Unless students have a strong prior knowledge base to construct understandings, they may form misconceptions. Then the teacher can build upon what the student already knows. Teaching is much more than transmitting information and having it told back to you.
Teaching is a transferring of ownership of skills or concepts.
Teachers are more effective when they guide students to transform a concept or skill which the teacher has demonstrated, into a concept or skill which is uniquely their own. The environment where effective learning takes place is critical. A classroom needs to feel safe and comfortable. Students should feel that their sincere ideas and answers will be valued and considered. Participants should encourage questioning and personal interpretations and not stress one right answer to every problem.