The technique to extract hydrogen and oxygen from water is called electrolysis. Electrolysis involves passing an electric current through water, which splits water molecules (H2O) into hydrogen gas (H2) and oxygen gas (O2). This process typically requires electrodes and an electrolyte to facilitate conductivity. Hydrogen gas is produced at the negative electrode (cathode) while oxygen gas is produced at the positive electrode (anode). Electrolysis is widely used both in small scale experiments and large-scale industrial production of hydrogen.