Gravity accelerates everything equally. Whether you can SEE that depends entirely on how far you drop it — short drops hide air resistance, long drops exaggerate it.
Over a metre or two, nothing has picked up enough speed for drag to matter, so almost anything lands together and the mass question looks settled. Over fifty metres the light object has long since hit terminal velocity and lands seconds later, so it looks settled the other way. Same objects, same physics, opposite conclusion — which is why the question survived two thousand years and needed a vacuum to answer.
Only for objects dense enough for drag to be a small correction. A feather and a hammer differ at any drop height in air, and no height reveals equal acceleration without a vacuum — which is exactly why the demonstration was worth doing on the Moon.
Estimate with the rule, then check it against the calculator that models it properly.
Open Galileo Drop Experiment →