A Lemon Battery Via 3D Printing

There are a whole bunch of high school science experiments out there that are useful for teaching students the basics of biology, physics, and chemistry. One of the classics is the lemon battery. [iqless] decided to have a play with the idea, and whipped up a little something for his students.

The basic lemon battery is remarkably simple. Lemon juice provides the electrolyte, while copper and and zinc act as electrodes. This battery won’t have a hope of charging your Tesla, but you might get enough juice to light an LED or small bulb (pun intended).

[iqless] considered jamming electrodes directly into lemons to be rather unsophisticated. Instead, an electrolyte tray was 3D printed. The tray can be filled with lemon juice (either hand-squeezed or straight from a bottle) and the tray has fixtures to hold copper pennies and zinc-plated machine screws to act as the electrodes. The tray allows several cells to be constructed and connected in series or parallel, giving yet further teaching opportunities.

It’s a fun twist on a classroom staple, and we think there are great possibilities here for further experimentation with alternative electrolytes and electrode materials. We’d also love to see a grown-up version with a large cascade of cells in series for lemon-based high voltage experiments, but that might be too much to ask. There’s great scope for using modern maker techniques in classroom science – we’ve discussed variations on the egg drop before. Video after the break.

Continue reading “A Lemon Battery Via 3D Printing”

Charging An Electric Supercar With Lemons, Kids, And The Sun

First things first: the tease on this video, that an electric supercar can be charged from a massive lemon battery array, is exactly that – a tease. Despite that, it makes for an interesting story and a great attempt to get kids exposed to science and engineering.

The story goes that [Mark] was approached by Volkswagen to help charge the batteries on their entry for the upcoming Pikes Peak International Hill Climb, the annual “Race to the Clouds” in Colorado. Racers are tortured by a 4,700′ (1,440 m) vertical climb over a 12.42 mile (20 km) course that features 156 switchback turns. Volkswagen’s entry is an electric supercar, and they sent [Mark] a portable battery cart to charge up the best way he saw fit.

Teaming up with [William Osman], the first attempt was a massive array of lemon cells, made with waterjet-cut strips of zinc and copper held in a plywood frame. Studded with 1,232 lemons, the battery performed just about as well as you’d expect it would.┬áPlan B was cute, and another of [Mark]’s attempts to pad his “Funnest Uncle Ever” score a bit. He devised a zip line with regenerative braking to charge a cordless drill battery, and then indirectly harvested the energy in the battery by turning it into lemonade for a bunch of kids.┬áThe sugared-up kids rode the zip line till the battery was charged.

That was still a drop in the bucket, though, so Plan C saw [Mark] install a large solar array on his roof; the tie-in here was that the lemon-powered kids got to design a cleaning system for the solar array. A weak link, to be sure, but the kids had fun, and we can’t deny that the car will at least be partially lemon-powered when it heads up the hill.

Continue reading “Charging An Electric Supercar With Lemons, Kids, And The Sun”

The Practical Potato Cell

Potato batteries, lemon batteries, they’re all good fun for the classroom — but is there a way of making them better? [Marcel Varallo] decided to give it a shot — and we gotta admit, it’s a pretty cool idea!

Normally for these fruit and vegetable batteries you poke some leads into the battery, connect it to a clock, and bob’s your uncle. But what if we made them resemble batteries? [Marcel] took some copper pipe, cut it down to size, and poked it through a potato. Now he had a potato-cored, copper tube. Stick a zinc nail in the middle, and you’ve got yourself a battery cell! Or as [Marcel] likes to put it.. a Mar-Cell. Or the more scientific term.. the Solanum tuberosum based electron differencer V1.0.

Each potato cell produces approximately 0.8V, so if you throw eight in series, you’ll have the equivalent of a 6V battery, just maybe not the same mAh rating.

For another cool way to demonstrate electricity to youngsters, we love this lemon battery hack — it’s actually quite elegant.