Help with model car experiment

[cypher21]

I have to create model cars powered by different types of energy, such as solar, wind(or balloon-powered), or rubber bands, and test which one makes it move the farthest. I know how I'm gonna make each car but I'm not sure how I would go about testing them. How should I control the energy inputs and whatnot? I want to know how I should test the cars and make it as accurate as possible.

[bfinio]

Hi - unfortunately for some of these types of cars, it's going to be difficult to measure the amount of energy input to allow you to keep that constant for a comparison between cars. There are two different overall types of cars listed in your experiment - those that rely on release of initially stored potential energy (like the energy stored in a stretched rubber band or an inflated balloon), and those that have a continuous energy input from an outside source (like a car blown by a fan or powered by the sun with a solar panel). So to start, you cannot really do a fair comparison between cars that start with a limited amount of stored energy, and cars that have a continuous source of energy. For example, a balloon car will always stop eventually after the balloon is fully deflated and the car has coasted to a stop, but in theory, as long as it's a sunny day and you have enough space, a solar car will just keep going.

You could narrow your experiment down to only test cars that have initially stored potential energy. For example, you could test a car that starts on an elevated ramp (gravitational potential energy), a rubber band car (elastic potential energy), and a balloon car (a combination of elastic potential energy of the stretched balloon itself, and potential energy of the compressed air in the balloon). There are equations that let you calculate the amount of potential energy stored in each device, but that will be a lot of physics for me to explain in a forum post here, and will require you to do your own background research first.

Hope that helps!