explain nuclear energy to someone from the 1920's, and he will give you the exact same answer as you just did.
it took humans thousands of years to discover that petrol could actually be used for something.
Scientists of the 1920's knew about the theoretical possibility of nuclear energy, as the Special Theory of Relativity was published in 1905. But that's not the point. Before we understood the properties of atoms, we had no way of predicting the possibility of nuclear power because we didn't have the underlying principles to build upon. However, we DO now have a good understanding of the properties of atoms and the conditions in which they will form and break bonds, etc. Under these rules, it simply isn't possible to extract energy from water without expending more energy in the process. There's an oxygen atom, and two hydrogen atoms, with two covalent bonds and no free electrons. It is in a low energy state; there simply isn't any appreciable energy to be had from it.
how many people know that gasoline crs can perfectly run on wood, the germans had converted plenty of cars during the war to run on wood, its not verry practical, but its simple and effective.
The important phrase in that sentence being "not very practical" Also. most of Germany's synthetic petroleum was made from coal (from the ground), and not trees.
and as a replie to bobdog, the internal combustion engine was initially designed to run on vegetable oil.
Not true, at least as far as I can find on wikipedia.
the conversion to fossile fuels was an economic and practical move, as in fact vegetable oil behaves better inside combustion engines, while fossile fuels require chemical additives to limit their negative effects on the engine mechanics and increase their energetic efficiency.
Very early engines ran on gases like hydrogen and natural gas, then various petroleum products, and eventually gasoline.