Probably the most interesting area for all young people is: What do grown-ups mean by “the future”? This question comes in many forms, such as speculation about possibilities (What can I grow up to be?), to speculation about the childhoods of parents or grandparents (“Did you walk to school or take a schoolbus?”) to amazement at current achievements (“Now that a man has gone to the moon, will we all live on other planets?”). Then there are the questions that transcend generations (“Why is the sky blue? Where does the sun go at night? “Are angels real?”). In formal educational settings, of course, the basics of language structure (grammar), mathematics, geography, etc. will occupy all the young minds. One perplexing question is "Where did I come from?" which can result in a physiological conversation or a religious one.
It depends on the age of the student, of course--seventh graders are much different than first graders. For this question, let's look at what you can do with fourth graders. Fourth graders are very tactile learners so they would benefit from drawing diagrams and using models. They can also speak intelligently about what they have made. Science is a very popular subject--have them research weather patterns or tectonic plates. Of course, dinosaurs are always a popular subject with elementary school students. When looking at social studies, do not go into extreme detail but ask students to think about why a character in history acted the way he/she did. Ask the student to think if they would have done something differently, or to come up with all the courses of action the historical person could have taken. If you have a group of students who can do it, have them rewrite stories from their reading books into plays, then act out those stories. The important thing is to keep the students involved. Fourth grade covers such a wide curriculum that it would be impossible to write all the topics of study here, but these are some ideas to get you started.