Inquiry learning refers to an educational approach that capitalizes on students' "natural tendency of curiosity". In the science education literature, the term "inquiry" is broadly defined as a learning process that requires learners to learn in a way a scientist would acquire knowledge through research (Krajcik et.al., 1998; de Jong & van Joolingen, 1998; Sandoval, 2005; White & Frederiksen, 1998; Zimmerman 2007). A general definition for inquiry learning is given by National Science Foundation (2000, p. 2):