In a recent Education Week article, a study by David Klahr, a psychology professor at Carnegie Mellon University, and Milena Nigam from the University of Pittsburgh finds that "students taught through direct instruction were more likely on average to become 'experts' in designing scientific experiments than those taught through discovery learning."

Unfortunately, some will conclude that direct instruction is the best way to teach science. Please read on before making any conclusion about this research.

As scientists and science teachers, we have to ask ourselves: What does the evidence say? How should these research findings inform classroom practice? And most importantly, what is meant by the terms used? According to the NSTA Press® publication The Lingo of Learning (NSTA 2003), direct instruction results in the teacher (who is the expert) passing knowledge directly to students. The student role is a passive one, and the lecture delivery mode is often equated with direct instruction.

One of the research hypotheses was that "direct instruction will be more effective than discovery learning in the acquisition of ‘control of variables strategies' procedures." What the results actually show was that students who were taught how to design experiments and control variables learned better (77%) than students who were asked to conduct open-ended inquiries (23%) without teacher guidance.

The evidence showed that when the teachers provided "direct instruction" to teach students an experimental design process, students were able to control variables more successfully than students who were asked to do discovery on their own. As any elementary science teacher knows, scaffolding the learning for students supports their understanding and ability to conduct experiments. In essence, students are provided with a guided inquiry approach. But the researchers concluded that "Direct Instruction was clearly superior to Discovery Learning in children's acquisition of control of variables strategies."  

So what can we learn from this research? Teachers must teach students an experimental design process before students can be asked to conduct their own experiments when studying science concepts. Even though this study was conducted with third and fourth graders, it's reasonable to expect that the same could apply to secondary and even college students: Teaching an experimental design process often occurs using an exploratory experiment or using direct instruction, but the teacher should guide the process.

The publicity given to Klahr's and Nigam's study is prompting many to ask, "What is the best way to teach science?" The answer is that effective science teaching includes exploring and explaining in addition to various other effective strategies. Research tells us that an inquiry-based approach promotes a deep, comprehensive understanding of science; research also tells us that some data and facts can be taught more efficiently through direct explanations. The challenge is that we need to learn more about the proper balance of all the teaching approaches as they relate to the science classroom.

Research conducted by Horizon Research, Inc., and reported in Looking Inside the Classroom (Weiss et al. 2003) provides some important insights into designing high-quality lessons, which then helps inform teachers about effective teaching. (The complete report is available online at www.horizon-research.com). From their observations of mathematics and science classrooms, trained observers identified components of high-quality lessons and used their observations to rate the lessons.

The report concluded that students need to be engaged with important science ideas and concepts. In the classrooms observed for the study, it didn't matter which teaching strategy was used. What did matter was student engagement. Providing demonstrations and investigations greatly increases the level of student engagement. Also, investigative strategies encourage collaboration among students.

The report also concluded that the content needs to be rigorous and provide a depth of understanding that presents the science learning as part of a dynamic body of knowledge. The content taught must be accurate, significant, and worthwhile. Direct instruction is a typical strategy that supports learning of key vocabulary and factual content information. Inquiry-based instructional strategies lead to student investigations that can in turn lead to greater conceptual understanding. Direct instruction alone cannot replace the in-depth experience with science concepts that inquiry-based strategies provide. Students must create mental models that connect their learning experiences to the science concepts. Learning cycles that allow students to explore a concept in-depth support students' sense-making of their observations.

Many misconceptions and myths exist about what many educational terms actually mean. One myth, for example, is that all science should be taught using inquiry-based strategies that expect students to construct their own knowledge. One can and should choose from an entire spectrum of inquiry-based strategies that range from guided inquiries to open-ended, student-designed experiments. Similar myths exist for direct instruction.

If the goal is student understanding, then teachers have to understand how students learn. The book How People Learn (National Research Council 2000) contains implications for science teaching. Teachers must access a student's prior knowledge. Content must be taught in context and relate to a broader conceptual framework. And most importantly, the high-quality lessons that teachers prepare and teach must foster student thinking. And in thinking about what they are learning, students must also self assess and be able to understand what they do not know.

What is best for students? Using a variety of teaching strategies that work for a wide variety of students. It all comes down to understanding how students learn and providing them with effective, high-quality instruction.