- Define aerodynamic balance
- Explain why aerodynamic balance is important to race car engineers
- Assembled cars from Lesson 1
- Build a Race Car Assembly Sheet (as needed)
- Race Car Templates (as needed)
- Race Car Airflow Resource Sheet
- Observing Aero Balance Activity Sheet
- Make copies of each resource sheet and activity sheet for each student in your class.
Think: What is aerodynamic balance?
- Ask a volunteer to define downforce. (Downforce is the downward force on a vehicle caused by air pressure differences.) Review the Race Car Airflow Resource Sheet and the areas of high pressure air around a race car. Ask students to identify areas of high pressure (the front and back of the car, as well as at the crease of the windshield).
- Introduce aerodynamic balance, or aero balance—the pattern of downforce on a vehicle. Explain that the downforce—or high pressure pushing down on a car— can have different amounts of pressure. Ask volunteers to suggest ways that imbalance, or more downforce in one area, might affect a car. (Answers may include making the vehicle flip, spin, or tilt.)
Move: Why is aerodynamic balance important on the racetrack?
Step 1: Explain that NASCAR engineers work hard to manage the aerodynamic balance between the front and back of the vehicle. When the downforce at the front of the car is well balanced with the downforce at the back, then the car is easier and safer to drive.
Step 2: Introduce the concept of grip. Grip between a race car’s tires and the road helps the car to steer. Point out that race cars come in contact with the track at four different points (each tire). The downforce on race cars creates pressure on the tires, which in turn creates grip. One of the main goals of aerodynamic balance is to make sure there is balanced grip across the car’s four tires.
Step 3: Explain that aerodynamic balance helps keep cars level on the track as they are racing. Place a model car on a tabletop where all the students can see it. Explain that you will now demonstrate how grip impacts a race car’s steering. Apply gentle pressure to the car’s hood. Make sure students note how the car’s back wheels lose contact when pressure is applied to the front of the car. Then apply pressure to the back of the car. Make sure students note that now the car’s front wheels lose contact due to the pressure applied to the back of the car.
Step 4: Introduce the terms oversteer and understeer. Greater downforce at the front of the car is called oversteer, which causes the car’s rear tires to lose grip while the front tires retain traction. On the other hand, understeer or “push” occurs when greater downforce at the back of the car causes the rear tires to retain grip while the front tires lose traction.
Build: What are the effects of poor aerodynamic balance?
Step 1: Tell students they will use their model cars to observe aerodynamic balance firsthand.
Step 2: Distribute the Observing Aero Balance Activity Sheet and review instructions
with students. If students need help understanding how to manipulate the car, you may repeat parts of the demonstration from Step 3 in the MOVE section above.
Team Up: What happens to race cars when they understeer and oversteer?
Step 1: Tell students to conduct online research (using videos and text) to learn more about oversteer and understeer.
Step 2: Have students form small groups and tell them that they’ll be hand-printing small books. Ask student groups to fold standard 8.5” x 11” sheets of paper into halves twice to yield four evenly shaped squares (eight pages total). Instruct them to cut the paper into squares and staple their books along the edge for “binding.” Offer the class additional sheets of paper as needed.
Step 3: Ask students to work together to craft their own informational books that demonstrate and explain understeer and oversteer. In text and illustrations, have students explain what oversteer and understeer are—what is the result of each, why it happens, and what it looks like. Allow groups to determine exactly how their books will look and how much text and illustrations they’ll use.
Online Simulation: Visit scholastic.com/nascarspeed/drive for an online interactive simulation that will allow students to apply aerodynamics principles to design, then drive their own race cars!