Title: Potato Battery

Aim: To find out whether potato generate electricity and could it be used to light up a LED.

Hypothesis

(1) Battery generate electricity through chemical reaction between two electrodes. Potato juice may cause a chemical reaction with the copper and zinc inserted into it to

produce electricity.

(2) Voltage increases by connecting batteries in series. If potato is able to generate electricity, its voltage would also be increased by connecting them in series.

(3) If there is enough voltage produced by the potato, it should be able to light up a LED.

Materials used : 4 potatoes, cables, strips of copper & strips of zinc (Electrode), Light Emitting Diode (LED), Digital Multimeter

I have carried out an experiment and found that the voltage generated across half a potato is about the same as the voltage generated across a whole potato as shown below.

Voltage generate across the whole potato reads 0.87V

Voltage generate across half a piece of potato reads 0.826V

In order to minimise the number of potato used, I have decided to use half a potato as per cell throughout the whole experiment.

Variables

Changed variable : The number of potato used.

Measured variable : The voltages across the number of potatoes

Controlled variable: The zinc and copper are placed about 5cm a part on each potato.

Procedures:

(1) Cut the 4 potatoes into half, each half piece of potato is used as per cell throughout the experiment.

(2) Insert a strip of copper and zinc (electrode) onto a potato. Place them about 5cm apart and make sure that they are not touching each other.

(3) Connect the positive terminal of the multimeter to the copper and the negative terminal to the zinc using cable (do not place it in opposite way or you will get a negative values)

(4) Number of potato is increased by connecting them in series

The voltage across the 2 halves and 3 halves were 1.596V and 2.390V.

I have increased a potato each time by connecting them in series. Voltage generated across different number of potato was taken as shown below

I have tabulated the the 8 readings and plotted a graph as shown below:

From the graph, I have observed that voltage increases as the number of potato increases.

I tried connecting a LED across 2 and 3 halves of potaoes but the electricity generated

was not enough to light up a LED.

Eventually, I used 4 halves potatoes and the electricity generated across was enough to light up a LED.

In order to see the results of the LED being lighted up brighter, I increased the number of potatoes as shown below:

The above photo shown that the more potatoes is used, the brirghter will be the LED

Conclusion:

From the above experiment, I can conclude that potato generates enough electricity to light up a LED. The more number of potato is used, the higher will be the voltage generated across it and therefore the brighter the LED.