Every time I see this header I think back to chem lab. Is sodium metal a device? It certainly creates H2 when dunked in water. The problem was that said gas

Every time I see this header I think back to chem lab. Is sodium metal a device? It certainly creates H2 when dunked in water. The problem was that said gas ignited, leaving a little column of flame flowing down the water trough on the lab bench... So, I guess, the better story would be a device that created H2 (and O2, I guess) without the excitement. And to dream, if this could work without requiring too much power, it would be neat running a car on water. Would not have to be too pure, merely pure enough to react without side reactions.