Spark the Conversation

Spark Science: Lemon Powered Battery

September 22, 2017
Posted By: TELUS Spark

When live gives you lemons, forget the lemonade. Here's how you can take those citrus fruits and use them as a battery to complete an energy circuit!

Materials:

  • 5 Lemons
  • 6 Alligator clips (Digiwave Jumper Test Lead Cable) [Walmart]
  • 1 Mini LED light [Home Depot]
  • 5 Galvanized zinc nails [Home Depot]
  • 5 Copper pennies or copper sheets (If Canadian Pennies, make sure it is dated before 1982) 

Step 1:

Squeeze and roll the lemon to loosen the pulp. 

Step 2:

Using a knife, make inserts into the lemon big enough for one copper penny.

Step 3:

Take one Zinc nail and place it into the lemon on the other side of the penny (make sure it’s not touching the copper penny).

Step 4:

Connect one end of the alligator clip to the zinc nail (negative) and the other end to the copper penny on the second lemon (positive). Do this until all lemons are connected.

Step 5:

Connect the remaining ends of the alligator wire to each end of the LED light.

Challenge

Try different metals and fruits! Can they all generate energy the same way?

As we know, energy cannot be created or destroyed, but it can be transformed into something else. You can think of a battery like a storage room. It holds a lot of chemical energy, which can be TRANSFORMED into electrical energy.

Chemical energy - > Electrical energy -> Light energy

Batteries are made up of 3 major components: two electrodes and one electrolyte:

  1. Cathode (Copper Penny, Positive)
  2. Anode (Zinc Nail, Negative)
  3. Electrolyte (Lemon, Ionic Solution)

An electrode allows electricity to leave or enter an object. The zinc nail and copper penny will act as electrodes.

An electrolyte allows electric conductivity and It can be a base, salt, or in this case, an acid from our lemons!

Electricity is the flow of electrons.

When the zinc comes in contact with the lemon juice the acid starts to oxidize. That means the zinc is losing electrons. The copper undergoes a reduction reaction as it gains those electrons. Throw an LED light into the mix, and you’ve got a completed energy circuit and a really cool SCIENCE PROJECT!

Tips & Tricks

"It didn’t work for me!"

Let’s think about different variables as to why this experiment didn’t work

Pennies - Canadian pennies dated after 1982 have a lower concentration of copper. Try finding older pennies or use copper sheets as an alternative.

Lemons - Did you use enough lemons? Try using more or less and see if that changes the experiment.

LED Light - LED lights also have negative and positive charges. In order to light it, it needs to be following the energy circuit flow. Try switching the direction of the alligator clips to the LED lights.

Nails - The nails used must contain zinc. Make sure they are galvanized.