Alternative & Renewable Energy Solar Car Race Challenge – Level 3

1. Alternative & Renewable Energy Solar Car Race Challenge – Level 3

2. What You’ll Learn… • How to design and build a solar powered vehicle • How to engineer design features to optimize your car’s performance • How to determine the best gear ratio for your race car

3. Stuff You’ll Need… • Solar Race Car Kit • Digital Multimeter • Measuring Tape • Duct Tape Measuring Tape Tape Alligator Wires Multimeter Solar Race Car Kit

4. ePortfolio Suggestions… • Before you begin the activities in this Learning Launcher, think about and record what you already know about solar powered cars. • Explain how you decided on your race objectives. Be sure to clearly describe each of the “rules” for your race. • List and explain all the factors (variables) that you had to deal with in order to get the best possible performance from your solar race car. • Describe all the things you did while attempting to improve your car’s performance. What worked and what didn’t? • Graph the performance of your car using different gear ratios. • Take a photograph of your final design. Label each part and describe how it helped your car’s performance. • Create a narrated video of your car in action.

5. What You Should Know… What does a glass window and your solar panel have in common? ANSWER: They are both made from silicon. These lightweight solar cells are like very thin glass. They are both very brittle and will shatter quite easily. Therefore, it is your responsibility to be very careful when handling your solar panel. Don’t drop it or crash your solar car into things that could cause your solar panel to shatter. Shattered Glass Don’t remove the clear tape from the back of the solar panel. It protects the electrical connector tabs. Solar Panel

6. What You Should Know… You should already know solar cell fundamentals. You should know how to connect multiple solar panels and how to measure voltage output with a digital multimeter. You should know how the position of solar panels relative to the sun affects power output and how to orient them to maximize performance. If you are not yet familiar with these concepts, you should consider starting with a Level I or 2 Learning Launcher. Solar Panel

7. What You Should Know… Your solar powered car will have two gears (at least). Do you know why? Why do cars and trucks need gears? Your solar car needs one gear on the motor shaft and another gear on the axle of your car. These gears serve two purposes. They transfer the rotational power from the electric motor to the wheels of your car. They also transform that power because the two gears you will use are not the same diameter. The gear ratio of any vehicle is critical to its operation. If a car doesn’t have the proper gear ratio the car won’t even move. It will just sit there. You will be using gears in many of your SmartLab projects, so it is helpful to learn more about them. You can watch this video if you need to learn more about gears.

8. 10 60 1 6 What You Should Know… Determining Gear Ratios Driver has 10 TeethDriven has 60 Teeth = = 1:6 Driven60 Teeth Driver10 Teeth Motor Determine the gear ratio of your car using this formula

9. Do It! The Race is On! In this activity you will design, build and test a Solar Powered Race Car! But before you start to design your car, we need to have some rules for the race. Rules are like objectives and will determine how you design your car and how the race will be conducted. The rules are up to you! You can design a car to be the fastest over a certain fixed distance, to reach the highest top speed, to go the farthest, to climb the steepest ramp, to pull the heaviest load, etc. Be creative and think outside the box. Keep in mind that you will need a way to measure your car’s performance. Before you go on to the next slide, decide on the rules for your race. Be as specific as possible and write them down in your Project Journey Flowchart. Wins a Tug of War Carries Heaviest Load Most Attractive Design Climbs Steepest Ramp Fastest Car Most creative use of Recycled Materials

10. Do It! Solar Powered Race Car Challenge This collection of parts and some glue or tape is all you need to build a solar race car. Of course you will need to use your imagination, engineering, and research skills to make it a winning car. Notice that these parts do not snap together like LEGOS. Building your solar powered car will take planning and effort. Solar Race Car Kit

11. Do It! Solar Powered Race Car Challenge Make a list of all the design factors that you believe will effect your car’s performance. Then do your best to make a winning car. In addition to the science of photovoltaics, you will need to apply your mechanical engineering skills to build a high-performance solar race car. What are some of the things you should consider? Gear Ratio Physics

12. Do It! Solar Powered Race Car Challenge Once you’ve thought about how to design the best car for your race rules, build a test car and measure its performance. How did it do? The Basic Chassis Mounting PV Panel - Wiring Testing with Flood Lamp

13. There are lots of design variables to consider. Remember that design is often a matter of trade-offs. Improving one variable can sometimes detract from another! Do It! Optimize your design! Now think about a few design changes you could make that would improve your car’s performance. Consider various design variables and discuss them with your partner. Decide how to modify your car’s design to optimize performance. Which design factors will improve your car the most? Now make some improvements and retest your car! LIGHT INTENSITY AERODYNAMICS GEAR RATIO WHEEL ALIGNMENT FRICTION MOTOR TORQUE ANGLE to the SUN LENGTH of WHEEL BASE ELECTRICAL WIRING WEIGHT

14. Do It! Solar Powered Race Car Challenge Make a spreadsheet using Excel to help you keep track of your test results. The sample spreadsheet on the right is set up to measure performance in a specific kind of race. The format for your spreadsheet will depend on the rules of your race.

15. Extend Yourself… Natural Sun Light versus Artificial Light… Did you test your car inside under artificial light or outside with natural sunlight? What difference does the light source have in the performance of your car? How might you change your car design to optimize it for one or the other? 93 Million Miles Your geographic location has a lot to do with your chances for BRIGHT sunlight.

16. Extend Yourself… Double the Power Challenge If one is good, would two be twice as good? Try it and find out. Try connecting two PV panels together in series. Try connecting them in parallel. What works best? How much will this increase your speed and power. Can you make a hill-climbing low geared vehicle? Be creative! Try lots of different ideas! - + - + Two photovoltaic panels with three cells each connected in series

17. Extend Yourself… Alternate Materials Challenge Is it possible to use other materials available in your SmartLab to build a new race car or improve your car’s performance? Do some brainstorming and come up with a plan. Present your plan to your SmartLab facilitator for approval and then give it a try!

18. Extend Yourself… Students, scientists and engineers all over the world are hard at work on solar race car designs. There are lots of organized races at many levels of competition. Do an online search for solar car races to discover more about the latest developments in races and solar race car designs.