Gravity Car

For science we must create a "Gravity Car" which we will later race. In order for our cars to be counted they must be recyclable and not have anything to do with styrofoam. So I made my car out of a water bottle; for the body, skewers; for the axiles, and thread spools; for the tires. Just to make my car look nice I spray painted it black and put a strip of blue glitter down the middle. In order to make the it more dense I want to either put some water in it or put some sort of screws in it. As listed before, clearly, my car is made out of all recyclables and it will probably be faster with the water or screws. So by making this car it might go fast and it might not, we will have to see.