Optional Extensions & Variations
Depending on how much time you'd like to devote to this activity and how much depth you'd like to go into regarding the statistics of multiple trial or variance of multiple factors in an experiment, you can optionally extend this activity in a couple of ways.
Performance of a particular battery will change from one flight to another. The battery might be more fully charged one time compared to the next. The flight pattern, even when students attempt to perfectly replicate the same pattern each time, will vary slightly, draining the battery more or less quickly.
Test each battery more than once. This could involve different groups of students testing each battery. Discuss with your students the range of outcomes. What was the average flight time across all batteries? For a particular battery? How much variation was there between batteries? How much variation was there from flight to flight with each battery? Were some batteries more variable than others?
Discuss with your students the ways that one UAV might vary from another. Might the motors be better in one than in another? Might one UAV have better propellers than the next? Help them realize that the performance of a particular battery in one UAV might be different than in a different (though supposedly identical) UAV of the same model.
Test batteries in different UAVs. Try battery #1 in UAV #1, then in UAV #2. Then try battery #2 in each UAV. Compare the results. What matters most, which battery is being used or which UAV it is flying in? What is the range of variation: a little or a lot?
Discuss with students the factors they should keep in mind to conduct "fair tests" as they move forward with their UAV flights.
You could buy batteries from different companies and see if there is any systematic variation between brands.
Some UAV models may support use with batteries of different capacities. For example, the SYMA model we used in our tests shipped with a battery rated at a capacity of 500 mAh (milliampere-hours). Higher-capacity 1200 mAh replacement batteries are also available via online shopping sites. Do the higher-capacity batteries last more than twice as long as the lower-capacity models, as one might assume based on their respective ratings? This would make a good comparison for students to explore.