DIT Fruit Battery Project is a science proper classic, and a great addition to a classroom lesson plan. It comes with everything needed to experiment with green energy.Features: Durable, Easy to Operate BioEnergy Experiment, Safe Great for classroom science power generation experiment. Easy to learn, exercise your children's practical skills.Instruction: Take 4 Lemons(other fruits like Apple, Pear, Potato). Insert 2 metal plates (one copper, one zinc) into each of them, connect the copper plate of lemon to the zinc plate of another lemon with wires. Then, connect the wire from the copper plate of the first lemon to the long terminal(+) of the LED (light-emitting diode). Also, connect the wire from the zinc plate of the last lemon to the short terminal(-) of LED. You will find that the LED grows! Reference voltage: Pear:0.95 Apple: 0.96 Potato: 0.6 Lemon: 0.99