The primary purpose of expository writing is to explain something. The explanation can take many forms, some of which add audiovisual dimensions to the writing: You can explain a demonstration, give notes for a lecture, give directions, clarify a process, define an unknown element or instruct a reader in some way. All teaching is, to some extent, expository; much of our writing involves us explaining something to someone else.
Lists in An Expository Thesis
You begin to explain something in expository writing by stating a main idea, usually called a thesis. A thesis statement for an expository paper is sheer explanation without argument, as opposed to a persuasive work; more often than not, it suggests a list of topics. Example: "The life of a high school student is filled with homework, homeroom, time at home and homies." The young writer can now go on to explain his scholastic work, his interactions with school peers, his home life and his socializing.
Process Essays and How Tos
Another way to fulfill expository writing's primary purpose is showing a sequence of steps for demonstration purposes; this kind of process essay explains how something is done, what tools are needed, the problems and challenges in each step and cautions the reader should observe. This kind of expository writing is ideal for manuals and instruction booklets; for classroom use, it can be as simple as mixing a pitcher of powdered lemonade in four steps or as complex as tuning a car engine in seven stages.
"What" and "Why" Explained
The primary purpose of expository writing can often take secondary forms; its simple explanation can evolve into a compare-contrast or cause-and-effect essay. In the former, you're writing to explain points of comparison and difference between two objects: "How My Parents Are Alike and How They're Different." In the latter, you're writing to explain an effect that happens through a cause: "Why Teasing My Sister Always Gets Me in Trouble." One explains two "whats"; the other explains a "why."
Describe or Propose
There are two other ways to fulfill expository writing's primary purpose. One is description, a writing mode that uses the senses to "explain" a setting or object; the other is problem/solution, in which the writer explains a difficulty and proposes an answer for it. Whichever method you use to fulfill expository writing's primary purpose, remember that you are explaining something; in other words, you're right up there with your teacher.
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