Hi again,
I'm glad you liked the suggested ideas.
In terms of using a question, I suppose you could use a question in the informative part of your title. For example, you could use one of the suggestions above and then tie it in with your question.
In order to create your question, I would advise you to use your independent and dependent variables. Your essential question should be able to guide you in finding this.
In terms of making it like a "hook" for audience members, you could say something like:
"What's in your facemask?"
"Monsters in your mask: what is the effect of wearing a facemask on bacterial growth?"
I am not familiar with projects that have had titles that are questions, but I certainly like your comparison to essays and books, and I think that as long as your title is informative and includes your Dependent and Independent variable, it should be great.
Let me know if you have any other questions
Stay nerdy,
lmp1341