Post on 11-Dec-2015
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 )
Go speed racer!Challenge #2: Design the most energy efficient car
Using the supplies provided, design and build the most
energy efficient car …fastest and cheapest wins!
Energy-Efficient Cars
What are some special things you notice about these cars?
energy efficiency: Being able to do more with less energy.
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.
AerodynamicsAir 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
Design
Prototype
Research
Simulate
Define the Problem
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! (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)
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)
Vocabularyenergy 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
What kind of energy does your car have at
the top of the track?
What about at the bottom of the track?What is a variable? What is a control?
Why do engineers want to design energy-efficient cars?
Potential
Kinetic
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 variablethat changes as a result of a changein the independent variable, in thiscase the time it takes your car to get down the track.
Graphing Variables
0
1
2
3
4
5
6
7
0 1 2 3 4 5 6 7
Spee
d of
the
bal
l whe
n it
hit
s th
e flo
or (
mph
)
Height above floor when dropped (ft)
Example Variables
Independent Variable
DependentVariable
DRY MIXDependent variable
Responding
Y-Axis
Manipulated
Independent variable
X-Axis
0
1
2
3
4
5
6
7
0 1 2 3 4 5 6 7
Spee
d of
the
bal
l whe
n it
hit
s th
e flo
or (
mph
)
Height above floor when dropped (ft)
Example Variables
DependentVariable
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 resultsTurn in design ‘journal’ before you leave
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?