Sulfuric Acid is corrosive and toxic.
Lead Dioxide is toxic and an oxidizer.
Chemicals and Solutions:
Two Lead electrodes
0.1 M sulfuric acid
D.C. power supply
Two Aligator-Banana leads
One 400 mL beaker
Fill the 400 mL beaker approx. 2/3 full with dilute sulfuric acid.
Curl one end of each lead electrode and hang it on the rim of the beaker such that the other end dangles into the dilute sulfuric acid. Place both leads in the solution, making sure they are not touching.
Connect the electrodes to the D.C. power supply.
Turn up the voltage to approx. 6V. Immediately bubbles will stream off the surface of the electrodes.
After a few minutes, turn the voltage off and show students the surface of the lead electrodes. One electrode will be covered with dark brown lead dioxide.
Now connect the lead electrodes to the digital read-out and see what voltage your battery reads.