Solar Energy Education: Preferential Rusting Experiment

This preferential rusting experiment develops concepts important for your child's understanding of the operation of circuits and therefore the way solar panels function and batteries store power. This project is best done after the nail rusting experiment listed above this one.

Parents please make sure to take all necessary safety precautions.

Materials Needed: You will need the following:

* three drinking glasses
* table salt
* three large iron nails
* some aluminium foil
* some copper wire

Procedure:

Step 1: Make sure all the metals to be used in this experiment are clean and shiny before use. That will help us to be sure that the results are not due to previous dirt on the metals.

Step 2: Place a teaspoon of salt in each glass and fill them with water. Stir the water until all the salt in each glass has dissolved.

Step 3: In the first glass place a plain iron nail. This will be the control; it will show us what would happen to the nail without any intervention. In the second glass place an iron nail with aluminium foil twisted around it. In the third glass place an iron nail with copper wire twisted around it. The setup should look like this:

Different metals react with the salty water at different rates. In the leftmost glass the iron rusts at its normal rate. In the middle glass the Aluminium reacts the fastest so it rusts in preference to the iron. As it does so it provides the iron with extra electrons which protect it from being corroded; this is called a sacrificial anode.

In the rightmost glass the iron of the nail reacts faster than the copper. It is therefore behaving in the same way as the aluminium in the middle glass; it is reacting and protecting the copper.

What Is The Importance Of This?

Preferential rusting is the same reaction type that occurs in batteries that give us both power for small portable devices and for solar power arrays with battery backup. Understanding how batteries work will give your child a great boost for later science studies.