Having survived the rigors of middle school, and with sufficient exposure to physical science (including physics and chemistry), life science (including human and plant biology) and earth science, you as a 9th-grader are prepared to take on some genuinely sophisticated science-fair projects.
Such projects normally involve more than just an afternoon or evening or two of preparation; some of them require one to three weeks to complete, owing to the nature of their focus. As such, they provide opportunities for you to both learn a science topic in exquisite detail and communicate it to your teachers, parents and classmates.
Biology Project: Blood Sugar Levels
For a general biology project, create a presentation exploring the similarities and differences between Type I and Type II diabetes in terms of clinical symptoms, epidemiology, the known and proposed causes of each, and advances in treatment and management. How can lifestyle changes make a difference?
Chemistry Project: Ice Cream and the Freezing Point of Water
This two- to five-day project, from the Science Buddies website, explores the concepts of molecular mass and moles, and reveals that adding certain solutes to water can change its freezing and boiling points. As a bonus, at the end of the experiment, you will have created a perfectly edible treat.
For this, you will need test tubes, a thermometer, and an ample supply of sucrose and sodium chloride. You will also require recipe for homemade ice cream and the equipment to make some. After trying different, measured concentrations of sugar and salt in different test tubes containing newly melted ice, try to produce a mix that is still partly liquid at -10 degrees Celsius. A small baggie containing the ingredients for the ice cream can be placed in a larger baggie containing the optimal ice-solute mix, and after five minutes or of shaking, a small amount of edible ice cream should appear.
If you do not have access to this equipment or would prefer a more research-based project, explore the intriguing area of culinary science. For example, how are pathogens in the food and water supply managed in your city and worldwide? What are the greatest threats to food and water safety in the U.S. and abroad? What do people take for granted in "First World" countries that others around the world cannot?
Physics Project: Paper Airplanes
Use 8.5-inch-by-11-inch sheets of paper to come up with the ideal paper flying machine, using whatever online resources or books you can find.
For example, as recommended by faculty at the Illinois Institute of Technology, once you have built your simulated aircraft, stand about 15 to 20 feet from a hula hoop and attempt to throw your creations through the hoop. Then, try to throw your planes as far as you can in the air. Are the planes that seem to be the most accurate necessarily those that also fly the farthest? Why might this be or not be, depending on the findings? Also throw planes made by your classmates and have them try yours. Make posters detailing the basics of aerodynamics in flight, such as lift and drag, and explain how these come into play in real airplanes as well as the simulated aircraft you have created.
Alternatively, produce a project detailing the key advances in aeronautical engineering starting with the first hot-air balloons and airplanes and culminating with the Space Shuttle and International Space Station endeavors of the late 20th and early 21st centuries. What were the limitations to launching satellites into orbit before the Soviets managed this in the 1950s? What are the next great anticipated leaps forward in human space travel?