Every age group has different needs, expectations, and abilities.
While junior and senior high school students have reasonable attention spans and have had some preparation in math and science that will help them relate to your presentation, holding the interest of students in sixth grade and below requires a bit more simplification and hands-on activity. Lower elementary students are learning concepts and becoming independent learners. The National Engineers Week Committee encourages you to reach out to younger students. Use your imagination. For instance, challenge them to have an in-class invention convention.