What is a bibliography? Why should I have one?
A bibliography is a list of all of the information sources that you looked at, read, paraphrased or directly quoted during your research process.
During your research process, you will build up your knowledge by gathering information from a variety of information sources. Information sources can be anything - a book, an online database article, a podcast, a website, even a Tweet!
At the end of your research process, you will create some sort of a product - maybe an essay, a poster, a podcast, or an interpretive dance, for example. Your bibliography - a list of all of the information sources you used to build your knowledge - is your way of saying “These sources of information are how I know, what I know.”
In math, you need to show your work: you write it all out, showing the steps you take to go from looking at the question to presenting your answer. In research, you need to show how you know what you know. In research, a bibliography is the way we show our work.
This is also called giving credit to your (information) sources or citing your sources or referencing your sources. We also do this is avoid plagiarism - citing/referencing your sources is part of your academic responsibility as a student. It is important to be honest about what work is yours, and what parts of your work come from other sources, either as a paraphrase or a direct quote.