This study explores the impacts of popular music education in classroom practices from different aspects such as learning by ear, motivation, musicianship, peer learning and creativity. The Sing by Ear approach was created based on the concepts of informal learning in singing a cappella. A total of 323 participants aged 11-14 were invited to participate in the 3-month project. Students learnt to sing cover songs by ear in an a cappella setting instead of reading music notations. The result from the case studies showed that students gained positive experiences in musicianship, peer-learning and peer-teaching, confidence and satisfaction, and creativity following the project. A pedagogical model was proposed based on the literature and findings in the study to inform the research and practice in popular music education for teachers and researchers.