The new generation of engineering students has grown up within the new technologies which provide opportunities like internet, smart phone environment and applications on such environment which also affects how they learn. We are starting to re-think how to teach students in this new generation, how students gain knowledge through videos before class, and how instructors guide students to clarify and apply that knowledge during class in a flipped classroom. Recently, many events aimed to promote computer programming education for K-12 students worldwide. For example, President Barack Obama stated in the video for the 2013 Computer Science Education Week annual event: ?Don?t just buy a new video game - make one. Don?t just download the latest app - help design it. Don?t just play on your phone - program it.? A popular tool for teaching K-12 students computer programming is Scratch. Scratch, a visual programming environment, allows students to create their own personally meaningful interactive content (interactive stories, games, music and art). This study explored the effects of on-line self-learning and the validity of on-line peer assessment in high schools and to analyze effects of various types of peer feedback on students. Participants were 111 senior high school students enrolled in a Scratch programing course. Following procedure was performed during the class for 18 weeks: the students watched the on-line video materials, gave feedbacks, and formed 33 groups of three or four to create Scratch game projects, viewed other groups? work, and performed assessment on the Web-based learning and assessment system. The peer assessment activity consisted of three rounds. Pearson's correlation analysis was conducted and the results indicated: 1) students significantly improved their projects as involving the peer assessment activities; 2) the peer-assessment results and teacher assessment results were without significant differences, indicating that peer assessment in high school could be perceived as a valid assessment method; 3) the on-line video materials feedback and end-of-project final score were highly consistent. This study also examined the relationships between the types of peer feedbacks in which students obtained from peer assessment and the subsequent performance of their projects. Corrective peer feedback was useful in helping students? development of better projects.