An explanation is a nonfiction writing that describes a procedure (such as how something works or why something happens). The primary distinction is that explanations explain something, whereas instructions tell someone what to do. For example, "Turn off the gas now" is an instruction; "Push the button on the wall" is an explanation. Explanations are used in many types of writing. They can be found in scientific papers, essays, and reports. They're also used during teaching sessions when explaining concepts or procedures. Finally, they're used by service professionals when explaining their services- for example, an accountant might write an explanation of bookkeeping methods for her clients. Book reviews, magazine articles, and interviews all require the use of explanations. In these cases, an author needs to distinguish his or her own opinions about something with facts and examples. This helps readers understand what is being said while not being swayed by emotion or personal preference. Books and movies have always used explanations to guide readers or viewers through complex subjects or processes. Modern authors still use explanations in their own writing- for example, an engineer might write a detailed explanation of how engines work for readers who want to build their own vehicle. Professional writers should be able to provide detailed explanations because they need to communicate complicated ideas and procedures to others.