Having background knowledge is a prerequisite for academic success. One key way for teachers to help students with background knowledge is to teach vocabulary. This will then help give students the ability to talk about new concepts and make specific connections using academic language as opposed to general connections using everyday language.
For example, Student A could describe the water cycle as, “The water goes up and makes a cloud. Then gets heavier and it can come down. This can happen again and again” This shows that the student understands the concept of the water cycle. But their language suggests that they only understand it on a basic level.
Student B, who has a higher level of vocabulary can describe it with scientific language which provides greater depth. “The water evaporates and then becomes a gas. When it cools, it will condense and form a cloud. When the water droplets come together, gravity can pull them down as a form of precipitation. This process will repeat.”
Obviously, this is a simplified example, but by having the content vocabulary, a student is able to not only show that they understand the structure of the concept. They are able to demonstrate that they understand the processes of that concept.
It also gives the teacher much more to work with. If student A says something incorrect, it is more difficult for the teacher to assess which part of the concept the student does not understand because they explained the water cycle in generic terms with a generic vocabulary. Whereas if Student B makes a mistake, the teacher will be able to provide correction more easily since the student has more background knowledge to draw on (vocabulary) and they used most of the vocabulary correctly, more clearly showing both what they know and do not know.
Another important factor. The even if Student A perfectly understands the water cycle (albeit in generic language) he will fall further behind in future units that build on previous unit’s vocabulary. This makes it important for teachers to stress vocabulary and test it (to make sure students have learned it). Learning vocabulary will help students catch up and give them the ability to think more critically about whatever concepts they are learning.