Build yours at home · Build 005
Build a battery
What we're doing
Make a battery from a lemon and two different metals. The meter shows the small push it makes.
About 20 minutes.
Goes with these lessons
Extra experiment: not in a lesson yet. Needs a multimeter.
Get these parts
- A lemon (household)
- A piece of bare copper wire, and a galvanized (zinc-coated) nail (hardware store)
- A multimeter with clip-on probes (hardware or electronics store)
Keep it safe
Don't eat or drink anything used here. Wash hands afterwards.
Steps
- 1
Roll the lemon on the table, pressing down, to make it juicy.
- 2
Push the nail and the copper wire into the lemon, a finger apart. They mustn't touch.
- 3
Set the meter to DC volts. Clip the red probe to the copper and the black probe to the nail. It reads about 0.9 volts: a small push.
- 4
Swap the probes. The number turns negative: the push goes one way round.
- 5
Throw the lemon away and wash hands.
Talk while you build
- What do you predict when we change one metal?
- What happens when we swap the meter's leads?
More for grown-ups · printed parts
Optional equipment
Prints that make the build easier. None are required. Every build works with tape and clips.
Hackaday
A tray that holds pennies and zinc screws in lemon juice, with cells we can connect in series or parallel.
Not printed yet
Printables
Stack zinc washer, banana slice, copper washer. More layers, more voltage.
Not printed yet
Grown-up references
Make: Electronics — Learning by Discovery · Charles Platt Covers voltage and simple circuits, and includes making a battery.