you dont teach them how to think, you give them space to make mistakes and learn from them, and when they lack a quality that they need to solve a problem, you wait until they exhaust themselves and then you give them a hint (not a direct one, but one bound to the domain they need to learn). you keep doing this. and you tell them to question their selves. and through experimentation you tech them not to take 'failure' as failure but to understand the bigger picture and that they are just confirming through failure. they are working on a problem. and they should never associate their self image with the thing they are studying. and tech them to study all sides to get the bigger picture. not just individual pieces. and have fun. if the kids not smiling or looking excited/anxious about the results. then something is not right. let them lead the course. you are just like a good psychologist. supposed to sit there and help them not to do stupid and dangerous stuff. but ultimately you let them self develop and grow at their own pace in their own way.