On Day 12, Donna started science class by reviewing what students had done the week before, when they were using ramps to race toy cars. She first listed various ideas that students had about making the toy cars go further in their races. For this day's experiments with toy cars, Donna proposed a more uniform approach.

She proposed that students use toy cars that are (nearly) the same type, so no one has an advantage. She asked her students what would happen to the class experiment if someone did have an advantage, such as having a different type of toy car, and they concurred that would not be fair. Donna laid down other parameters for the day's experiment, including limiting the experiment to ramps (so students couldn't do "anything we want") and forbidding anyone from pushing a car to get it started down the ramp.