Hey hey, I’ve got a twofer in the current issue of the Physics Teacher! One is my article on the chemistry behind the saltwater battery. The other is an article on blogs that physics teachers can use. I’ll post the full blog article (the published one was cut quite heavily) a little later!
Here’s the crux of the saltwater activity: When you connect cups filled with salty water together, you can make a current strong enough to ring a buzzer or light an LED. Neat! This article explains the electrochemistry behind this popular activity so that physics teachers can know enough chemistry to understand a lot of the weird behavior that they see. I’m a physicist, so I don’t know much chemistry. So this paper is kind of neat in that it’s a joint venture between myself and my dad, retired physical chemist Dennis Chasteen. My mentor Paul Doherty is also a co-author.
The construction of the cell is largely borrowed from the Exploratorium’s Square Wheels book (thanks to master tinkerer Don Rathjen!)
Here are some supporting materials on my mentor and coauthor (Paul Doherty’s) website.