Balloon Car!?

OK, so let me be the first to admit that our creation did not work as well as we would have liked it to work. :(
Our car was originally a simple light-weight cardboard body with two CD wheels in the back and a small plastic whirly-gig I found in our basket-of-junk on our kitchen counter for a wheel in the front. It was quite light in weight because at that point we were going to attach a sail to it and have the balloon face backwards thus propelling the balloon car forward with the sail. But our plans changed... "The best laid plans of mice and men may often go arye..." Anyway that's when we decided to sling-shot it down the hall with our creation called "The Chicken." It was going to follow all of the guidelines or "rules" as far as we were concerned. You see we were not going to simply sling-shot it down the hall, beacsue that was illegal. Oh no, that was MUCH too simple. Instead we would have TWO cars, one that would end up breaking the longest distance record by hurtling down the hallway from the sling-shot's force; the other (this one balloon-powered) would pull the wooden dowel out of the way of the first race car. Then zoom- down the hallway it would go.
But as I said, "The best laid plans of mice and men may often go arye..." In other words we abandoned "The Chicken" but only after a test run that proved our theory correct; sling-shooting the car down the hallway would work ten times better than any balloon powered car, mainly because it would have a greater force if it were sling-shot. So after those joyful test runs two of our team members (cough, cough: Madeline and Christian) lost faith in our epic little car sling-shot idea. They claimed that we would "get disqualified" and "the other teams would COMPLAIN," and while they were probably right I would have liked to have heard this concern a little bit earlier. Might I add that this was literally THE AFTERNOON before the final competition, and THE DAY before it was due. (SPOILER: We partially managed in the end!) Switching to panicked- procrastinating-student mode (even though we hadn't procrastinated)we made a few major adjustments to our car that afternoon.
Our car had been light weight. Then when we decided to sling shot it, so we made it heavier. In the end when we needed a super light car, we ended up with a bulky heavy car that barely moved. :( This is what we get for changing just about everything the day before the competition.
But overall we learned from our great failure, we learned not only that a bulky little cardboard car does not do well with a paper/copper wire sail, but we also learned a bit more about the physics behind why that happens, a bit more about applying scientific method (test your hypothesis, then if it doesn't work make adjustments), and we also learned about ourselves. We learned about the ways we deal with pressure in a close deadline, and we also learned about how we react when people turn down our ideas. In the end I'm happy that we failed, because that means we have room for improvement like all of science, and that proves that we are only human.

See here for the mass, acceleration, etc. for the car.

Summarized:
We started out with the brilliant idea of "sling-shotting" out car across the room with our creation that we (Luke, Madeline, Christian, and I) pet named "The Chicken." Anyway we ended up not using the chicken, and instead we created a car with a sail.

Here you can see a me as Hermione, a blurry Mary Grace, an angry Grey and an equally awkward overly-happy Landon along with "Newton's Apple" our final car that moved a pathetic 1 and a half meters.