We have 7 big writing projects that we work on in fourth grade. Plus, students routinely write full paragraphs in their social studies, science, and math classes.
One of our district goals is to improve our students' writing, so in fourth grade we strive to increase both the quantity and the quality of writing we expect. For example, when students enter fourth grade, they usually can write for only 8 - 10 minutes independently. By the time they leave fourth grade, students should be able to write 30 - 45 minutes at one sitting.
In addition, students get to experience many different types of writing. For instance, they learn to distinguish between different kinds of essays; they also will analyze nonfiction books and learn to incorporate tables, picture captions, and a glossary into their nonfiction picture books.
Most importantly, students will learn to LOVE to write. Many students already enjoy writing stories, but you will be surprised at how excited students are about their persuasive essays!