Pinewood Derby Q&A

What is the effect of types of wood on the speed of pinewood derby cars?

I am not in boy scouts I am in the science fair and that is my question if you have any links to places that may help please post them

Public Comments

1. Different types of wood have different density, so naturally they weigh less or more. If you use lighter woods you will have a lighter car and thus it will effect the performance. On a slope start, a car made with more dense wood would accelerate faster but would slow down quicker on flat surfaces due to this increase in weight.
2. use a lighter wood and put your weight up front
3. This is one site that answer all your questions! http://members.aol.com/randywoo/pine/
4. PINEwood derby cars are of course made of pine wood. However, I listed a link below to a site that could help you. A general rule of thumb though is that the lighter woods will go faster to start, but the heavier ones, on a steep hill will have a greater force pushing them to go faster (think of a truck on a highway versus a small car). There are different types of pine and I would suggest googling that.
5. As a previous answer stated, different woods (and even different pieces of the same type of wood) have different densities and thus different weights and may affect speed accordingly. But if your underlying question is about the impact of materials on speed, your selection of wood is minimal compared to other factors. Since there is a maximum weight allowed for cars your choice of wood would not materially affect your car's speed as much as just buying the regular pinewood kit and using lead stick-on weights to reach the maximum weight (which would also give you the flexibility to place the weight where you wanted it - front, back, center, etc.). One factor that has a far greater impact on overall performance is making sure the axles are square to the body of your car, because, to paraphrase Jonnie Cochran, if your wheels ain't square, you ain't going nowhere. If your axles are perfectly square to the car body your wheels will turn smoothly and not slow your car down by jumping up and down or wiggling back and forth across your lane. Another important facter is the "freeness of spin" of your wheels. You can sand the axles and use graphite power for reduced friction. I'm not sure if this is exactly what you're looking for, but in the grand scheme of things, wood type does not have a great impact on car speed.