The 5 E's is an instructional model based on constructivism that has 5 phases - Engage, Explore, Explain, Elaborate, and Evaluate. Each phase builds on the last with students first connecting new ideas to past knowledge, then exploring concepts through hands-on activities, explaining their understanding, expanding their knowledge by applying it to new examples, and finally evaluating their own learning. The model is intended to help students actively construct understanding rather than passively receive information from the teacher.