Student in the experimental group were instructed with inquiry-based instruction supported 5E learning cycle. In the instruction based on 5E learning cycle method, teaching and learning activities and lesson plans were designed to maximize students active involvement in the learning process. The topics included in the lesson plans were about the three units of fifth-grade sciences book; they included: hidden strangles (microbes, viruses, diseases, body’s defenses ways, helping the defense of the body, and vaccines); nervous system and sense organs; and human and environment.