This study explores the possibility of facilitating students' learning of a difficult science concept like buoyancy through integrating metacognitive approach into a web-based, multimedia science learning program. It specifically examines the learning environment created during use of this metacognition integrated on-line multimedia science program in their science classes and also investigates its impact on students' cognitive and affective learning outcomes among different learning styles and grade levels. Results show that students perceived their learning environment created during the use of this online science program in their science class as highly positive. Students were satisfied with the program and their cognitive outcomes increased after learning science this way. In particular, students' cognitive outcomes were also found to be higher when students perceived greater student cohesiveness, involvement, investigation, task orientation, cooperation, equity, self-efficacy, and the teacher used more challenging questioning. This study demonstrates that the use of metacognitive approach with multimedia web-based science learning program indeed facilitates students' cognitive and affective learning outcomes with learning difficult concepts.