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Use Inquiry in Teaching |
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Counting Birds Count Procedure
Technology Corner
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Introduction Research scientists ask questions and then design experiments to answer those questions. Asking a "good" question, one that can be answered by carrying out experiments, is often quite challenging. Students frequently pose questions that are too vague, making them difficult, even impossible, to answer. These questions can often be modified so they are more specific, allowing students to design a realistic experiment to answer their question. The first step in helping students to develop a good question is to ask students to brainstorm questions they have about birds. We asked 7th grade students to do this, and they created a list of questions. Then we asked the class to think about the questions and to put them into one of two groups: Group L: Look it up. Answer these questions by looking them up in library books or on the Internet. For example, the answer to the question, "Where do Clark’s Nutcrackers live?" is available in field guides. Group E: Experiment. Do your own experiment to answer these questions. For example, the questions, "What do birds eat?" and "What kinds of birds like to live in wetlands?" are questions students can turn into their own research projects by modifying the questions to make them more specific (see below). Creating a specific question from a vague one. We will take a close look at the first question in Group E above, "What do birds eat?" and show how one group of students modified it and designed an experiment to answer the question. In doing this exercise we encouraged students to use their own observations of birds to come up with questions and think about experimental design. Question 1: What do birds eat? This question is too general for students to design an experiment. We told students that we wanted them to modify the question so that they could do an experiment. Because students had trouble at first understanding what we meant by modifying the question, we asked them some leading questions to get them started. Teacher: Our question says "birds." What birds
do we mean? Students already knew that they couldn’t study all birds, so they refined their question to focus on species that they could easily see themselves. Likewise, students knew that different birds eat different foods: a few students knew that American Robins eat worms; other students had observed American Goldfinches eating seeds at the schoolyard feeder. They didn’t want to study all foods that birds might eat; they wanted to find out what certain species eat if given defined choices. They brainstormed a new question that stipulated both the species and the type of food they wanted to study. Question 2: Which seeds do our feeder birds prefer? The class then thought about the word, "prefer." They discussed what is meant by the subjective notion of "preference," and realized that the answer to the question would depend on the choices the birds were given. They wondered if many birds might even prefer a seed not provided in the experiment. As a result, the group decided not to use the word, "prefer" and they refined the question further. Question 3: Which types of seed do our feeder birds eat? With this last question, students would not need to guess about bird preferences; they can determine if birds do or do not eat particular seeds. Several variables, such as type of seed, feeder, how to count birds, are not specified in the question, however, students clarified these issues in their experimental protocol. Experimental Design Once the group agreed on a question, they designed their experiment. Even a question that seems as straight-forward as this one may have many variables that must be considered as the protocol is designed. First the class considered the type of seed they would use. The following types were suggested: black oil sunflower, millet, thistle, mixed, and cracked corn. The group discussed these possibilities and decided to eliminate thistle and mixed seed. Because they had a thistle feeder outside the classroom, they knew that this tiny seed requires special feeders with small holes and wouldn’t be visited by many species. After thinking about mixed seed, they realized that this seed would almost certainly contain the other seeds suggested. If birds ate mixed seed, an observer would have difficulty figuring out if birds were eating an even distribution of all the seeds in the mixture or were eating only specific types of seed. (Note. Students who did not have ideas about what seeds to study could carry out preliminary research at a local seed store to find out what seeds are available. The Classroom FeederWatch website, http://birdsource.org/cfw, also provides reference information about feeders and seeds.) This class decided to offer three seed varieties in their experiment.. They could have chosen just two seed types or could have chosen more types, if they wished. Three choices would be easily manageable. The group then discussed feeder type and placement. They agreed that they should use identical feeders because they did not want a preference for feeder type to influence their data on seed preference. They considered a variety of feeders and chose platform feeders; they had already observed that a greater diversity of species visited this type of feeder than visited any of the others. While some birds seemed to choose other feeder types more often than they chose platform feeders, almost all the species they had observed would eat from these feeders. Several species never used the other feeders that were suggested. Another variable that the group elected to keep constant was the height of the feeders above the ground. A variable they could not keep constant was the precise physical location of each feeder. They, therefore, chose to rotate the seed from one feeder to the other during the course of their experiment. They also thought about how to measure the amount of seed on the platforms and how often to replenish the supply of seed. Because they suspected that different species of birds might show different food preferences, they decided to keep track of the species visiting each feeder. How to count birds was the next issue considered. Should they count every visit to the platform as a different bird, even though a single bird might visit the platform many times; or should they count only the maximum number of each species they saw at the feeder at one time? This issue could be an important one because some birds, such as Mourning Doves often sit on a platform for many minutes and other species, such as Black-capped Chickadees, typically take a seed from the feeder back to the shelter of a tree before eating it. Or, should they keep a record of the species visiting each seed type and then measure the amount of seed eaten after a standard period of observation? These considerations led to a discussion of when and how long they should watch the feeder. They also discussed how often they should make their observations. Students raised questions about the influence of weather, temperature, and time of day. They debated doing the experiment at the same time of day for several days or doing it at different times of day on several days. All of the above considerations could be important when they evaluate their data and draw conclusions. By the end of the discussion, this group of students chose the following protocol: they would place platform feeders five feet above the ground and would observe the feeders for three 10-minute periods each school day for a week. The first observation period would be from 8:00 to 8:10; the next would be from 12:00 to 12:10 and the final period would be from 2:45 to 2:55. They decided to rotate the black oil sunflower seed, millet, and cracked corn every day. Each time a bird hopped onto the feeder would be counted as a single visit. A bird that stayed on the feeder the whole time would be only one visit and a single bird that visited the feeder five times would be five visits; however, they decided to try to note approximately how long individual birds remained on the feeder. They opted to put a cup of seed on the feeder at the beginning of each observation period and to measure the remaining seed after ten minutes. Note that each group of students starting with the question, "What do birds eat?" will probably come up with different questions and will create different experiments. The point of the exercise is to formulate a question students can answer by doing experiments. This exercise is open-ended and has no "right" answer. If the process is successful, the group’s experiment will provide an answer to the question they posed. A student who can master this process is well on the way to becoming an experimental scientist As students become more experienced with a subject, their questions become more interesting and focused. Thus, at the beginning of the school year, before they have watched birds at all, students questions will be very different from the ones they will pose after they have spent time observing birds at schoolyard feeders or elsewhere.
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