Check out an op-ed by Jyotsna Vijapurkar about Teaching Science in our schools. Interesting one.

Similarly, photosynthesis — the process by which plants make glucose from carbon dioxide and water — is `taught' years before children are introduced to the idea of atoms and molecules and basic chemistry. To water down this difficult concept, textbook writers resort to phrasing it in what they believe is simple language for children: "plants make their own food." Put yourself in the child's shoes for a moment. Do you not wonder: "so do people" (in the sense of cooking)! "What does the plant's own food look like?" "Can you see it in the plants?"

Check out the article. As I have argued before, she argues for nurturing curiosity. But she also argues to do that at the right age.