The importance of this research is the use of WhatsApp in physics instruction beyond the classroom. This study evaluated the content of conversations in a in a class-wide WhatsApp group of high-school physics students (e.g., the goals of the conversations, topics of conversation, the hours at which conversations were conducted, and who participated in the conversations) and the role of the physics teacher in the group in order to evaluate the value of this tool for physics instruction. The use of WhatsApp expanded the space and time in which learning occurred and allowed for closer relationships among students and, especially, between the teacher and the students. The findings demonstrate that the use of WhatsApp contributed to the understanding of physics concepts. The students used WhatsApp to further their physics' knowledge. They asked questions, asked one another for help, and shared solutions. It also broadened the role of the teacher beyond the classroom by the teacher's guidance, the creation of a supportive atmosphere and the creation of a learning community and allowing her to perform additional functions, beyond what she could do in the classroom. The unique contribution of this tool to physics education, is that it allows for open, immediate discussion of students' questions, which allows for their difficulties and misconceptions to be addressed. This use of WhatsApp made physics studies more accessible for students and more relevant.