How to Build a Water-Powered Battery for Your Calculator

14-year-old Instructables user Angelo S. Casimiro put up a step-by-step fabrication process that can be completed in as little as 10 minutes and can power a small calculator or a similar low-consumption device.

If you’re just before an exam, but forgot to buy a battery for your calculator, you can always revert to …water! Yes, you’ve read correctly: water can successfully replace the small battery of a calculator which can perform the same complicated math calculations that you couldn’t.

All you need is a carbon or a copper rod that you can take from a used AA battery, a 1x 1 inch aluminum foil, a small cylindrical container, a 2-3 inch wire, multi purpose pliers and a glue gun.