RACE CARS (Compressed Air Cars)

1. RACECARS (Compressed Air Cars) 8th Grade Ind. Tech Miss Check

2. Table of Contents Unit 1- Understand the Problem Unit 2- Gather Information Unit 3-Develop Solutions Unit 4-Implement a Solution Unit 5-Test and Evaluate Unit 6-Redesign and Communicate

3. Unit 2 – Gather Information

4. Aerodynamics and Drag In this activity, you will: -Gather information about the Compressed Air Car Design project. -Evaluate how drag and weight can affect a car’s aerodynamics.

5. Explore Drag Glossary Aerodynamics-As a car drives down a road, air flows around it. The way air flows around cars and other objects is studied in aerodynamics. Engineers use what they learn in aerodynamics to design fast cars, boats, airplanes, and even rockets. Drag-As a car drives down a road, the air flowing around it resists its motion and slows it down. The force that slows down the car is called drag. A race car engineer’s goal is to minimize drag so a car can move as fast as possible.

6. Glossary Continued.. Form Drag- Recall that drag is a force that slows a car down. When drag is caused by the shape of the car, it is called form drag. Designers try to minimize form drag by streamlining a car body. Streamlining is shaping a car so that it has the smallest amount of drag when air flows around it. Transition Point- When air flows over a car, it follows the shape of the car. If the smooth air flow is interrupted, it moves away from the car and flows in many different directions. It swirls and twist in little pockets of air, called eddies. This air flow is turbulent. The location where the smooth air becomes turbulent is called a transition point. Eddies

7. Yellow Car This car body is level and even. Because the transition point is at the rear of the car body, the air flow is streamlined over most of the car body. Race Time-23.12 seconds

8. Blue Car This car body is blunt. Because the transition point is at the middle of the car body, the air flow is streamlined over only about half of the car body and turbulent over the other half of the car body. Race Time -24.28 seconds

9. Red Car This car body is rough and choppy. Because the transition point is at the front of the car, the air flow is turbulent over most of the car body. Race Time - 26.95 seconds

10. Complete Questions Numbered One Through Four

11. Summary Aerodynamics studies the way air flows around objects. Drag is a force that slows a car down. Form drag is drag produced by the shape of the car. Streamlining is shaping an object so that it has the smallest amount of form drag as air flows around it. A transition point is a location where smooth air becomes turbulent. The ideal car body has a transition point as far back on the car as possible.

12. Aerodynamics and Weight Glossary Aerodynamics- Recall, aerodynamics is the study of the way air flows around objects. Engineers use aerodynamics to develop fast cars. Weight- The weight of a race car can affect how fast it moves. Weight is a measure of the force of gravity on an object. It is a measure of how heavy an object is. The car’s weight is a result of the materials that are used to build a car and the way those materials are used. Often specifications establish the minimum and maximum car weight allowed for competition.

13. Car Weights Yellow Car This car has a standard body design and is made from light materials. Because none of the car’s center section has been hollowed out, it is heavier than the red and blue cars. Race Time – 25.31 seconds

14. Car Weights Blue Car This car has a standard body design and is made from light materials. Because some of the car’s center section has been hollowed out, it is lighter than the yellow car, but heavier than the red car. Race Time – 22.60 seconds

15. Car Weights Red Car This car has a standard body design and is made from light materials. Because most of the car’s center section has been hollowed out, it is lighter than the blue and yellow cars. But when this car races, it does not offer enough support to the wheels and axles. The axle will break through the wood, and the car cannot finish the race. Top View Race Time – N/A

16. Complete Questions Numbered Five Through Seven

17. Summary Weight is a measure of how heavy an object is. The weight of a race car can affect how fast it moves. The ideal car weight is one that is as light as possible, but does not sacrifice its strength. Congratulations! You have completed Unit 2- Gather Information. You will now move onto Unit 3. The power point is titled “Unit 3 – Develop Solutions”.