Your child’s curiosity and refined language skills will aid him in asking open ended questions, i.e seeking details to satisfy his query.
Through practice and providing ample opportunities where he listens and responds to open ended questions, will get him familiar to ask similar questions as well as answer these questions in more complex ways.
What you need to know
While reading a book to your child, ask him questions like, “What all did Goldilocks see in the bear’s house? OR ''Can you guess what will happen next?'' OR ''How will the story conclude?” etc. This way he will attempt to elaborate the answers.
Similarly, to satisfy his ‘need to know,’ he may ask questions where you need to provide more details. For instance, “Why some objects sink while others float?”