Comparing fuel economy in different cars

Introduction

This activity is suitable for students studying a topic on fuels from age 14 to 16. Students need some prior knowledge of fuels. Knowledge of kinetic energy is desirable but not essential for this activity.

The teachers' PowerPoint presentation explains that fuel consumption is an important consideration when seeking a car that produces low output of polluting gases. Students are given data about a variety of makes and models of cars and are asked to determine which factors are important in affecting the fuel consumption, as measured by the number of miles the car will travel on one gallon of petrol.

Measuring fuel consumption

There are some interesting points to be made about units and choice of measurements.

Fuel consumption is measured in terms of miles per gallon, which needs some explanation. Scientists work with SI units of litres and km. There are instances when data are presented in a different form, but it is advisable to use them as they stand. It is possible to find data about the power of the engine, but the time taken to accelerate from 0-60 mph is a good enough substitute measure in this instance.

Students are asked to see if there is correlation between any of the factors: i.e. mass, power, fuel type, size of engine and the fuel consumption. They can do this with Excel. Click here to see the student worksheet.

Fuel type

Fuel type is a major factor and therefore it is useful to filter the data for petrol cars and correlate these with the factors. The next step is to correlate diesel cars with the factors.

Students can extend the data set with reference to magazines. They could explore whether diesel produces more polluting gases and particles than petrol.

New car design

The Insight car mentioned in the final slide of the presentation is a new engine design that incorporates an electric engine with a traditional fuel-burning engine. The combination gives low fuel consumption. Click here for more information about this innovative car from the Science NOW! archive.