A perceived dichotomy holds sway in science education: Educators think that they can either stress inquiry learning, using lots of hands-on experiences, or stress content knowledge, decreasing hands-on learning and proportionately increasing direct instruction. You can do one or the other, this viewpoint implies, but you can't do both.
From developing curriculum and working with teachers around the United States, I know this viewpoint is incorrect. To get a sense of how inquiry and content are frequently cast as mutually exclusive, imagine yourself as a teacher in the following pair of scenarios.
Scenario 1: Inquiry Only
You are a 4th grade teacher in a school district that emphasizes inquiry-based learning. The district's philosophy is that if students are given opportunities to use well-selected science materials, they can discover science concepts on their own or with little help. Through such hands-on experiences, students will approach subject matter as scientists in the field do.
You've been implementing this inquiry-based curriculum for a while, and you're troubled. The kids have a great time doing hands-on science, but they don't seem to be discovering the science concepts that you had hoped they would. In addition, the parents are less than thrilled that their children aren't learning traditional science. The district curriculum committee shares your concerns, citing research on the ineffectiveness of unguided inquiry (Mayer, 2004), and your state's science assessments are coming up fast. Given this scary situation, your district pulls an about-face. They declare that it's time to deemphasize hands-on, inquiry science and to adopt a content-driven approach so students will learn the basics.
As a preview of what kind of teaching you might expect to see in your school after this shift, consider scenario 2.
Scenario 2: Only the Traditional
You are now a first-year science teacher in a high school, with a bachelor's degree in education and significant science coursework under your belt. You're assigned to teach the introductory chemistry classes. As a brand-new teacher, you look to your previous high school and college teachers as models of how to teach a science course. You begin with some combination of lectures and assigned textbook readings and progress to having students solve textbook problems, attend discussion sessions, and look at illustrative solutions to problems. You also have your charges perform experiments in labs, which enable them to see that concepts learned in lectures and readings apply in the real world (or at least in the school lab).
Now imagine you're back to being that 4th grade teacher who is switching to a content-driven curriculum. Does this switch mean that you have to start teaching “traditionally,” as described in scenario 2?
Conventional wisdom would answer yes, but the purely traditional approach is not your only option. You can use hands-on activities in a meaningful way to help students build a fundamental understanding of science concepts using a model known as the Learning Cycle (Atkin & Karplus, 1962).
Zeroing in on the Three Es
The Learning Cycle was first introduced as part of the Science Curriculum Improvement Study, a program that focused on elementary science. The most recent and well-known interpretation of the Learning Cycle, developed by the Biological Sciences Curriculum Study (BSCS) curriculum development team (1988), uses “the Five Es”: Engagement, Exploration, Explanation, Elaboration, and Evaluation. By guiding students through these five ways of approaching science concepts, teachers can give students the freedom to discover through exploration, yet guide the search so that students can't help but bump into the target knowledge.
In the Engagement phase, teachers expose students to questions and activities that engage their prior knowledge of the domain in question; in the Evaluation stage, they assess students. I'll concentrate on the middle three Es here, because they show the heart of the Learning Cycle.
In the Exploration phase, students perform hands-on activities designed to “set them up” for understanding a concept. Instead of explaining the concept beforehand, the teacher structures experiences from which students can draw an understanding of the concept.
For example, suppose you want to teach students the law of reflection: The light reflected off a surface leaves the surface at the same angle that the light hits the surface. In the Exploration phase, you might have the students investigate how different beams of light reflect off surfaces by asking them to measure certain angles and look for a pattern in those angles. You would not give students flashlights and mirrors, tell them to mess around a bit, and hope they'll discover the relationship. That's the kind of procedure that has given hands-on science a bad name.
In the Explanation phase, teachers draw on the explorative activities just completed to explain the new concept. In our light example, you would explain that the angle of incidence of a light ray is equal to the angle of reflection of the light ray. If you've structured your Exploration activity well, students will be able to apply labels (such as angle of incidence) to the phenomenon that they have already observed.
Activities in the Elaboration phase involve leading students to apply their learning in a new—and often hands-on—situation that reinforces and initially assesses their learning. In an Elaboration lesson connected to the light example, a teacher might show students an arrangement of mirrors, give them a protractor, and tell them to predict where a light ray would ultimately end up if that ray were bounced off the mirror arrangement. It's crucial that the activity present a new situation that relies on concepts previously encountered. Thus students don't rely on memorization to accomplish the task.
Sounds Great—But Is It Effective?
At this point, you may ask whether teaching with the Learning Cycle, which is more time-consuming than other approaches, truly helps students understand concepts better. Lawson (1995) provides a thorough summary of the research, and Ates (2005) provides further confirmation of the Learning Cycle. In their 1988 study, Renner, Abraham, and Birnie studied how effectively teaching high school physics using the Learning Cycle helped students learn science content. They also examined whether the order in which the Learning Cycle phases were presented had any influence. Switching the order of the phases can actually result in the two different instruction scenarios I've contrasted here. For example, presenting the Explanation phase before the other two phases approximates the lecture/labs format (scenario 2). Presenting the Exploration phase first and the Elaboration phase second without including an Explanation lesson leads to unguided hands-on instruction in which teachers hope students stumble upon key science concepts (scenario 1).
Renner's investigations showed that the normal sequence of the Learning Cycle—Exploration, Explanation, Elaboration—is the most effective method for all learners tackling new subject matter. Presenting the Explanation phase first—which is similar to starting out with a lecture format—did help many students grasp review content well. But even with review material, students who were at a concrete, rather than formal, level of reasoning (Piaget, 1970) learned most effectively through the normal sequence of the Learning Cycle.
Other researchers have found that a teacher's clear understanding of the concepts to be learned and of how they will tie into the Exploration activities of the Learning Cycle is essential to the mix. A recent NSTA Reports article (National Science Teachers Association, 2003) revealed that one of the primary predictors of a science teacher's success is that teacher's content knowledge.
Making Choices: The How and the When
Research on the effectiveness of the Learning Cycle sheds light not only on how to teach inquiry science without skimping on content, but also when to do so. Considering the vast amount of content that district and state guidelines now require schools to cover, science teachers can't realistically use the Learning Cycle to teach all information or every concept. Teachers using inquiry methods must make choices. You might decide, for example, that the measurement of distances and angles is so easily learned that a trip through the Learning Cycle isn't worth the extra time, and you might reserve the cycle for such difficult concepts as color addition and subtraction or Newton's second law. Deciding when to use the Learning Cycle involves some tough choices. But for my money, such decisions are more palatable than making the choice between teaching science using hands-on methods or teaching for content.
