Fair use weighs heavily in favor of educational uses. So in most cases, using images and/or videos you’ve found online for your presentation for class is not going to land you in hot water. Why is this? Using an image or video that belongs to somebody else without permission for an educational use is not likely to impact the potential market, it is only being shared with the people in your class, and it is being used to educate yourself and others. It is still always good practice to cite where the content came from and try to use openly licensed content that allows people to use it without seeking permission first (see “Creative Commons” section below) whenever possible.
This text helped me understand that using images or videos found online for school projects is generally allowed under "fair use." I hadn't realized that, as long as it's for educational and non-profit purposes, using someone else's work is usually fine. I also learned that it's important to credit the source of the content and use content under open licenses, like Creative Commons, when possible, to avoid copyright issues