  Undergraduate lab design balances several factors: 1) simple experiments
connected with learning objectives 2) experiments sufficiently accurate for
comparisons between theory and measurements without gaps when students ascribe
discrepancies to confounding factors (imperfect simplifying assumptions,
measurement uncertainties, and human error), and 3) experiments capturing
student attention to ensure due diligence in execution and analysis. Drag
coefficient measurements are a particular challenge, though there has been some
success using accurate measurements of terminal velocities. Video shows promise
in several areas of kinematics, but the number of trials in a reasonable time
is limited, and analysis techniques to determine drag coefficients often
include numerical integration of differential equations. Here, we demonstrate a
technique with potential to measure drag coefficients to near 1 percent
accuracy using an affordable Doppler radar system and round plastic pellets
from an Airsoft launcher.
