Paper helicopter experiment
Test rotor length with identical paper, ruler, scissors, and a timer. Drop over a clear floor from safe standing height; never climb furniture.
✅ Record the test before the first drop
✏️ Build two designs
Cut a 4 cm × 16 cm strip. Mark a 6 cm rotor section at the top; cut down its centre to make two 2 cm-wide blades. Fold one blade forward and the other backward. Fold the lower long edges inward to make a narrow body. Make a second helicopter with an 8 cm rotor section. Record all dimensions; the changed rotor length also changes body length, which is a limitation of this simple design.
✏️ Test consistently
Release without pushing from the same measured height. Use the same person to release and the same timing method. Alternate A and B for five drops each. Record awkward landings rather than quietly discarding them.
Complete all five trials per design before interpreting the means; untouched zeroes are not observations. Time values display to two decimal places, which does not imply that hand timing is that precise.
📝 Design A
📝 Design B
📝 Interpret
Calculate each mean: total time divided by five. Compare the ranges too. If the difference between means is smaller than the scatter within trials, the evidence is weak. Human reaction time limits hand timing of short falls.
For a stronger follow-up, keep body dimensions constant and vary only detachable rotor length. Repeat in still air.