Driving Question: How can we design a paper car to safely transport an egg during a head on collision.
Purpose The object of the Paper Car Crash Design Contest is to apply your science knowledge and skills to design and build the most crashworthy car that includes a minimum of 3 safety design features. Crashworthiness will be based on two criteria: 1. The car with the greatest momentum at the time of collision, and, 2. A car in which the occupant (egg) is neither injured (cracked shell) nor killed (broken shell) as a result of the collision. Materials (per student or pair of students) Copy paper, 2 sheets (81⁄2 in. x 11 in.) Wheels and axles (2 sets), Plastic drinking straw (only used for axle housings), Glue, Colored pencils, crayons, and markers for vehicle decoration (no stickers or paint) Design Considerations Should your vehicle be rigid and strong (like a 1950s muscle car) or is it better if it collapses (like an Indy racing car)? Should the occupant (egg) be able to move freely in the vehicle or should it be strapped tightly to the vehicle? How can your vehicle be designed to easily remove and inspect the egg after a crash? Design Product/Presentation Your challenge is to design and build a car with the greatest momentum (i.e., fast and massive) using only two sheets of copy paper and unlimited amounts of glue for the car’s frame and body. Your paper car must be able to carry a raw egg down an inclined racetrack ramp and protect it during a crash with a concrete block. Read the rules/specifications listed below before beginning your design process and remember that in order to win, you must have BOTH a car with the greatest momentum AND an egg occupant that survives the crash unharmed. On the day of the car crash contest, you must introduce your design to the class and identify at least 3 safety design features you incorporated into your car’s design. Rules and Specifications 1. Maximum car width: < 6.5 centimeters (including axles and wheels) 2. Maximum car length: < 16.5 centimeters 3. Minimum car mass without the egg: > 40 grams 4. Glue, paper, wheels, axles, and the straw-axle housing are the only construction materials allowed. The entire frame of the car must be made of paper and glue. 5. Your vehicle will be disqualified if it exceeds length and width dimensions, does not meet minimum mass requirements, or contains stickers, paint, tape, cardboard or any other non-licensed materials that contribute to the structural integrity of the vehicle. 6. Vehicle designs must allow for easy access to and removal of the egg (occupant) for inspection after the crash. 7. Vehicle designs should be able to withstand 2-3 trials/collisions without parts replacement or repairs. 8. All vehicles must visibly display the following information on their frames: a. vehicle name b. builder’s name c. vehicle length in centimeters d. vehicle mass in grams Lab Report Criteria Submit a report that fully addresses the following criteria: 1. Purpose (2-3 sentences): Provide a brief statement describing the project and how it is relevant to your real-world experiences. 2. Variables (2-4 sentences): Identify & define the quantities you are measuring and the independent, dependent, and controlled variables that will affect your vehicle’s performance. 3. Materials: List materials and quantities used to construct your vehicle. 4. Methods (2 paragraphs): Describe your building process. Summarize the problems you encountered during the building process and how you solved them. 5. Photograph or Diagram (1 page): Include a photograph or large hand-drawn picture of your vehicle. Label key design features (e.g., crumple zones, safety cage). 6. Data: Construct a data table that provides the following (include measurement units): a) distance traveled by vehicle b) total time of run (measured with stopwatch) c) width of vehicle d) length of vehicle e) mass of vehicle without egg occupant f) mass of vehicle with egg occupant g) width of photogate flag h) time for photogate flag to pass through photogate timer at end of run
7. Calculations: Show all equations and calculations used to obtain the quantities listed below. final velocity = width of photogate flag ÷ photogate time Calculate the vehicle’s momentum before impact using this equation: momentum = (total mass of vehicle with egg) x (final or average velocity) 8. Performance Assessment (1 paragraph): Citing your own measured and calculated data, describe the performance of your vehicle and whether or not it met your expectations. 9. Conclusion (4-5 paragraphs): a) Explain how your vehicle’s design protected the egg. b) Compare your vehicle’s performance to another vehicle in the class. What were the strengths and weaknesses of each design? Cite data and calculations to support your conclusion. c) There is always room for improvement in a design. How would you modify your car to improve its performance? Research
· Crumple zones are structural areas in the front and sometimes rear of a vehicle that are designed to absorb energy upon impact in a predictable way.1 · When a car crashes, the goal is for the structure to crush in a relatively gradual, predictable way that absorbs much of the impact energy, keeping it away from the occupants in what is termed a “controlled crush.” 2 · Crash test results from the National Highway Traffic Safety Administration’s New Car Assessment Program (NCAP) indicate that occupant injury and fatality risk can be reduced by designing vehicles with softer front end structures resulting in larger “maximum crush,” provided there is no intrusion.3 · Newton’s first law states that an object in motion will stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force. As a result, if a vehicle is going 50mph, the bodies inside are as well, and if the vehicle hits a solid wall and comes to a stop immediately, the bodies will want to continue going in the same direction at 50mph.1 · Passengers will continue to move forward at the same speed until they come in contact with a part of the automobile or another human being, causing injury. Even after a human body comes to a stop in an accident, its internal organs continue to move, slamming against each other because of the impact, often causing serious injury or death.4 · Newton’s second law of motion, force = mass x acceleration, conveys that as the time it takes for an automobile to come to rest or change direction is increased, the force experienced by the automobile (and its occupants) is decreased. Conversely too, if the time to stop is shorter, the force experienced is greater. Crumple zones add time to the crash by absorbing energy.5 · Crumple zones allow the front of the vehicle to crush like an accordion, absorbing some of the impact of the collision and giving some off in the form of heat and sound. The front of the vehicle effectively acts as a cushion that slows the time it takes for the vehicle to come to a complete stop, applying less force on passengers, which could help save their lives. Source: (http://www.plastics-car.com/Todays-Automobiles/Automotive-Safety/Physics-in-the-Crumple-Zone-2.html)
Vehicle size and weight matter. Smaller, lighter vehicles generally offer less protection than larger, heavier ones. There is less structure to absorb crash energy, so deaths and injuries are more likely. People in lighter vehicles also experience higher crash forces when struck by heavier vehicles. If safety is a major consideration, pass up very small, light vehicles.
A crashworthy design reduces death and injury risk. Structure and restraints help determine crashworthiness. Good structure means a strong occupant compartment, crumple zones to absorb the force of a serious crash, side structure to manage the force of a striking vehicle or struck object and a strong roof that won't collapse in a rollover. Safety belts keep people in their seats and spread crash forces across the upper body's stronger bony parts. Airbags protect people from hitting things inside the vehicle or objects outside it.