This is a brilliant activity for Harvest celebrations – an up-front demo for All Age Worship or school assemblies, or a try-it-yourself for youth groups, Messy Church, Light Party or classrooms.
We’re going to think about the wonder we can find when we look a little deeper into the world around us – by using potatoes to power a string of fairy lights!
Here are some linked ‘Spud’ resources.
One P’tater, Two P’tater: a sketch about a sad potato called Spud, who finds out he is extraordinary
P’tater Prayers: a mediation seeing the extraordinary inside the ordinary, using a potato, and some quirky intercessions linked with the sketch.
Getting your Spud Power
You will need:
- ‘croc clip’ test leads
- or lengths of wire plus pegs or bulldog clips
- galvanised nails – these are covered with a layer of zinc, which is one of the metals that makes the cell work
- 2p coins (try to get shiny ones) – these are coated in copper, which is the other metal
- multimeter (optional)
- string of LED lights (the type powered by two AA batteries)
- or individual LEDs
What to do:
If your coins are grubby, clean them beforehand so that you get good connections. You could soak them in vinegar overnight, or just give them a good scrub down with normal household cleaning products.
If you are using pieces of wire, you will need to strip about 1cm of insulation off each end. You can do that by twisting it between the blades of slightly open scissors. This makes a notch in the plastic and you can pull the end off. Twist the bare wires together.
If you are using individual LEDs, you can join a few in series by twisting the short leg of one LED to the long leg of another. You should have one spare long leg and one spare short leg at the ends.
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If you are using LED fairy lights, remove the batteries and make sure the switch (if there is one) is set to on.
Cut the potatoes into chunks. Each chunk produces power. You can boil them for 5-10 mins to get more power, but I used mine raw.
In each chunk of potato, put a zinc-plated nail at one side and a copper coin at the other. Make sure that they are not touching inside.
Line up the potatoes so that the metals alternate and join them in series with the croc clips or with lengths of wire and clips.
It should go: copper-spud-zinc-wire-copper-spud-zinc-wire-copper-spud-zinc and so on. There should be one spare nail at one end and one spare coin at the other. (In this picture I’ve connected the spare coin and nail to small clock.)
If you want to check how much electricity you are getting connect the test leads of your multimeter to the spare coin and the spare nail. If the voltage shows negative, swap the leads. With six chunks of potato you might get up to 3v. Or you might not.
Use two more pieces of wire to join the copper and zinc ends of your potato battery to the LEDs. If they don’t light up, try them the other way around. For the string of fairy lights, connect your spud-battery to the spring and flat terminals of the battery pack, the ones near the switch.
Ta da! You should have working lights! If they are dim, you can try getting more power by adding more spuds in series (to get more volts) or in parallel (to get more amps). Click the diagrams below for more information on this. If you are in a brightly-lit room, put the lights in a box to make them show up more.
To think about
There’s more going on than you think inside a potato. Who would have guessed that the humble spud could produce electricity? If you wired up enough of these you could even charge your phone! Honestly, you could. (OK, it would take a whole sackful and I don’t know that I’d bother, but you could.)
It’s a reminder that we often don’t know what’s going on inside. We make assumptions based on what the outside looks like, but there could be so much more going on that we never imagined.
And if it’s like that with a humble spud, how much more with a human!
The Bible teaches us that humans are breathed into life with God’s breath and made in God’s image. I am made in God’s image – wow! That doesn’t mean that God is white, female, 5′ 10″ and has frizzy hair. It means that as well as being built out of star-stuff (you know that the atoms that form your body came from stars, yes?) as well as being built out of star-stuff, we all reflect a little bit of God, too.
The loyalty of a friend – that’s a reflection of God’s loyalty. The warmth of a hug – that’s a reflection of God’s warmth. The joy of running into huge pile of leaves and throwing them everywhere – that’s a reflection of God’s joy (although the gardener who just swept them up might not agree).
What can you see in the people around you today? And what might others see in you?
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