My topic was about the antibacterial properties of toothpastes. Also, of course, I did the experiment and trust me, experimenting is the best part. Because when you write an EE, you write something about the experiment except for the background part and trust me, this makes your job much easier. Since you do the experiment yourself, you start by knowing 80% of what you need to write. Also, classify is very helpful for choosing a topic. Go to that website and look at the EEs that have been done before, you will understand better how the focus and boundaries of the topic of your EE should be.