Carl Sagan was a devoted educator who spoke to children of all age groups. His observation was that children are intensely curious, spontaneous with their questions, and infectious in their desire to learn. They're unafraid of looking ignorant and leap at the chance to explore. Teens, on the other hand, introverted, afraid of looking stupid, anti-intellectual, and have been beaten down by a culture and system that doesn't value scientific exploration or education in general. His opinion was that children are born natural scientists and have their intellects bored out of them.
On the other hand you have the view that children are extremely magical thinkers, natural teleologists, and incredibly gullible. Children will leap to any explanation that seems, to them, plausible. Ask a child and you'll learn that clouds are for raining, rocks are for animals to scratch themselves. Tell a child anything and you will be believed.
So which is it? Are children natural scientists or natural theologists? Will they explore and learn or will they make crap up and stick to it regardless?
Neither extreme is true.
Children are natural explorers and they're driven to learn. Just put them in any new and interesting environment and watch as they explore the shit out of it. Part of the problem of childhood gullibility, in my opinion, arises from this. They're built to take in new information and put it into a comprehensive worldview. That's an aspect of scientific exploration.
Children can be natural theologians, as well. They don't just explore and discover; they're willing to make shit up at the drop of a hat. They develop and explore wild fantasies just as easily and happily as they'll explore a natural history museum. They're also thoroughgoing teleologists1 from an early age. Show a non-speaking infant a video of a square and a triangle moving across a screen, one after the other, and the infant will register surprise when the one "stops following" the other. These are aspects of theology.
But children aren't full scientists or theologians. Leaving aside theology as a useless practice not worth exploring, science isn't just curiosity. It's hard work. It's a systematic approach to asking and answering questions, to collecting and analyzing data, to questioning your own assumptions. As Einstein said, science is 1% inspiration, 99% perspiration. Childhood provides inspiration in abundance, but the discipline and hard work simply isn't there.
1 - Teleology, ascribing purpose to things. Like how the appendix in other animals is used to break down plant-matter and in humans to cause death.