Experiment 4: Carbon Rods
If you want to do electrolysis to make sodium hydroxide or do other stuff, carbon rods are sometimes used as electrodes, but burning pencils to get their rods only gives thin, easily breakable clay containing pencil leads (I did that). If you have a battery (like a AA or D-cell) that says "Heavy Duty" or "Super Duty", it probably has a carbon rod inside. I took apart a heavy duty AA and peeled apart the positive side to reveal the carbon rod. I carefully removed the sides of the battery and got out the rod. Then I washed it up to remove the weird black stuff that surrounded the rod. By the way, the carbon rod is in the center, not on the sides. However, it turns out that I need a membrane to electrolyze aqueous sodium chloride into sodium hydroxide, so I will not be getting there quite yet.