Teams finish their measurements, and start calculating total runoff, total

    infiltration, %‟s, averages, etc, if there is time.

     Homework: finish calculations, and draw bar graphs

    Day 10 Students finish/fix calculations and bar graphs in teams, then analyze their data,

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    guided by worksheet, first individually, then sharing answers amongst team

    members. Teacher discusses final project & rubric, and that students will be

    reviewing each others work tomorrow before the final project is “published” at the

    conference several days later, just like real scientists.

     Homework: write a first draft of text for Final Project

    Day 11 Students peer review each others‟ work, give each other feedback using the rubric.

    Teacher collects student feedback forms and student drafts and provides feedback.

    Day 12 Allow a full class or parts of class time for several days for students to work on

    final projects

     Homework: students finish projects

    Day 13 Short discussion of the role of conferences in science. Classroom conference.

    Day 14 Post-test

Option 2 Basic Inquiry, 5-6 periods

    Day Class Content

    Day 1 Short introduction, see above. Students are divided into research groups of 3-4

    students, either by the teacher or randomly. Teacher demonstrates how to use an

    indoor set-up to measure runoff (see Student Worksheets 1 & 2)

    Day 2 Designing the experiment: The teacher may leave the question wide open, may

    give students any number of options to choose from, or may assign the question to

    each group, depending on materials available. The teacher may want to lay out a

    number of soil materials to look at (sand vs clay, soil with grass vs bare soil, etc),

    so that students have some visual information to help them in designing their

    experiment. If applicable, students meet in groups to decide on the question they

    wish to investigate. Students make predictions about the amounts of runoff they

    will get from two different soils.

     Students are sent home with the homework to read the methods (Worksheet 2) for

    making these measurements.

    Day 3 and Lab Students are given/choose their jobs within their group for laboratory

    period measurement. They reread the methods, and class discussion reviews what

    everyone‟s job will be. With suggestions from the teacher, students set up their

    experiment with two different soils. Students measure runoff and infiltration once

    on each of their two soils as a team. They collaborate to figure out how to

    calculate total rainfall, runoff and infiltration for each soil (see Worksheet 3).

    They are sent home with the homework to finish their calculations.

    Days 4 and 5 In their groups, students check their calculations, and summarize them in a table,

    draw bar graphs of their findings, compare results to their hypotheses, and explain

    their results (see Worksheet 4). Group work is followed by open class discussion

    of what each research team found (groups can give informal 5 min presentations),

    explanations of findings, and implications for the environment. Possibly expanded

    discussion on how experimental design might be improved, or what future

    experiments students might do to find out more about their topics.

Option 3 One-day Introduction to Runoff and Infiltration

    The period starts with an introductory mini-lecture/slide show (10-15 min), with interactive, authentic questions, asking students to relate the processes discussed to their prior knowledge and daily activities and

    experiences. This lecture introduces runoff and infiltration as parts of the water cycle, and emphasizes the

    importance in our lives. The teacher may use a mind-map to summarize student contributions on the board. Lecture is followed by a laboratory activity using sponges to illustrate runoff from and infiltration into soil.

    (See Student Worksheet 1.)

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Background: Introduction to Infiltration and Runoff

    When it rains, the water needs to go somewhere but where does it go? What affects

    where it goes? And how does the water‟s path directly affect our lives? When rainwater

    hits a permeable, or porous, surface (such as soil or fill material) part of the total volume of water will infiltrate, or move into the soil from the surface through the soil‟s pores. The

    remaining water will run off, or move down-slope along the surface. Our drinking water,

    the food we eat, a farmer‟s salary, flood disasters, pollution of streams, rivers and

    groundwater, wet basements, our backyard garden, urban construction sites, and whether we can play baseball outside after it rains all of these are directly affected by the

    processes of infiltration and runoff, and thus could be material for lively class discussion.

Infiltration and Runoff Processes

    During infiltration, the soil acts much like a sponge. It soaks up as much of the water as it can. Some of the infiltrating water is stored in the soil, where it can be used by plants and other inhabitants of the soil, and some seeps down through soil until it reaches the groundwater. Groundwater may be stored for long periods of time. As groundwater slowly seeps downhill underground, it also fills streams and lakes from below.

    Both, the rate or speed at which the rain is falling, and the type of surface it hits, will affect how much of the rain infiltrates. When rain comes down faster, there will be more runoff, because the soil can only soak up a certain amount of water per unit time. (Too much rain too fast can cause a flood!) For a given soil, infiltration is slowest when the soil is already saturated, because the pores are already full. It is also slowest when it is made of the smallest particles (clay).

    Numerous characteristics of a surface control how much of the total water will infiltrate. For example, fine textured soils (made out of smaller particles: more silt and especially more clay) have smaller pores than coarse textured soils (made out of larger particles: more sand). Therefore infiltration will be slower in fine textures than in coarse textures. Clay particles can be so small, flat and densely packed, that they form an almost impermeable layer, so that very little infiltration can happen.

    Well structured soils have larger and more continuous pores, often from old worm channels or from where roots used to be, and therefore these allow for more infiltration than soils with degraded structure. Structure degrades, for example, in soils that are compacted from construction, foot- or vehicle-traffic, or by agricultural machines, and in soils that don‟t have enough plants growing in them. More water will infiltrate on a soil

    covered by vegetation than on bare soil of the same type, because the vegetation slows down water flow, provides easier entry points for water into the soil along stems to the roots, and because they create a more irregular surface, where small pools can form and then infiltrate. Less infiltration will occur or on a very smooth surface than on a pitted, irregular surface. Less infiltration will occur on a steep slope, than on a shallower slope.

Human Impacts

    In urban settings usually much of the surface is paved or built on. These surfaces become impermeable, thus leaving very little space for water to infiltrate. This causes a lot of runoff, which can pick up pollutants from its quick trip across roads, parking lots and roofs and carry them into streams. Less infiltration also means decreased groundwater

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    recharge. (Infiltrating water moves down through the soil until it reaches and replenishes the groundwater). Wetlands can act as sponges, because they are often at the bottom of slopes, where they catch runoff and hold this water in place until it can infiltrate. Because many former wetlands have been filled in and built on, urban runoff instead quickly enters streams, causing sudden changes in the amount and quality of the water in the stream. During heavy rains, the large amounts of water that must run off can cause floods.

    In agricultural settings, where the bare soil allows for less infiltration, runoff often carries sediments into surface waters. Both infiltration and runoff water may carry fertilizers and pesticides from agricultural land, or toxic chemicals from industry and other urban activities into surface- and groundwater.

Learning and Behavioral Objectives

    After a more extensive unit, including an inquiry project, students will also be able to:

Contextual understanding

    1. define runoff and infiltration in their own words and explain the difference between

    them

    2. identify groundwater as one of the places where infiltrated water goes 3. identify surface waters (lakes, streams or rivers) as some of the places where runoff

    goes

    4. draw connections between runoff and infiltration and their own lives/world events, and

    between runoff and infiltration and previous units in class discussions (verbally and in

    writing in their journal entries and final project).

    5. name at least three characteristics of soils that affect whether more or less infiltration

    will occur, and explain why these characteristics cause differences in infiltration 6. state some impacts of human development (such as roads, buildings, filling wetlands,

    compacting soils, road cuts, etc) on infiltration and runoff

    7. list some environmental impacts of increased runoff

    8. define the difference between observations and inferences

Inquiry and Nature of Science Learning

    9. state a hypothesis to test with an experiment, make a prediction regarding percentages

    of runoff vs. infiltration in soils to be tested, and explain their reasons for this

    prediction.

    10. collaborate with a team of peers and the teacher to pick a variable to examine and

    design an experiment

    11. collaborate with a team to gather infiltration and runoff data

    12. make calculations of percent runoff vs. infiltration and graph their results 13. explain results and make inferences about real-world effects, using experimental

    observations on soils, and conceptual understanding about soil characteristics and the

    impacts of those characteristics on runoff and infiltration

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National Science Education Standards addressed

Content Standards 9-12

    A. Science as Inquiry

    ; Identify questions and concepts that guide scientific investigations

    ; Design and Conduct Scientific Investigation

    ; Use technology and mathematics to improve investigations and communications

    ; Formulate and revise scientific explanations using logic and evidence

    ; Communicate and defend a scientific argument

    F. Science in Personal and Social Perspectives

    ; Natural and human-induced hazards

Standard 1 Analysis, Inquiry and Design (Grades 6-12):

    Mathematical Analysis:

    ; Key Idea 2: Deductive and inductive reasoning are used to reach mathematical

    conclusions.

    ; Key Idea 3: Critical thinking skills are used in the solution of mathematical

    problems.

    Scientific Inquiry:

    ; Key Idea 1: The central purpose of scientific inquiry is to develop explanations

    of natural phenomena in a continuing, creative process.

    ; Key Idea 2: Beyond the use of reasoning and consensus, scientific inquiry

    involves the testing of proposed explanations involving the use of conventional

    techniques and procedures and usually requiring considerable ingenuity.

    ; Key Idea 3: The observations made while testing proposed explanations, when

    analyzed using conventional and invented methods, provide new insights into

    phenomena.

NY State Performance Indicator 1.2

    1.2 g. Earth has continuously been recycling water since the outgassing of water early in its history. This constant recirculation of water at and near Earth‟s surface is described by the hydrologic (water) cycle.

    ; Water is returned from the atmosphere to Earth‟s surface by precipitation… A

    portion of the precipitation becomes runoff over the land or infiltrates into the

    ground to become stored in the soil or groundwater below the water table. Soil

    capillarity influences these processes

    ; The amount of precipitation that seeps into the ground or runs off is influenced by

    climate, slope of the land, soil, rock type, vegetation, land use, and degree of

    saturation

    ; Porosity, permeability, and water retention affect runoff and infiltration

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Assessment Strategy

    Informal assessment can be done by watching (and taking observation notes on) student progress in the classroom. The included worksheets provide a more formal assessment. Worksheets will guide students to develop a question and a hypothesis or prediction, design their experiment, record data and relevant observations, create graphs of collected data, and explain and interpret findings. A final creative project can be used to allow students to individually synthesize and demonstrate their understanding.

    It has been shown that students‟ writing is of higher quality when they write for an authentic or relevant audience that is taking interest in the content, as compared to when writing for the teacher who is generally perceived to merely judge the quality of a student‟s

    work. Therefore time should be made for a day of peer-review, before students hand in their final project. Final projects could then be published in a classroom science journal that is available to other students. Journal entries and/or 5 min essays can be used to start or conclude lessons throughout the unit. Students may alternatively (or in addition) be assigned homework journal entries, especially for a longer unit, in which they are encouraged to explore questions, confusions, scientific reasoning and their life connections to the content matter. One way to motivate students to write thoughtfully may be to tell them that they will be reading each other‟s journals.

Sample journal/essay assignments

Activating Prior Knowledge:

    1. Write a list, or draw a concept map showing how soil is related to parts of your life. 2. (Have students sit outside to write this one for homework.) If it were raining right now,

    where would the water be going, what would be influenced by it and how?

Mid-unit:

    3. If more water runs off, how could this affect parts of your life?

    4. What‟s confusing to you about runoff and infiltration? Why?

    5. What did you learn? Did you have new thoughts about last night‟s journal entry after

    participating in today‟s class – what are they?

    6. Do you think runoff is endangering anything in your neighborhood, if so, what and how?

After Reading Methods:

    7. What confuses you about the methods reading is anything not clear, if so, what?

    8. Are there any words you do not know in the description, if so, which ones? 9. What questions do you have about the method?

    10. Why do you think it could be useful for you to know when you do and do not

    understand something? How or for what else do you think you could use this awareness?

After Experimental Work in Lab:

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    1. What sources of error were there in your measurements today? Can any be prevented?

    What worked? What went wrong? How will you fix this for your experiment/for a

    future experiment?

    2. What about your team‟s collaboration worked well? What didn‟t work well? How

    would you fix it? How do you think such team work relates to the work of professional

    scientists?

After Finishing Experiment:

    11. Free write about anything that is confusing to you about the methods, about infiltration

    and runoff, or anything else related to this project

    12. Draw a diagram including precipitation, runoff and infiltration, showing why you found

    more infiltration on one type of soil than the other.

    13. Write a letter to explain to an interested friend or family member what you found out in

    your experiment and why you think this happened.

    14. Here‟s a fun one: Imagine you are the soil. Write a letter from the perspective of the

    soil, telling a land manager/farmer/contractor/road construction crew what you are

    being put through.

    15. What did you learn about science, about runoff and infiltration or about team work

    from members of your team or from other classmates?

    16. Do your data make you wonder about something? Why? How? List at least 3 related

    questions.

    17. If you were to design another experiment that‟s related to runoff and infiltration, what

    would you do?

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    Teaching Tips - Strategy

    ; Probe for students‟ thoughts and observations frequently throughout the unit and

    guide their thinking to valid applications in/connections to the real world. They

    should discover not only ideas about the content, but also should learn to value their

    own ideas and those of their class mates. This can happen by modeling to them that

    everyone has interesting contributions, by asking authentic questions (to which

    there are multiple answers) rather than test-questions (to which there is only one

    answer). It is also essential to follow up on student answers, and allow students‟

    ideas to influence the direction of class discussion.

    ; Encourage students to use each other as resources and to share ideas during

    observations and data analysis. Group collaboration and communication of

    scientific ideas can be a significant lesson in this project.

    ; To improve group collaboration during measurement, guide teams to assign to each

    group member particular tasks that are their responsibility (i.e. data-recorder, time-

    keeper, runoff-measurer, rainmaker control person as in Worksheet 2.). Groups of

    3-4 students are best. After students have read the methods, you may want to lead a

    discussion that helps students plan which tasks need to be performed instead of

    giving them the list of jobs on Worksheet 2.

    ; Encourage students to explore their own thoughts about the experiment, by making

    sure that the emphasis is more on exploring ideas, and explaining how/why they are

    arriving at their answers, and less on “being right.”

    ; You may leave students some time for reading each other‟s journal entries, and

    asking each other questions about each others thoughts.

    ; You may, if you have the time, have students do “dialogue journals” with you

    (and/or with other students) i.e. you will collect some of the journals each day and

    make your own entries, carrying on conversations about the subject matter with

    students, by expressing appreciation, curiosity and interest in their thoughts, asking

    for clarification, or asking them further questions.

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