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Every day there are news articles that seek to provide a scientific explanation for how or why a given natural phenomenon occurred. The topic may be climate change, nuclear energy, genetically modified food or something else that impacts the everyday lives of individuals.
Scientifically literate readers need to be able to evaluate the evidence and reasoning presented in the article or report. In addition, science students need to be able to explain the results of the investigations they conduct in science class.
All students should learn the critical skills that help them to develop and critique a scientific explanation. Two of the practices identified as essential for all students in Next Generation Science Standards (NGSS) are:
- Constructing explanations (for science) and designing solutions (for engineering).
- Engaging in argument from evidence.
Katherine McNeill and Joseph Krajcik developed a framework for teaching students how to develop and critique scientific explanations. The framework indicates that a scientific explanation includes four parts:
- A claim that answers the question being studied
- Evidence to support the claim
- Scientific reasoning that explains how the evidence supports the claim
- A rebuttal that considers and rules out alternative explanations.
They recommend that teachers begin by focusing on the first three components of the explanation. When students have developed enough experience with the concept of claim, evidence, and reasoning, then teachers can introduce the rebuttal, which is the most complex component of the scientific explanation.
They also recommend five instructional strategies that teachers can use to support students in developing scientific explanations.
Make the Framework Explicit
Before asking students to develop a scientific explanation, teachers should talk about what an explanation is. Teachers can then discuss what a scientific explanation is and introduce the framework.
Many teachers find that it is best to work with students on the claim, evidence, and reasoning first. When students really understand these three components, teachers can introduce the concept of alternative claims and how to present why they were ruled out as part of a fourth component, namely the rebuttal.
Model and Critique Explanations
When first beginning to work on scientific explanations, teachers may model the development of a scientific explanation for students. As students begin to work on developing their own scientific explanations, it is helpful to have students work together in collaborative groups and to critique one another’s explanations.
One strategy that may prove helpful in critiquing explanations is Praise, Question, Polish. In this strategy students comment on something they like and ask a question. The author of the explanation is then given an opportunity to polish or improve the explanation before submitting it.
Provide a Rationale for Creating Explanations
McNeill and Krajcik identified two rationales that teachers used for having students create scientific explanations. Some teachers emphasized that scientists spend much of their time developing, presenting, and critiquing scientific explanations. Because students were learning to think and act like scientists, it was important for them to spend time engaging in similar activities.
Other teachers emphasized the persuasive power of well- developed scientific explanations. They emphasized the value of being able to identify and present evidence in a way that will encourage others to stand in agreement with the explanation one is presenting.
Either way, teachers found that students worked harder on scientific explanations when they had a rationale for why they needed to learn to create effective explanations.
Connect Scientific Explanations to Everyday Explanations
Teachers also found value in helping students see how a scientific explanation was similar to explanations they might develop in other classes. Teachers also found it helpful to have students understand that the word “explain” is used differently in distinct contexts.
For example, when students are asked to explain a procedure, they are really being asked to describe what is to be done. They are not really being asked to do the same thing as when they are asked to explain a scientific phenomenon.
Assess and Provide Feedback to Students
Finally, McNeill and Krajcik recommend giving students a rubric that they can use to self assess a scientific explanation. The teacher can then use the same rubric to give feedback on student-developed scientific explanations.
The criteria assessed should become more sophisticated as students grow in their understanding of the components of the explanation.
This is just an excerpt. Preview Discovery Education’s article — Scientific Explanation: A Framework for Constructing Explanations in Science — below, and then download the full version for free.