Stupid Penny Batteries Part I: FAIL

©2014 Beret Olsen
©2014 Beret Olsen

posted by Beret

Ages:  Persons of most any age can do this project as unsuccessfully as I did.

I had such a good time making lemon batteries last year that I got VERY EXCITED when I discovered another way to make batteries out of ordinary, every day objects. Lemon batteries were awesome. Lemon batteries were easy. So why not try penny batteries? I’ll tell you.   

Optional additions:  zinc washers. A flask.
Optional additional materials: zinc washers. A flask. A better project altogether–preferably one that works.

What you need:

*A bunch of pennies

*100-grit sandpaper

*About a half cup of vinegar in a glass or dish

*Some heavy cardboard–enough to cut into little pieces to sandwich between the pennies

*A small piece of aluminum foil

*Scissors for cutting the cardboard

*Something that could use a small battery for power. My plan was to use LEDs, which are cheap and handy. I still had a couple lying around from the pocket flashlight project a few weeks ago. Other options that might be equally inoperable:  cheap calculators, digital timers, or small bulb and socket combos, like you can get from Sci-Supply.


cardboard cut

1. Cut the cardboard into pieces that are roughly the size and shape of the pennies, but  slightly larger. Drop them into a container of vinegar to soak.

Submerge the cardboard, so it absorbs the vinegar.
Submerge the cardboard completely, so it absorbs the vinegar evenly.
2. Sort through your pennies. For this project, you will need pennies minted in 1982 or later. Prior to 1982, pennies were predominately comprised of copper, but starting in 1982, pennies were made out of 97.5% zinc. We need to expose the zinc on one side of each penny. The copper side is supposed to function as the positive terminal, or cathode, and the zinc as the negative terminal, or anode. Click here for more information about the ingredients of pennies throughout history, and here for a general explanation of how a battery works.
©2014 Beret Olsen
©2014 Beret Olsen

2. Use 100-grit sandpaper in an attempt to remove the copper coating from one side of each of the pennies. This was by far the most frustrating step–an issue which was perhaps exacerbated by the fact that I was sick and terribly cranky. I tried a couple of things to help make it easier and/or faster. I put all of the pennies on a piece of duct tape–sticky side up–then wrapped the tape around a block and sanded like crazy by hand.

sanding block

When that did little, I dug out my spouse’s finishing sander.

I love this Makita for many, many reasons, but not for this project.
I love this Makita for many, many reasons, but today it did not meet expectations.

That helped more, but after a while, the pennies were so thin that I was sanding the duct tape into a sticky mess, while the last bits of copper somehow continued to evade sanding. Though I got close, I never did figure out how to successfully remove all of the copper from one side. I did try to build a battery with my substandard pennies, however. I stacked them on the small piece of aluminum foil:  first, a penny copper-side down, followed by a piece of vinegar-soaked cardboard, another penny copper-side down, cardboard, and so on, ending with the zinc side of the fifth or sixth penny. I could not light an LED. Nothing.

first cell

It was time to try a new approach.

In some ways, this was a relief. The noise from the finishing sander was reverberating uncomfortably through my congested skull. And though pennies are practically useless in the real world, I still felt a little guilty for destroying them. Perhaps my failed attempts were karmic retribution for defacing federal property.

Close, but no cigar. Three of the reasons I can never run for President.
Close, but no cigar. Three of the reasons I can never run for President.

The good new is, I can also show you how to make a non-functioning battery using intact pennies sandwiched with zinc washers.

4. Place one zinc washer on a small piece of aluminum foil.

5. Blot the excess vinegar off of a piece of cardboard and place it on top of the washer. Then, put one unadulterated penny on top. That makes one cell. We will need five or six cells to generate enough power to light the LED. Supposedly.

zinc washer sandwich

6. Continue stacking the same three items in the right order: washer, cardboard, penny–until you have a stack of five cells. End with a penny on top.

7. Try lighting an LED by putting the negative (short) end on the foil. Touch the longer end to the top penny. Watch it not light. Voilà. Frustrating, no?

Here’s the link to the video I watched six million times for assistance–to no avail. He certainly makes it look easy.

My plan is to go to bed and stay there for as long as the tiny tyrants will allow, and then get up and miraculously produce a functioning penny battery. That’s my plan. I’ll let you know if I succeed.

Author: Beret Olsen

Beret Olsen is a writer, teacher, and photo editor for 100 Word Story. She loves toast, the Oxford comma, and all your comments and questions.

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