When is background knowledge a barrier in Science education?

Prior knolwege is required for deep learning. It allows us to make sense out of new information. But what happens when a student's prior knowledge is incomplete or incorrect? These misconceptions can hinder a learners' progress in skill mastery in a specific content area such as Science. There are two strategies in this chapter excerpt to teaching new content area and addressing background knowledge.  

• The first strategy is activating prior knowledge. 
• The second strategy is building new background / prior knowledge. 

One strategy for science education is to begin the instruction by asking questions about key concepts covered in the science lesson and clarifying misconceptions prior to teaching the new concept. However, the article goes on with,  "Studies that show that when students do harbor misperceptions, prior knowl- edge activation can actually impede new learning. Preexisting ideas can dis- tort or interfere with the new content. If this occurs without intervention, students can fare poorly on tests and disregard information that conflicts with theirs."

How do you address students' misconceptions and incorrect backgrounk knowledge in Science? 

I'd love to hear your thoughts and tips.

Kathy Tracey