Conversation between children and teacher

Teacher : Have you ever heard of Isaac Newton?
Student : Yes, Madam.
Teacher : What did he discover?
Student : Law of Gravity.
Teacher : Let me tell you how he stumbled upon this discovery.
He was sitting on the ground looking at an apple
tree. An apple fell on his head. This led to the
discovery. What do you understand from this?
Student : Had he been sitting in a class like this and listening
to you as we are doing now, he would never have
discovered the law of gravity.