Saltwater battery explaination

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Hi all,

I've built a battery by putting a copper electrode and an aluminium
electrode in a beaker of salt water. It produces about 0.6V.

Can anyone explain what exactly's happening in the beaker?

Thanks

gareth

 

[Pete Wilcox]

Hi all,

I've built a battery by putting a copper electrode and an aluminium
electrode in a beaker of salt water. It produces about 0.6V.

Can anyone explain what exactly's happening in the beaker?

Electrolysis.

Cheers,
Pete.

 

[Bob Eld]

You need to study chemistry to get the details, but the short answer is
that the aluminum is being oxidized, and the energy from this reaction is
driving electrons around the external circuit to the copper. This works
with any pair of dissimilar metals in a conductive solution, with the
more active one being the cathode (negative) terminal. The greater the
difference, the greater the voltage. A little work with a search engine
will turn up as much detail as you can use.

The Cathode, Copper is the positive terminal. The Anode, Aluminum is the
negative terminal. Remember, electrons collect on the Anode making it
negative. Aluminum Ions leave the Anode and go into solution. Electrons
travel in the external circuit from the Anode and come to the Cathode where
they are "emitted" into the solution to combine with the Ions there.