Copyright infringement is a serious offense and while it oftentimes goes unnoticed in educational settings, we must realize it is important to learn and practice legal media use so we don't get into trouble when using media for business and personal endeavors in the future. Imagine getting fined thousands of dollars for using some else's creative work without permission! Any image, video, song, story, article, or other creative work is protected by copyright laws the second it is created, meaning permission must be granted by the creator for others to use it. Here are links to media resources that already carry this permission, therefore they are completely free to use for projects and presentations:
Google Advanced Image Search - change "usage rights" to "free to use or share"
Free Music Archive
Dig CC Music