Students learn how the aerodynamics and rolling resistance of a car affect its energy efficiency through designing and constructing model cars out of simple materials. As the little cars are raced down a tilted track (powered by gravity) and propelled off a ramp, students come to understand the need to maximize the energy efficiency of their cars. The most energy-efficient cars roll down the track the fastest and the most aerodynamic cars jump the farthest. Students also work with variables and plot how a car's speed changes with the track angle.

In some cities, especially large cities such as Los Angeles or Mexico City, visible air pollution is a major problem, both for human health and the environment. A variety of sources contribute to air pollution, but personal vehicles account for one of the main sources. Though each car has relatively low emissions when compared to vehicles of the 1970s, there are so many more cars on the road now that their emissions play a large role in overall pollution. In this activity, students think about alternate ways to power a vehicle to reduce emissions. Student teams design an eco-friendly car using the engineering design process, and make a presentation to showcase their product.

Students search for a French brand car to describe and then play a 20-questions style game with partners to guess and figure out what each other's selected cars look like.

Students take a closer look at cars and learn about some characteristics that affect their energy efficiency, including rolling resistance and the aerodynamics of shape and size. They come to see how vehicles are one example of a product in which engineers are making changes and improvements to gain greater efficiency and thus require less energy to operate.

Students explore the use of wind power in the design, construction and testing of "sail cars," which, in this case, are little wheeled carts with masts and sails that are powered by the moving air generated from a box fan. The scientific method is reviewed and reinforced with the use of controls and variables, and the engineering design process is explored. The focus of the activity is on renewable energy, as well as the design, testing and redesign of small cars made from household materials. The activity (and an extension worksheet) includes the use of kinematic equations using distance, time traveled and speed to enforce exponents and decimals.

Students learn why shock absorbers are necessary on vehicles, how they dampen the action of springs, and what factors determine the amount of dampening. They conduct an experiment to determine the effect of spring strength and port diameter on the effectiveness of a shock absorber. Using a syringe, a set of springs, and liquids of different viscosities, students determine the effects of changing pressures and liquids on the action of a model shock absorber. They analyze their data through the lens of an engineer.

Students apply their knowledge of constructing and programming LEGO MINDSTORMS (TM)NXT robots to create sumobots - strong robots capable of pushing other robots out of a ring. To meet the challenge, groups follow the steps of the engineering design process and consider robot structure, weight and gear ratios in their designs to make their robots push as hard as possible to force robot opponents out of the ring. A class competition serves as the final test to determine the best designed robot, illustrating the interrelationships between designing, building and programming. This activity gives students the opportunity to be creative as well as have fun applying and combining what they have learned through the previous activities and lessons in this and prior units in the series. A PowerPoint (tm) presentation, pre/post quizzes and a worksheet are provided.

Looking at transportation and the environment, students learn that some human-made creations, such as vehicles, can harm the environment. They also learn about alternative fuels and vehicles designed by engineers to minimize pollution. The associated hands-on activity gives students a chance to design their own eco-friendly vehicle.