Quite often we get kids who come to school as five year olds eager to learn and offer explanations for everything they see and enthusiastic to speculate in their pursuit of new knowledge. What they learn very quickly is that the big kid behind the big desk knows "the right answer" and it becomes their job to figure out what "the right answer" should be according to the big kid. This happens for seven years. Then we send an academically timid, cautiously curious kid on to junior high or middle school, who has had their imagination on the shelf for much too long. We also create a perception by teachers that they have to know all the answers to be good teachers.
Good science education is always discovered and never force fed.
To avoid both pitfalls, may we suggest presenting open ended questions to your students that have the following characteristics:
And since you asked ...
A Catholic priest and a Jewish rabbi, who both happened to be instructors at their respective schools, were having lunch one day. During the conversation the topic of teaching styles came up and the Catholic priest looked over and said, "You Jews always answer a question with a question. Why is that?" The rabbi looked up, shrugged his shoulders, and replied, "Why shouldn't we?"
So, when you do an experiment, extend it. Once the kids get the general idea, ask them to expand on it. My short list is below; it can be applied to almost any experiment in one form or another.
Manipulate the experiment in a way that there is more than one way to solve the problem. Creativity is required, the kid is the ultimate judge, and if it doesn't work the first, second, or even the two hundred and forty-first time, that's science. Good science.