This one involves copper sulphate, which has risks. It is toxic to people if inhaled or ingested, and it is very toxic to aquatic creatures. So be careful how you dispose of the resulting solution (don't just pour it down the drain, see if it can be reused if at all possible).

Title: The basic principles of electro-plating.

Materials:
20 g Copper sulphate (available as a root killer, other industrial uses).
Glass beaker.
1 x D-cell battery
Electric wire
Copper wire or an old penny (before they were mostly filled with zinc)
safety pin 10
Electric switch

Methods
Clean safety pin well with lemon juice or vinegar.

Add the copper sulphate to 150 ml water
Connect (tape) the copper wire to the positive terminal
Connect safety pin to negative terminal by electric wire
Immerse the copper wire and the safety pin in copper sulfate solution
Keep immersed for 2 minutes
A coating of copper should appear on the safety pin .

Copper sulphate is so amenable to electro-plating that Copper will actually deposit spontaneously onto a metal base, no electricity required. However, the plating results are better using the battery, and the experiment otherwise demonstrates the basic principles using relatively safe and easily available chemicals.

More ideas of how to do electroplating science experiments.