- Why is it cold in winter?
- What happens if you leave the salt out of the chocolate cookie recipe?
- How do giant cruise ships stay afloat?
- Do fish prefer real worms or fake ones?
In science class, students always seem to have more questions than teachers can answer. Before answering any more questions, perhaps we should pause and ask ourselves if we should answer them. The National Science Education Standards (National Research Council 1995) recommends that instead of imparting knowledge, our role is to help students develop the skills, values, and attitudes that facilitate a scientific understanding of the natural world. "Inquiry into authentic questions generated from student experiences is the central strategy for teaching science," the Standards states.
The first questions teachers may have are (1) How do we involve students in asking questions? and (2) What do we do after they ask them?
The idea that questioning strategies are a key attribute of inquiry-based teaching (Rowe 1978) is not new. But historically, either the teacher initiated the questions, or the teacher or students recited them from a textbook. In either case, the student's job was to provide the "right" answers. Fortunately, educators have begun to think of teachers and students as members of a community of learners (Moll and Whitmore 1993). As such, the class learns through a balance of teacher and student questions.
The Soap Question: Balancing Teacher-Directed Inquiry
Effective classroom questions promote relevance, encourage ownership, help students interpret their observations, and link new learning to what students already know.
In our middle school classes, we have discovered that students ask questions that often directly relate to the goals and objectives we have established. By integrating their questions with the activities we have planned, we can reinforce learning in the limited time we have. For example, during a unit on density, students' questions helped us make the transition from teacher-directed to student-directed learning. Together, we dispelled many misconceptions about this concept (such as that heavy things sink).
Before planning the unit, we wanted to find out what students already knew and what they were interested in learning. We enlisted Ogle's (1986) teaching strategy, whereby students connect their prior knowledge with new learning within an organized framework—a "K-W-L" chart (Know—Want to Know—Learned).
One student asked, "Why does Ivory soap float and other soaps sink?" The question initiated a class discussion, during which other students acknowledged that they, too, had wondered about this. Students suggested a range of explanations—Ivory is lighter, Ivory has more air, colored soaps are heavier because they have more dye, and "It must have something to do with what the soap is made from." The soap question, which students related to their real-world experience, was a perfect extension to the investigations we were considering. As a class, we began filling out a K-W-L chart on sinking and floating.
The Density Question: Building a Conceptual Foundation
We decided to help students construct a conceptual foundation about density and then use the soap question to reinforce and extend the concept. Students began by investigating how a variety of common objects, such as balloons, plastic utensils, rubberbands, and crayons, act in water.
As cooperative groups, students determined the mass and volume of each object and identified the relationship between the two. We then introduced the equation d = m/V (density equals mass divided by volume), enabling the students to use their data to determine whether each object was a sinker or a floater. Throughout this activity, we asked a variety of questions to help students interpret their observations and data. We had planned our questioning strategies in advance to make sure we asked a range of high- and low-level questions. We began with attention-focusing questions (Elstgeest 1985) to help students develop a knowledge base. This would enable the students to apply what they learned through low-level questions to answering higher-level questions. We then asked them to consider both qualitative and quantitative observations to help them respond to comparison questions and order their data.
Sinkers or Floaters? Applying What's Learned
- Which objects were sinkers? Floaters?
- Which objects have greater mass than volume?
- Look at all the sinkers. What can you tell me about the relationship of mass to volume?
- How are all the floaters alike? How are all the sinkers alike?
- What do you now know about objects that sink? Float?
- What do you think will happen to the results if more mass is added to each object? How do you know? How can you find out?
At our next hands-on session, we returned to the K-W-L chart and revisited the soap question. This time, we asked, "Using what we have learned about density, what explanations can you now offer?" Some students immediately applied what they had learned, responding that the mass of the bar of Ivory was less than its volume. Others said the density of the bar of Ivory soap must be less than one, and some students were not yet ready to offer an explanation. Accordingly, our next question was, "How can we find out?" This laid the groundwork for students to take an active role in planning the investigation process.
How Can We Find Out? Investigating
The class broke into small groups, each of which discussed the question and proposed a plan. We then reassembled to consider each group's plan and select one to implement. (Alternatively, each group could have tried its own plan and then compared results.)
The procedures were similar to those we modeled in the earlier lab, except this time students were more attentive to details. Apparently they had discovered that a slight irregularity in measurement could skew the results. They also appeared to have developed a great deal of ownership of the soap question and were highly motivated to come up with the right explanation.
The students wanted to test as many brands of soap as possible and they brought in more than we needed. Before proceeding, each student wrote a hypothesis and set up a data table. During the investigation, we observed students at work and asked spontaneous questions, such as: "What do you notice about the float line?" and "How does bar X compare to bar Y?"
Why Do the Grapes Sink? Generalizing Learning
- As you use a bar of soap, how does this affect its density?
- You are canoeing on the river and your canoe tips over. The grapes and a film can with film in it sink, but the apple and an empty film can remain afloat. How do you explain this? (For this question, we displayed a tank with the four items.)
Student responses helped us assess what they learned so we could decide how to proceed.
Unlike the Ivory soap question, not all questions students ask are appropriate for hands-on classroom investigations. For example, while brainstorming what they wanted to find out about sinking and floating, some students asked interesting, research-oriented questions, such as, "Why does ice float?" "Why do dead fish float?" and "Will lead float?"
If we are to emphasize hands-on/minds-on learning, we must recognize that research is a valid and critical aspect of scientific inquiry. Observations, rather than laying to rest a question, may promote related questions that cannot be answered through sensory experiences alone (Matthews 1992). Students need to gain familiarity with accepted research that has gone through the validation process (National Research Council 1995). For this reason, we help our middle school students acquire the skills necessary to pursue their research questions.
Why Do Dead Fish Float? Minilessons and Research
To teach research skills, we use the minilesson—an approach we borrowed from Calkins and Nancie Atwell (Atwell 1987). Our first minilesson usually focuses on classifying and clarifying student questions.
Our goal is for students to be able to sort their questions into two groups: those we can safely investigate in the classroom with readily available materials and those that require research as a primary approach because of safety requirements and materials needed. If the class does not reach a consensus on a question, we facilitate a peer debate and let the students attempt to convince one another.
Once students determine which questions have a research focus, we lead a set of minilessons that address the question, "How can you find out?" Through examples, we discuss how to select the resources that are most appropriate for a particular task.
For example, when we asked students how they would begin to research the question, "Why do dead fish float?" they began with experts. They said they could ask a science teacher or someone who works at a fish store, although they might learn more from an ichthyologist. Of course, we then explored how to find an ichthyologist. We also introduced them to a variety of other resources, including trade books, encyclopedias, almanacs, the Internet, and videotapes.
With limited class time, it is difficult to have all students address all the questions. We have learned that a more practical approach is to ask each group to become an expert on one question. Or two or more groups may research the same question and then compare their resources and results. This again reinforces the idea of establishing validity.
I Was Surprised to Learn That: Holding a Miniconference
Next, as a class, we plan a miniresearch conference. Members of each group present their research and students ask other groups specific questions. We sometimes formalize the questioning procedure. We may distribute index cards before the conference and ask each student to write a follow-up question for another group. After each presentation, the student-researchers collect and respond to the questions.
Another strategy is to have students fold a sheet of paper into four sections and respond to the presentation by writing down questions they still have and information they appreciated learning about. They then hand over their responses to the presenters. For example, the responses might begin with the phrases "I was surprised to learn...," "I liked the way...," "This picture represents...," and "Questions I still have...."
This process of investigating research questions and sharing data allows us to learn about a variety of questions in a limited amount of time. It also reinforces the idea that we are a community of learners.
Even with creative approaches, we will never teach all there is to know about science. But as partners in the learning process, we can help students acquire the scientific skills and habits of mind that lead to understanding (Rutherford and Ahlgren 1990). We can also stimulate their appetite for explanation and encourage their sense of wonder.
