My first YouTube video

This happened four days ago. I was busy with my exams, pulling off all-nighters and walking like a dead zombie when I was informed that I have been selected by my college as one of the candidates for Google’s student facilitators. They told me that I will be shortly contacted by mail, and they did. They asked me to post a video of me explaining any topic in simple terms within a day. So, I had to attend my exams, take a video, edit it and post it on YouTube within a day and the worst part was, I haven’t even decided on a topic yet.