After finishing the construction of the racer, there were two rounds with two races each of controlled testing. In one race, the car is powered by the battery, and in the other it is powered by the solar panel. Each race is 5 meters long in both of the testing rounds. The first round focuses on the base car that we made before any adjustments were made to the car. The second round is testing the car with the slight modifications to it and seeing if it improved the efficiency of the car.
One discrepancy in the data is that each round of testing was done on different days leading to a difference in the amount of sunlight the solar panel was exposed to. The After Data represents the testing with the tinfoil side and the small wooden slab under the plastic platform. The tinfoil, according to the data, inhibited the car. The extra weight of the additions caused the car to move slightly slower even if the tinfoil did slightly increase the voltage output of the solar panel.
The slight decrease in speed cost our team first place in the class competition races.
Our team took fourth place when the car was powered by the solar panel, but we took first place when racing with the battery.
The tin foil did not improve our racer's efficiency. If we were able to redo our additions, we would increase the angle of the tinfoil side so that the light that hits it reflects directly onto the solar panel instead of right back at the light source.