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

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by lclarkberg

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Intro: 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.

STEP 2: Assemble the Flower

Push the nails into the cork radially. (If you have trouble, you can drill small holes in the cork first.) Next connect the petal battery cells in series by connecting the positive (copper) end of one cell to the negative (zinc) end of the next cell. To do this, connect a copper wire tail to its neighboring nail's head. Be sure to make a good connection: wrap the wire tightly at least four times around the nail. Continue connecting tails to heads. However, don't connect the last tail! Doing so would cause a "short circuit" that could damage your battery. The last tail and nail head will be connected to the LED in the next step.

STEP 3: Connect the LED

LEDs need to be connected with the correct polarity; that is, connected in a circuit with positive-to-positive and negative-to-negative wiring. Look carefully at your LED and you will see that one lead is longer than the other. This is the positive lead. Connect it to the positive lead of your battery, which is the last (unconnected) copper tail. Twist the positive lead of the LED onto the last tail of your battery. Be sure to intertwine the leads so that they have a good connection.

Twist a 2" length of copper wire around the LED's negative lead, and wrap the other end around the remaining unconnected nail head (which is your battery's negative connection).

STEP 4: Light the Flower

The moment of truth! Place a drop of lemon juice on each petal's paper towel. When all of the petals are moistened, the LED should light. Yay!

If the LED doesn't light, check that all of the connections are good. Make sure that on each petal, the copper wrapped around the paper towel is not touching the copper wrapped around the nail head.

The LED should stay lit for half an hour or so until the paper towels dry out. You can light it up again simply by adding more lemon juice.

Try adding a stem, leaves, and a flower pot. Try using other kinds of metal. Try making the petals out of metal foil instead of wire. Experiment! Have fun!

22 Comments

yutazz 7 years ago

what can be n hypothesis and a aim for this experiment?

yutazz 7 years ago

what can be a hypothesis and aim for this experiment?

Melody8675 8 years ago

Is there any other light bulb we can use to make this project work?

angryrobot17 11 years ago

if you attach a wire to all the petals and the soil can you actually "water" it?

yrockzz 11 years ago

cool idea,...... :)

cocojen 11 years ago

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 11 years ago

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 12 years ago

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 12 years ago

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 12 years ago

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