Make a Photon Flower That Lights Up When You Water It with Lemon Juice

Have you ever made a battery out of a lemon? If you poke a copper wire into a lemon and poke a zinc-coated nail in next to it, you can measure with a voltmeter that the lemon produces between 0.5 and 1 volt. The copper is the "cathode", or positive end of the battery, the zinc is the "anode", or negative end, and the lemon juice is the "electrolyte". This instructable shows you how to make an artificial flower in which each petal of the flower is like a lemon battery cell. When the petals are connected in series and moistened with lemon juice, an LED at the center of the flower lights up. This instructable builds on the ideas of Madaeon but uses a design that doesn't require soldering.

You will need:
- Eight zinc-coated nails.
- A paper towel cut into eight 1.5" x 1.5" patches.
- Uncoated copper wire.
- A cork.
- Lemon juice.
- An LED. This project works best with an LED that has a low forward voltage and low forward current. I used a 1.6v 1mA LED. Other LEDs may work but may require more cells to light up brightly.

See captions for details.

Step 1: Wrap the Petals

Roll a patch of paper towel around a zinc nail and wind a 12" copper wire on top of that. Leave a 4" tail of wire. Make eight of these.

Comments

[cocojen]

Just wondering if the wires need to be wrapped in the same direction around the nail and can the wires on the paper towel touch each other or do they need to be spaced?

[lclarkberg]

It doesn't matter how the wires are wrapped or if they are touching--the main thing is that there is a mass of copper covering the paper towel which is covering the nail. The wires here don't serve as inductors (such as electromagnetic coils in a motor) in any way, they just provide a surface area for electrons to pass through. You could just as easily use copper foil in place of the wires.

[rxj69]

I really want to try this project with my boys. But I have a question. What gauge is your copper wire? It looks quite fine. Where did you get it?

[Wyle_E]

Wire size isn't at all critical. You just want something stiff enough to stay wound around the cell, but not too heavy for the boys to wind without tools. If you can't find some scrap wire, Radio Shack sells "hookup wire", and hardware stores have doorbell wire.

[profeponcho]

Great project! Gonna try it w/my students! =)

[porcupinemamma]

Well how cool is that? Duh... VERY!

[madaeon]

Nice!

[marcellahella]

cool! voted

[lclarkberg]

Some things to try: copper foil (but make sure if it has glue on one side that the glue doesn't interfere), aluminum foil in place of zinc (actually it's the 5% magnesium in the aluminum alloy that provides the battery action), or aluminum cans (again it's the magnesium; also you'll have to sand off the interior and exterior coating).

[nox1468]

nice work! i want to try this with some more petal-like materials and see how it turns out.