Remember to use the scientific method when testing your solar boat! Hold other variables constant as you change and explore individual questions.
• Experiment with different propellers. Which propeller makes the boat go faster?
• What do you think would be more effective: a small propeller at high RPMs, or a larger propeller at low RPMs? Can you conclude anything about whether two blades or three blades would be better for a boat propeller?
• Try your boat with and without a rudder. What happens to a boat with no rudder?
• Does your boat go faster without the drag of the rudder? Can you make it go straight without using a rudder? Can you make it spin around in a circle?
• Adjust the angle of the solar panel. Try to get your solar panel to catch the most sunlight! Prop up the panel to change the angle. Use your protractor to measure this angle. What angle works best for you? Of course, you should take into account what direction your boat is facing, and what time of day you are testing.
• Experiment with different boat hull designs. How can you optimize your boat shape? Try different hulls; you can make a great hull out of two plastic drink bottles arranged next to each other. Use tape to mount the deck, motor, and driveshaft on top of your bottle boat. Also try cutting a 2-Liter bottle in half (the long way) to make a classic boat shape. Be creative, and try to come up with the best boat design you can. What factors make a better boat?