Hello. I just heard an email read out on radio 4 from a teacher saying that objects fall at a speed independent of their mass, and this was proved by Galileo dropping things off leaning tower of piza, and you could show this in the classroom by dropping rolled up paper and tennis balls. I am a biology teacher who also teachs physics so I spent some time on this before I taught terminal velocity as it is out of my comfort zone so- Can I just confirm that gravity does accelerate things independent of their mass but this is only properly seen in a vacuum because the minute you drop stuff in air, air resistance come into play and DOES effect speed depending on mass? I am thinking that a cannon balll and a beach ball of same size and shape dropped from a plane would have very different terminal velocities. Therefore the only reason you can get away with this in a classroom is that you are dropping things from a relatively low height and air resistance hasnt had time to affect speed significantly? I keep hearing people say things the same shape but different weights fall at the same speed but this seems to be wrong in real life - in air. Is this right or do I have to start again?