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Me05 Zinc and copper in Galvanic Cells and in one orange battery
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In a previous
experiment you have made elektricity by connecting two different metals.
Now you will assemle other Galvanic Cells and a battery.
Left: Cut a
piece of zinc from the beaker of an empty dry cell. Ask an electrician
for short pieces of insulated copper wire. Remove the insulation.
* Puncture a lemon or an
orange with a zinc sheet a(Cu) nd a copper wire (Cu). Connect the metals
with a multimeter. It will read 0.97 Volt (and a current of
few mA).
* Middle: Cut an
orange or a lemon into two pieces. Puncture each half by a Cu electrode
and a Zn electrode.
* Use a wire with crocodile
clips to connect the Cu of the left cell with the Zn of the right
one.
* Connect the free Zn und
Cu electrode with the terminals of the multimeter. It will read the
douible voltage 1.88 Volt
* Right: The model
visualizes what happens in the metals, in the wire and in the liquid while
electricity is flowing:
1. Zinc atoms push
electrons into the wire. (Zn --oxidation-->
Zn2+ + 2 e-).
2. Electron flow
through the wire from the Zn electrode to the Cu electrode),
3. H+(aq)
of the juice pull electrons from the copper electrode [2 H+(aq)
+ 2 e---reduction-->
H2(g)]
4. Negative ions
of the juice flow from the positive to the negative electrode.