For our first assignment in Design Frontiers in Biology and Materiality we were asked to recreate a science fair project from our childhood. Besides a project on dams back in 3rd grade, my most memorable science experiments came from my undergraduate neuroscience labs. Probably the coolest was when we embedded electrodes into a cockroach leg to read nerve impulses generated from tickling its hairs, but given the overhead in hardware isn’t a feasible option for recreating in class.

So instead I’m going to revisit playing with lemon batteries, something I had a go round with a few semesters ago.

Making lemon batteries is fun. It makes you wonder what other solution and materials might serve as an electricity source? As a result of two events over the last week —- the adoption of my new puppy Teddy and a snowfall —- I’ve spent a considerable amount of time outside and have noticed an abundance of two solutions that I have a hunch might substitute for lemon juice: pee and salty snow melt.

Using copper scrubbers and aluminum foil as electrodes, I recorded the voltage generated from a single circuit of each of these solutions:

I’m intrigued by the fact that pee works; further tests could check the effects of temperature, concentration, and volume on voltage as well as using different metals as electrodes. In researching lemon battery variations I came across a few configurations that work effectively for a decent amount of time (a few hours) using very little liquid in combination with joule thiefs.

If enough energy can be converted, a few pee-activated/powered applications that come to mind are:

• a security camera to capture those who do not curb their pets
• embedded sidewalk/curb/building lighting
• self-powered auto-flush toilets
• eco-friendly camping batteries