Watch this amusingly constructed video that generally outlines Fair Use, which is a legal defense in the US. The video will start part way in - go back to the beginning for a review of copyright basics.
Some of the details (e.g. how long copyright lasts) are different in Canada and the US.
In Canada, we don't have Fair Use, we have Fair Dealing. However, it operates in much the same way.
Fair Dealing allows use of copyrighted materials without having to ask or pay the copyright owner. However, it is limited to specific purposes (test one) and within a range of parameters (test two).
Fair Dealing includes use for educational purposes, research and private study. However, within those categories, there are limits on how much you can use, whether you can make money on what you create, etc. If you change the nature of your use, for example, you stop being a student and want to use student work for commercial purposes, you can lose fair dealing exemptions.
According to the Canadian Copyright Act:
29 Fair dealing for the purpose of research, private study, education, parody or satire does not infringe copyright.
29.1 and 29.2 outline how fair dealing can be used for parody/satire or news reporting, as long as the source and creator are mentioned.
Even if you qualify for fair dealing because you are using the copyrighted item for one of the uses above, it's not a free-for-all. You still need to moderate your usage of the item according to the factors below.
In other words, even as a student, you can't copy a whole book or draw an illustration based on a comic book character, then sell it.
There are no set laws or rules to guide how much is allowable of any of the factors. Each case that becomes part of the legal system through a lawsuit is judged on its own merits with the factors in mind.