When it comes to the issue about what's the best way for a teacher to help students interested in a subjects, people's opinion differ from person to person, and culture to culture. Some people may simply think students would have interest in a specific subject after the teacher explains the important role it plays students' later career. While others may have more creative ideas, such as it is better for a students to have curiosity via comparing the subject to the specific courses they have already taken. So, explaining the subject will help the students outside school may be a good way, but not the best way.
It is really very naive to simply thinks one would be interested in somethings just by explaining the powerful use and benefits after master it. Because it is not directly make them interested in somethings. How many students just be told the harm of over immersed in the video games? And they still play that day and night. How many wonderful advantages have been illustrated to students after learning a specific one, like how the physical theory can explain the complex phenomenon in life or how the marketing theory can make us be a success businessman? Lack of interest can still be found after the skillful and talented teacher tell the students about all these. Why? Sometimes, students may just don't like the subject itself even though they have already known the wonderful experience after they learn it well.
Complicated and abstract theories probably timid students from having interest and studying the subject. Some students would just clever enough to enjoy the excitement of contemplating every detail reasons for some theories to make sense. While others may just be stopped at the very beginning without the ability to learn the new things from the concepts they have already known. It's better for the teacher to give a direct and vivid interpretation of the theory itself to make these students continue exploring themselves. For example, when the teacher tells students the concept of gravity. The concept may be well accepted by students with the start of explaining why apple would drop to ground rather than the sky. This would better than saying the various application of this concepts, such as this theory was a foundation of manipulating the satellite.
In conclusion, explaining the subject that may assist the students outside school may not be the best choice for teachers, who may make the students more interested in it via adopting a more easy understandable way to show the concepts in the subject.