This report investigates the effect of wheels on the speed of a solar car. This is achieved by considering the effects of force and energy transformation and what happens if extra wheels are added. Force is the act of pushing or pulling on an object with mass that causes it to change velocity (e.g.: accelerating a car). Force is also a vector which means it has both magnitude and direction. Energy transformation aka energy conversion is the act of changing energy from one form to another. An example of energy transformation is a kettle being boiled when the electric energy is converted to heat energy. These two laws of physics are found in a solar car as the sun produces energy which is captured by the solar panels on the car. The cars use hundreds of photovoltaic cells to convert sunlight into electricity.
This electricity then powers the engine which enables the car to move - the petrol has been replaced as fuel by the sun. This majorly impacts the environment as petrol has been replaced, meaning reduction of greenhouse gasses. The sun is also a renewable source meaning it’s always there (during daytime) and unlimited. Besides the solar panels, wheels are one of the important parts of a car, using friction to keep the car on the ground, move and stabilize the car. As most regular solar cars have 4 wheels, the independent variable chosen was to add 2 more wheels to the car to verify if the number of wheels effect the speed of a car.
I predict that the 6-wheel, modified car will travel slower than the 4 wheeled car as more wheels are in contact with the roads surface which increases the friction causing the car to slow down.
- A solar powered car was built using a 20 cm x 12 cm plastic car base, cables, a 2.5 cm x 2 cm motor, double sided tape, 4-wheel stabilizers, 2x16 cm x 0.5 cm wheel poles, a 16 cm by 8.5 cm solar panel and two pairs of 3 cm plastic wheels.
- The solar car was then tested out in the sun and the results were analysed and recorded.
- The chosen modification was then added to the solar powered car. (an extra two pairs of wheels)
- The new car was then tested with the modification and a 2nd pair of results were collected
- Both pieces of data were then compared and analysed to see whether the modification improved the car.
- A science report was then written based on the data results collected.
The results can be applied in a real-life situation as follows:
- Extra wheels offer increased stabilization perhaps improving safety
- Extra wheels also mean cars travel at a slower speed (as demonstrated in our experiment) as being more in contact with the ground’s surface may result in less car crashes occurring
- However additional wheels also consume more resources meaning it could take a lot more money and time to build a more advanced model.
This experiment shows how force and energy transformation can change the velocity of a car and effect it in a number of ways. For example, applying more force may speed up the car while having more wheels may result in more friction result in the car slowing down.
This test was designed by timing the original car then comparing these results to another test with the modified car. This test concludes that the modified car lost speed of 11.6% (on average) as it was in more contact with the road which resulted in a loss of speed. However, the test was slightly unfair as the track was in a different position during both tests and the day was less sunny on the day of the modified car’s test, perhaps giving the original car an advantage. The wind on the day of the modified car’s test was also a lot stronger resulting in a loss of speed as it was being pushed to the side rather than forward. I think if we retested the cars, we would have to have the same weather conditions and same track position in order to make this a fairer test. An aspect that would be enjoyable to explore next time would be whether the color of the car would impact the speed of it as black and darker colored cars may prove warmer in strong sunlight, rather than the brighter colored cars.
A few questions that arose after this experiment included
- What would be a back up fuel source if the sun didn’t shine?
- Would a different sized wheel impact the speed of the car?
These questions would conclude in a different result and a great idea to test out in the future.
The evidence shows that adding two more wheels to a solar powered car decreases the speed of by an average of 0.07 m/s (11.6%) meaning that there are more points of contact to the road’s surface resulting in more friction.
Original car materials:
- 20 cm x 12 cm plastic car base
- a 2.5 cm x 2 cm motor
- double sided tape
- 4-wheel stabilizers
- a 16 cm by 8.5 cm solar panel
- two pairs of 3 cm plastic wheels
- 16 cm x 0.5 cm wheel poles
- 2 x 3 cm plastic wheels
- 2-wheel stabilizers
- 1x16 cm x 0.5 cm wheel pole
- Though co, 2019, What is a Force in Science? Viewed 25/08/2019 https://www.thoughtco.com/force-definition-and-examples-science-3866337
- Solar Power is the future, 2018, How Do Solar Cars Work? Viewed 29/08/2019 https://www.solarpoweristhefuture.com/how-do-solar-cars-work.shtml