Go speed racer! Challenge #2: Design the most energy efficient car

Go speed racer! Challenge #2: Design the most energy efficient car You are a car designer at GM. Your task is to design the most energy efficient prototype under $700. You must demonstrate a superior design to advance to the next stage and have your car selected for clay modeling. Using only the materials provided and the budget worksheet, your design must be the top performer within the budget given. (clay model really is an option for the winner )

Using the supplies provided, design and build the most energy efficient car …fastest and cheapest wins!

Why do engineers want to design energy-efficient cars?

Energy-Efficient Cars energy efficiency: Being able to do more with less energy. What are some special things you notice about these cars?

Efficient Cars…do more with less energy Have a sleek aerodynamic design so they cut through the air smoothly. Roll smoothly (Do not lose energy from friction in the wheels). Have powerful and efficient motors or use renewable energy. Are very small and light weight.

Aerodynamics Air is matter causing air resistance or drag which slows cars down a lot and makes them lose energy. Cars were designed with smooth lines like fish to help them cut through the air. Engineers test car designs in wind tunnels to see how easily they cut through the air.

Basic Framework for engineering design process Define the Problem Design Prototype Research Simulate Re-evaluate

Step one: Define the problem; Research (discuss what you know about energy efficient cars, consider materials for prototype and Sketch!)

Step two: Build a prototype Step two: Build a prototype! (Be sure to test along the way and keep accurate records for each test and any changes you make along the way. Keep a list of supplies used and amounts on your budget sheet)

Speed is distance  time Step three: Simulate (test on race track to time your car to calculate the speed and to check the performance of your design; be sure to review your budget) Speed is distance  time

Step four: Re-evaluate (analyze data, reflect on what can be improved and make changes before the final race)

Vocabulary energy efficiency: Being able to do more with less energy. rolling resistance: The force of friction acting on a rolling object by the ground to slow it down. aerodynamics: The ability of an object to cut through air (or water) efficiently variable: Something that can be changed in an experiment. control: A variable that you are careful to keep the same during an experiment. independent variable: A variable you intentionally change in an experiment. Usually, the intent of the experiment is to see how a change in this variable affects the dependent variable. dependent variable: A variable that changes in value when you change an independent variable. Usually this is the variable about which you collect data during an experiment.

3-2-1…RACE! Record time against opponent. Discuss your car’s performance, how did it compare, was it consistent, what could you change for next time? In one paragraph, explain your design team’s car

Why do engineers want to design energy-efficient cars? Potential What kind of energy does your car have at the top of the track? What about at the bottom of the track? Kinetic What is a variable? What is a control?

Vocabulary Variable – Something that is allowed to change during an experiment. Control – Something kept constant or controlled during an experiment.

Independent vs. Dependent Independent Variable – This is a variable you intentionally change during the experiment, like how much your car weighs. Dependent Variable – This is a variable that changes as a result of a change in the independent variable, in this case the time it takes your car to get down the track.

Graphing Variables Dependent Variable Independent Variable

DRY MIX Dependent variable Responding Y-Axis Manipulated Independent variable X-Axis Dependent Variable Independent Variable

Change a variable… Choose one independent variable to change, something about the car, the ramp height, etc and describe your predictions on the performance of the car. Test it… Graph your results (you and your partner choose the best graph to display your data, some may work better than others but you decide and create it) Add a paragraph to explain your results Turn in design ‘journal’ before you leave

Difference between NASCAR and NHRA? Ummmm… not so energy efficient cars. Pay close attention to design elements of this type of race car. Difference between NASCAR and NHRA?

Unique design features with NHRA Why do drivers ‘smoke’ the tires? Why is there no tread on the tires? Purpose of bars on the back? Why are their parachutes on these cars? Did you notice the tires appear to ‘inflate’ right before take off… how is this possible? How are some of these cars getting ‘lift’? Can you compare the forces in these car engines with forces in the space shuttle engines?