How can you use copyright for educational purposes?

Answer 1

In order to use copyrighted materials without permission you need to establish the project as "fair use"

The four primary factors you need to consider are...

1. the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
2. the nature of the copyrighted work;
3. the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
4. the effect of the use upon the potential market for or value of the copyrighted work.

Answer 2

By obtaining the permission of the copyright owner, or by waiting for the copyright to expire, which at least in the US will occur approximately never since Disney (in conjunction with other large copyright holders) owns the US Congress in fee simple and keeps getting extensions passed.

Some jurisdictions have a concept of "fair use" that allows certain specific usages of copyrighted images without the explicit permission of the copyright holder, but you should really consult a lawyer who's familiar with copyright law in your jurisdiction as opposed to trying to figure this out yourself based on what you heard on the internet.

Answer 3

Unless it falls under "fair use" or other exception of copyright law you will have to seek permission from the copyright holder.

Answer 4

You ask first, and if they say you can't, you don't. Then go and make something similar, but slightly better.