Fuel Efficiency
Fuel Efficiency is how far a car can travel on a set amount of gas.
A measuring cup holds exactly one cup of juice. One cup can fill three small glasses or just one large glass. The small glasses each hold less, so the juice goes further across more servings. Fuel efficiency works the same way: the same amount of gas takes some cars much farther than others.
Explaining fuel efficiency by grade level
Think about a car driving down the road. Some cars use a lot of gas to go a short way. Other cars use just a little gas to go far. Soft tires make the car work harder, so it uses more gas.
Projects that explore fuel efficiency
Does low tire pressure really waste gas? This project tests five different cars at two tire pressure levels — each driven at 50 miles per hour on 5 gallons of fuel. The first run uses the recommended tire pressure; the second drops to 80 percent of that value. When tires are properly inflated, cars travel 2 to 4 percent farther on the same fuel before the low fuel signal lights up.
How much farther can a car travel on the same fuel at a slower speed? Five different cars each run on 20 liters of gasoline — first at a steady 90 km/h, then again at 110 km/h. Every car goes 20% to 30% farther at the slower speed, and that difference holds across all five models tested.