Many studies have reported that students face difficulties in constructing scientific explanations (Kuhn & Reiser, 2005;McNeill & Krajcik, 2011; Sandoval & Millwood, 2005; H. K. Wu & Hsieh, 2006). Kuhn and Reiser (2005) found that constructing scientific explanations is difficult for students because it requires incorporating many different elements, including amassing evidence to appraise and revise claims, reasoning about how to support claims, connecting evidence to scientific principles, and communicating what has been understood. However, students often do not clearly interpret their inferences or clearly articulate relationships between evidence and claims in their explanations. Sandoval and Millwood (2005) found that students often fail to cite sufficient and appropriate evidence for their claims and articulate how a certain piece of evidence relates to a particular claim. H. K. Wu and Hsieh (2006) found that students tend to generate incoherent explanations from personal thoughts and fail to make logical connections between evidence and claims in their explanations. McNeill and Krajcik (2011) observed that students are often unclear about what it means to construct a scientific explanation and aboutwhat to include in their explanations. It is thus important to help students understand the importance of constructing a scientific explanation and guide them in the process of doing so. In summary, the common difficulties that students face in constructing scientific explanations include failing to cite sufficient and appropriate evidence for their claims, failing to connect evidence to appropriate scientific principles, and not clearly interpreting their inferences and articulating relationships between evidence and claims.