A Home-Made Daniell Cell [252]
An effective Daniell galvanic cell may be constructed from
material costing very little money. A common tin tomato can with a
copper wire soldered to the top forms the jar and positive
electrode. A piece of discarded stove zinc rolled into an open
cylinder of about 1-1/2-in. diameter, 5 in. long, with a copper
wire soldered at one end forms the negative electrode.
To make the porous cell, roll a piece of heavy brown wrapping
paper, or blotting paper, into a tube of several thicknesses,
about 5 in. long with an internal diameter of 2 in. Tie the paper
firmly to prevent unrolling and close up one end with plaster of
paris 1/2 in. thick. It is well to slightly choke the tube to
better retain the plaster. The paper used must be unsized so that
the solution scan mingle through the pores.
Two liquids are necessary for the cell. Make a strong solution in
a glass or wooden vessel of blue vitriol in water. Dilute some oil
of vitriol (sulphuric acid) with about 12 times its measure of
water and keep in a bottle when not in use. In making up the
solution, add the acid to the water with constant stirring.
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