Do It Yourself First: Leading Student-Directed Inquiry

by Jim Martin
CLEARING guest writer

f you’ve never taken your elementary, middle, or secondary students out of the classroom to learn, and can’t find a helpful mentor or workshop, it’s okay to learn to use the real world to generate curricula and teach for understanding rather than to pass tests just by doing it. Just make a plan and stick to it, and you’ll be okay. Try a place on your school grounds first, then move to a place in the community when you’re comfy.

There is a simple way to do a student-directed inquiry outside your classroom, involving observations on invertebrates. You can use it to discover whether this kind of work is comfortable for you to do, and if it generates curricular content that satisfies your anxieties about meeting mandated standards and benchmarks. You can start it on your school grounds, or if you’re not comfortable with that, right in your classroom. The only caveat is that you have to let your students think and ask questions, and follow the parts of the project that capture their interest. That is, after you’ve first guided them (and yourself) through the process.

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The nice thing about the project we’ll be describing is that it begins with you facilitating a guided inquiry. It doesn’t matter what grade level you teach, the basic work applies to all of them. The vocabulary and complexity of conceptual content will vary with grade level and student experience, but the basics apply to all levels. The plan is this: We’ll make a small compost heap, then see what comes to live in it. Then we’ll have our students do the same. Simple, but loaded with potential.

First, do your own inservice, perhaps this summer. Start the compost in your own yard or somewhere on the school grounds as your source. Don’t place it where it will always be in direct sunlight, since it needs to stay moist. Put about 5-10 gallons worth of different kinds of plant material in it and turn it once a week with gloved (or ungloved) hands. Keep it moist, but not wet. It’s necessary to start outdoors to attract the invertebrates and microbes which will populate your students’ compost ‘piles.’ As you tend your compost heap, notice what is living there. (If you’ve already done this, I’ll bet you’ve gone to a book or the web about what you’ve found. That’s your brain doing what it’s designed to do.)

As you do your work, try out some learning activities. What is the temperature at the surface of the heap, and in its depths? How do you go about measuring the temperatures? Any glitches? Ask yourself how any temperature differences might have come to be. If it’s not directly explainable to you, who might you ask to find out? (This is a skill we all have to develop when we move out into the real world.) What mathematics activities can you use to make sense of the temperature data? What tells you more, the numbers themselves, or their graph, average, median, range? Would the data be different if the compost heap was larger or smaller? Let’s look at more of the things we can learn.

After your compost heap has been working awhile, you should be finding an increase in the numbers of invertebrates living there. If this isn’t the case, go to places where plant material is obviously decaying and bring samples back to your heap. Keep a record of how many species you find in your heap as you turn it, and how many of each you observe. This means you’ll have to be systematic about how you turn the heap. And about how you record the information you measure, count, and observe. You can pass these skills and understandings on to your students.

As you count species and their numbers, use that data to track species diversity in your compost heap. As a rule of thumb, the greater the species diversity, the healthier the system. Whether you work with kindergartners or high school seniors, you’ll need to know something about species diversity. You can google the term, find some sites which explain it in a way you can understand, and which detail some of the math used to make sense of the numbers. Here’s one you can use; a little esoteric at first glance, but ultimately doable; Simpson’s Index, D = Σ ni(ni-1)/ N(N-1), where D is Simpson’s Diversity Index, Σ stands for ‘the Sum of,’ ni is the number of organisms you counted in the ith species (so the number of organisms in the 3rd species you counted would be n3, and i goes from 1 to the total number of species you counted), and N is the total number of individuals counted among all species. This means that you take the sum of the numbers you get from multiplying the number you counted in each species times that number minus 1, then divide that sum by the total number of individuals you counted times that number minus 1.

Try it for 3 species: Species A, with 10 individuals; Species B, with 5 individuals; and Species C, with 20 individuals. The first ni set is 10(9), the second is 5(4), and the third 20(19), which totals to 490. There are 35 individuals all together, so the denominator is 35(34) = 890. Dividing 490 by 890 gives you about 0.56. What if the counts were 23, 51, and 36? Your numerator and denominator should be 4,316/11,990. If this is confusing, say so in a comment below, and I’ll get back to you with more details.

Sounds complicated, but by the time you’ve done three or four sets of species, you’ll get it down. Just be sure that you sum all the individual counts times themselves minus 1 before you divide by the total counted times the total counted minus 1. The answer to all this, D, gives you a number you can compare with other counts you or your students make. Remember, the reason you need to try this diversity calculation is to get an idea of one way that diversity is described. With your students, you can just use the total number of species present to stand for the same thing. This is the simplest math which can be used to estimate species diversity, the total number of species, a number students can use to compare the number of species in different compost heaps, and which may correlate with other measures of diversity.

There is a spectrum of ways to name diversity: number of species, species richness, species evenness, or a calculation like Simpson’s Index. None do a perfect job, since diversity is a dynamic with many aspects. For now, you can only choose one and use it consistently until you have good reason to use another statistic. We’ll take another look at this in the next blog.

Use your counts of living things to graph a population curve. Choose one species and plot it with time on the x-axis, and number of individuals on the y-axis. This is a population growth curve, and they are an indirect way of determining how an environment treats a particular species residing within it. In setting up your compost heap, you’ve created a new environment, and populations living within it should increase during the initial exploitation phase. Soon enough, those curves will change, raising nice inquiry questions.

Use the heap itself for learning. How big is it? Is it always that big? Bigness can be derived from measurements that students make. How tall is it? How wide? How long? How can you determine its volume? Do any of those numbers correlate with the range of temperatures in the different compost heaps? Species diversity? Population curves? Temperature range and diversity?

What about the biology of the organisms living in the heaps? If you’re up to it, you can take a piece of liver, blend it with a little water or electrolyte like pedialyte, then introduce a drop of this to a container with 250 ml or more of hydrogen peroxide (H2O2 ). Take the temperature of the hydrogen peroxide before adding the liver extract, then periodically during the next 20 minutes. As simple carbohydrates are metabolized to produce useable energy in the form of ATP in nearly all organisms from microbes to Homo sapiens, the extra oxygen atom in one of the intermediary products, hydrogen peroxide, is released leaving water (H2O), an oxygen atom (O), and the energy which held the oxygen atom in place. That energy isn’t re-used, and goes off as heat. Compare the results of this experiment with your data on population and temperature. Is there something to be learned? Might your students understand the basics of what they observed?

What can you find out about four of the species in your compost that explains how they are able to live there? The organisms you find are living in a dynamic relationship which keeps the entire community alive, an economy which cycles materials and moves energy in a productive way. Can you build some elements of a food web from the information you have? What else can you find out about the biology and ecology of compost heaps?

If you teach or use language arts, how can you use the compost heap and its components as metaphors to drive a piece of writing? A piece of art? Music? If you teach science, and have never used these arts and humanities deliveries, try one. You might be surprised at what you’ll learn. I certainly have been.
When you’ve studied your compost heap long enough to feel comfortable with it, have your students learn some thing about them. Use the piece you have the best handle on. The first time through the process with your students, you demonstrate each step. Let students ask questions or make observations as you feel comfortable. You can use your own compost, and demonstrate how to turn it to expose the invertebrates living there. (If you’re up to it, you can find out how to plate out microbes that will be living there, and find out what they do and who eats them.)

When you’re ready for your students to do theirs, have each group start compost heaps somewhere in the schoolgrounds, one 5 gallons in size for each group of four or five students. You can also have students bring in their own mulch, etc., or place boards on the ground at home then collect what’s living on and under them including any molds they find. You might suggest they place the animals in a jar of moist compost, keeping the lid slightly ajar for air, and simply bring the board in and set in in their compost heap. Once compost heaps are doing well (outside the building), you can make ‘sand traps’ by filling plastic bucket lids with a layer of sand and placing them next to a compost heap. Any small mammals or birds who are attracted to the compost will leave footprints in the sand. These don’t always work, but are pretty neat when they do. This will raise questions they can begin to answer.

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This is the twenty third installment of “Teaching in the Environment,” a regular feature by CLEARING “master teacher” Jim Martin that explores how environmental educators can help classroom teachers get away from the pressure to teach to the standardized tests, and how teachers can gain the confidence to go into the world outside of their classrooms for a substantial piece of their curricula. See the other installments here, or search Categories for “Jim Martin.”