🍋 Lemon Battery
Turn fruit into a power source and make a little LED glow!
🧰 What you need
- 3–4 fresh lemons (juicy ones work best)
- 3–4 galvanized (zinc-coated) nails
- 3–4 copper coins or short pieces of thick copper wire
- 5 alligator-clip wires
- 1 small red LED (red needs the least voltage)
- Optional: a multimeter to measure voltage
🔧 Let's build it!
- Roll each lemon on the table while pressing gently. This makes the inside extra juicy.
- Push one zinc nail and one copper piece into each lemon, about 2–3 cm apart. They must NOT touch inside the lemon.
- Use a clip wire to connect the copper of lemon 1 to the zinc nail of lemon 2. Keep going: copper to zinc, lemon to lemon. This is called connecting in series.
- You should now have one free zinc nail at one end and one free copper piece at the other end.
- Connect the free copper to the LED's longer leg (+) and the free zinc to the LED's shorter leg (−).
- Dim the lights and look closely. Your LED should glow! If not, flip the LED around or add another lemon.
- Bonus: use a multimeter to measure the voltage of one lemon, then of all of them together.
🔬 What's happening?
Zinc and copper are different metals, and they "want" electrons differently. The lemon juice is an acid that lets tiny charged particles move between the metals. Zinc gives up electrons, they travel through your wire and LED, and arrive at the copper. One lemon gives roughly 0.9 volts. That isn't enough for an LED, so we stack lemons in series and their voltages add up, just like stacking batteries in a flashlight!