One potentially interesting idea is to write a psychology case study of a particular individual or group of people. In this type of paper, you will provide an in depth analysis of your subject, including a thorough biography. Generally, you will also assess the person, often using a major psychological theory such as Piaget's stages of cognitive development or Erikson's eight-stage theory of human development . It is also important to note that your paper doesn't necessarily have to be about someone you know personally. In fact, many professors encourage students to write case studies on historical figures or fictional characters from books, television programs, or films.
Third-graders could also try to tackle subjects such as recent wars, deforestation, laws regarding texting in cars, animal research or food safety. Homeschooling, violent video games, improving education, ending childhood obesity, whether soda or junk food should be banned from schools, kids and smoking, and dangers of drugs are also topics. While some of these may seem a bit beyond the scope of an 8- or 9-year-old child chances are they already have some knowledge and some opinions on the subjects. Allowing them to read on the topics at their grade level will likely engage them further in learning about the issues.