In our personal experience, the hardest part about a science investigatory project is simply coming up with a good idea. And we suggest that for your investigatory project you find a topic that's both novel and useful.
Check out this science tutorial to learn how to make a bar of soap out of guava leaf extract, which was made by Dragonknight15 and fellow peers for their third-year chemistry class. This guava-infused soap actually helps clear up acne. You'll need sodium hydroxide, guava leaves, containers, and lavender scent.
If you'd rather make liquid soap, we've got another great guide for you to follow:
Want to master Microsoft Excel and take your work-from-home job prospects to the next level? Jump-start your career with our Premium A-to-Z Microsoft Excel Training Bundle from the new Gadget Hacks Shop and get lifetime access to more than 40 hours of Basic to Advanced instruction on functions, formula, tools, and more.