Ideally, Project-Based Learning environments should open up opportunities for learning in ways that make the content functional for the students. The content is accessed, constructed, evaluated, and used in service of a more complex project, so the utility of the content learned is apparent.
Students can see the practical application of the things they are learning.
Two principles that underlie good projects also help students see the functionality of the content. The students should be given the opportunity to generate some of the content themselves. Many students wonder when they are ever going to use the stuff that they are learning. If the problem they are working on is based on adult work practice, the students will see the utility. Some ways to connect the project to real-world work is to have students search the Internet, have an expert in the field give a talk to the class, or show the class newspaper or journal clippings related to the topic on which they are working.