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Minor Versionm

by Suchitha Vishwa


The Voltaic cell was one of the first batteries to be invented and the principle behind its operation is still used in some modern batteries. A simple 'wet' cell consists of two metal plates separated by a liquid. Known as the electrolyte, this liquid serves as a channel for balancing the charge between the electrodes when the cell is being discharged.

    • Handle scissors with care

    • Do not ingest any of the materials

  1. Fill about 100ml of  water in the paper cup.
    • Fill about 100ml of water in the paper cup.

    • Add citric acid and stir vigorously with a spoon.

    • Keep adding salt till no more will dissolve in the solution.

    • Use sand paper to remove the enamel coating on the copper wire.

    • Cut the wire and the steel wire into 4 equal parts. 5cm each of the steel wire and about 25cm of copper wire. These will be the individual electrodes for each of the cells.

    • Using the scissors cut 4 rectangular pieces from the cloth bag, measuring about 8cm X 3.5cm each.

    • Now, with one of the rectangular pieces laid out flat on a table, place one cycle spoke along one of the long edges of the cloth piece.

      • Make sure there is about 1.5cm of the steel wire extending beyond the cloth. These will serve as a negative contact for the completed cell.

    • Roll the cloth around the wire tightly and then hold it at the bottom to keep it tight.

    • Now wind the copper wire around the cloth in a screw pattern. Start from the top leaving about 2cm of copper wire free to serve as the positive contact and wind downward.

    • Now cut the drinking straws into 4 pieces measuring 3.5 cm in length.

    • Then slide the cell you just wound into the straw taking care to leave the terminals outside. Make sure the terminals don't touch each other either.

    • Immerse the cell in salt water for about 30 seconds to a minute. Making sure that salt water seeps into the cell.

    • Using a voltmeter or a multi-meter set to voltage, check the voltage on each of the cells. The copper wire is the positive terminal and the steel wire is the negative terminal.

      • Each cell should be around 0.7V. Make sure the cell voltage is not below 0.55V, otherwise there will be insufficient voltage to light the LED.

    • Now connect the positive of one cell to the negative of the other, leaving only one set of terminals free.

    • Then proceed to connect the positive terminal of the LED (longer leg) to the free positive terminal and the negative to the negative terminal of the last cell in the series. This can be done with 2 pieces of electric (connecting) wire.

    • The led should now be illuminated.

    • If the LED does not glow, it could be caused by either, an improper connection between the cells or a short (positive and negative of the same cell are touching) on one of the cells.

Finish Line

Kailash NR

Member since: 05/02/2017

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