One thing you can do is a quick study into latex. Below I've added a link to an activity which you can adapt into a science project. Try it with and without oil, and with different width sticks (such as a pin, a bamboo stick, a sharpened chopstick, etc.) Try and figure out why sometimes the latex balloon pops and sometimes it doesn't. Why does the oil help? Answering questions like these will help you understand the properties of latex (which is important to know about as its used in more than just balloons).