I have been trying to work out some information about the Laws of Energy and have come to a stand still. For example if you take a molecule of water, it contains a finite amount of energy, e.g. you can't produce energy out of nothing (according to the laws of energy), so if it takes so much energy required to split the water, you get the same amount of energy back by combining the hydrogen and oxygen to make water. So how does pressure effect the rate at which water can be split? If you had a litre of water in a 1.5 litre air tight pressured container with electrodes and started splitting the water at what point would the pressure in the container be too much for the water to be split? Or does pressure not have an effect on the rate and energy required to split water? Secondly if you allowed the hydrogen and oxygen to float freely up to a fuel cell above, when the fuel cell combines the hydrogen and oxygen back into water it also creates electricity and heat (The same amount of energy that is required to split the oxygen and hydrogen in the first place) but with that water now sitting above the electrolyzers below, you could in turn send the water back down a tube to where the electrolyzers are and have it spin a turbine on the way down, in thoery meaning you get energy from gravity's effect on molecules. So when people say that there is limited energy in everything, how does it take into consideration gravity's effect on matter and things like kinetic or potential? Because the water falling down is gravity causing the water to generate kinetic energy. So in theory it is possible to create a device that uses the same matter to generate excess energy as a result of gravity? So if there is a limited amount of pressure you can create in a container before it effects the electrolysis process (Amount of energy required to produce the hydrogen and oxygen) is that pressure going to be enough to spin a turbine (Similar to using a compressed air canister to spin a turbine). I want to test this theory out, but fuel cells are expensive, so was hoping someone with a physics back ground could provide me with some feedback.