Lemon Battery

Normally we plug something into an outlet or put batteries inside to get power, but did you know we can make electricity using lemons instead? When we drink lemon juice, the electrolytes help power our muscles and give our body power. However, when we stick a few common metals inside a lemon and create a circuit, the juice can power a light bulb! 

 MATERIALS:

  • 4 lemons

  • 4 zinc galvanized nails

  • 4 pennies

  • 5 alligator clips

  • Knife

  • LED light bulb

TIME ESTIMATED:

20 minutes

DIRECTIONS: 

  1. Ask an adult to cut a penny sized slit closer to one end of the lemon.

  2. Repeat this for all 4 lemons.

  3. Halfway insert a penny into the slit of each lemon.

  4. Next, push a zinc galvanized nail into the other end of each lemon. 

  5. Now, use the alligator clips to connect the nail of one lemon to the penny of a different lemon.

  6. Repeat this until all the lemons are connected. There should be an open nail on one end and an open penny on the other when you’re done.

  7. Connect one alligator clip to the open nail.

  8. Connect one alligator clip to the open penny.

  9. Finally, touch the loose ends of the two alligator clips to the metal base of the light bulb. Watch what happens!

THINK LIKE A SCIENTIST!

  1. How does the lemon work as a battery? Why does it light up the bulb?

  2. Why do we place the penny and the zinc nail on opposite ends of the lemons?

HOW DOES IT WORK? 

Electricity is created when electrons move from atom to atom, producing a flow of electric current. When these atoms gain or lose an electron, they become charged and are called ions. Lemon juice has lots of electrolytes (the liquid form of ions), so it's great at carrying electricity. We call this a conductor, or a substance that electricity can flow through. Regular batteries also contain electrolytes, and they have positive and negative ends as well, which we created using pennies and zinc nails. The copper penny acts as the positive end (the cathode) while the galvanized zinc nail acts as the negative end (the anode). The zinc reacts with the lemon juice, creating positive zinc ions and loose electrons. Recall that electrons are negatively charged, so they move across the lemon towards the positively charged copper penny. Just like that, we created electricity! Additionally, by connecting multiple lemons together, we created a circuit. A single lemon wouldn’t have been powerful enough to turn on our light, so we linked four together to increase the power output.

FURTHER EXPLORATION: 

When we think of electricity, we typically think of things in our homes, such as computers and lights. However, electric transportation has become an extremely important field in science. Consider mechanical engineers, who are the scientists that develop electric cars. They design vehicles that use extremely efficient and powerful batteries to power the motor instead of gasoline. In our experiment, the force of the electrical current (or voltage) was very small— around 3.5 volts for four lemons. In comparison, the average electric car uses a 400 volt battery for power. That said, these scientists are always looking for ways to pack more power into smaller spaces, as well as increasing the safety of these high-voltage batteries.

Anticipated COncerns

Have an adult handle the knife and help with the cutting. Also, don’t eat or drink the lemons after the experiment. The metal contaminated them!

Looking for more fun at-home STEM activities for your young scientist? Check out our workbook full of exciting science experiments and empowering activities! 

Learn more and purchase today!