Many children will go back to school in a short while, so I put myself a question: How would I use Google for my school projects, if I were in high-school again? Let's see:
For math, I could use Google Calculator for unit transformations and to compute complicated expressions. Google Scholar would be helpful to find interesting papers.
Geography would be more pleasant with Google Earth and Google Maps. Imagine all the great photos I could include from Google Earth. I would also use Google search to learn the capitals, the flags, facts about population, area or language. Just type: "Iran flag" or "capital of Iran". For economical information, I would definitely check out Gapminder.
For history, I would type historical events or figures in Image Search and try to imagine the whole scenes. I would also use Google Directory to find high-quality sites, like the ones about Napoleonic Wars.
For chemistry, I would learn more about interesting experiments with Google Video. Google Search may show information about the elements.
Google Earth would be nice for Biology too. The content from National Geographic would make a virtual visit to Africa possible.
Google Groups is helpful to solve many computer science problems. I could find interesting books with Google Books and even read some snippets from important books.
Google Translate would help me learn more foreign languages, I could use the define: operator to find word definitions, Google's spell checker to improve my English, Image Search to know more about art, Google Video to listen classical music, and Writely to write some of my papers or collaborate with my colleagues. I would also use Ask.com for the related searches that are useful to explore a field.
Sometimes you can be a better kid if you have some nice tools. They can't replace good books, but they can complement them.