Most students gain some experience with fire and burning from an early age. They have watched flames consume wood and other fuels, giving off smoke and leaving behind ashes or other products after the flames have gone out. Smoke and ash are the visible products of burning, so students use these as a way to trace where materials go when they burn.

Understanding how gasoline burns in a car's engine can be even more difficult for students because the actual combustion process is hidden from sight. Another potentially confusing factor is that the fuel is a liquid rather than a solid, such as wood. As gasoline is pumped into a hidden reservoir in the car, and the tank eventually becomes empty and has to be filled again, most students have no visual cues about what happens to the gas. Students may know the car is burning a fuel, but their explanations reflect misunderstandings about how this process happens inside the car, and what products are given off when gasoline burns.

Watch this video of 6th grade students in San Marcos, California, a coastal community. The purpose of this classroom video is to see students discuss their ideas about how fuels change inside a car.