As a student you always need to credit the sources you use, even if it is open source or CC0.
COPYRIGHT
CREATIVE COMMONS
PUBLIC DOMAIN
For more reading and fun examples check out the following information from Capilano University Library and the University of Alberta Copyright Office.
Student work falls under the Fair Dealing right contained in the Copyright Act.
Fair dealing allows you to copy from a copyrighted work, without the copyright owner's permission, if the copy is for one these purposes:
Students still need to cite all sources.
Neither the Copyright Act, nor the decisions of the courts interpreting fair dealing set out exactly what is fair in any particular instance. One must consider all of the relevant factors, including: