I'm not sure what "which has more sugar" science project is. I'm guessing you want to measure the difference between liquids of about equal volume that contain dissolved sugar, and want to know which one has the most? If so, then you can use either an equal-arm platform balance like the one on the website link, or you can use an electronic scale (the same website has these too). Either way, if you want to be "scientific" you should represent the difference in grams and not ounces. Science uses the metric system. Good luck.