I'm not sure if you are a student or a parent, but the first thing I'd say about doing a project is to find a topic that you are interested in. Remember that there is a learning objective in assigning a project: that you get engaged and go deep into some science content of your choosing. You must know already that this website has many science fair resources. I urge you not to take the easiest project to do but to choose something that genuinely interests you so that you really learn something about the topic and about science. My advice is not to pick a topic simply because it is easy to do. Pick a topic that you are interested in and make up your mind to really educate yourself about it. I know that this may not be what you might want to hear, but I wouldn’t be doing you much service to tell you what to do: challenge yourself and learn something!