Did I miss the explanation on why the water in the bottle remains level despite the bank? Is it the g-force of the turn itself countering the natural pull of gravity? It would seem the turn speed and angle weren't enough to counter it the way spinning a bucket of water at the end of a rope does.,(reply>), It's a balanced turn so you can work out the g form the angle of bank, because there's a relationship. A 2g turn is at 60° for example.,(reply>), +Brian A. Thomas The sum of the centrifugal force (yes, I actually mean centrifugal force) and gravity points to the bottom of the aircraft in the turn. Since this net vector is how things move, things will fall to the floor of the aircraft. He briefly mentioned that this isn't a 1 G situation, so in the turn he is actually pulling Gs. I'd guess about a 1.3-1.5 G turn using seat-of-the-video guessing.,(reply>), @Chris Emerson It would work on a bike or motobike too - as they turn and lean the total g-force always points from the top of the machine towards the wheels.,(reply>), @Brian A. Thomas It's the same principle though. With a much gentler angle of bank, you don't need a very tight turn to see the effect, just as you wouldn't with a bucket and rope either just being swung in a small circle near the ground.