Library:Research Skills For Engineering Students/Module 07/Page 04

Whenever you use someone else's words or ideas, you must indicate that the information is not your own by properly citing and giving credit to your sources. This applies to any type of resource, written or otherwise (including books, articles, websites, images, personal communications, etc.).

You don’t need to cite your own experiences, observations, results, ideas, or conclusions.

You also don’t need to cite information that is considered common knowledge. Common knowledge is information that is generally known by many people. If you're uncertain if something is common knowledge, ask your instructor or a librarian!