In a voltaic cell, current is produced by connecting an oxidation reaction half cell to a reduction reaction half cell in an electrolyte solution. Oxidation and reduction reactions (redox reactions) are chemical reactions involving a transfer of electrons from one atom in the reaction to another. When two different oxidation or reduction reactions are connected electrically by connecting the cathode to the anode, a current is formed. The direction depends on the type of reaction taking place at the terminal.
The first step would be to determine metals to be used as the cathode and the anode.
The type and length of a lunar eclipse depend on the Moon's proximity to either node of its orbit. ... A total lunar eclipse can last up to nearly 2 hours, while a total solar eclipse lasts only up to a few minutes at any given place, due to the smaller size of the Moon's shadow.