Making a Leyden jar

"Leyden jar" is the name by which the first capacitor was known, named after the city in Holland where it was invented. Its accidental discovery by Dutch professor Pieter van Musschenbroek is a fascinating story of scientific serendipity.

In this article, we will see how you can easily make a Leyden jar using materials lying around in the kitchen. One good enough to give shocks and produce visible sparks.

Materials needed
  • a small plastic container with a lid (I used an ice cream cup)
  • aluminium foil or adhesive aluminium tape
  • a steel fork
  • a PVC pipe and a woollen cloth for charging
  1. Stick aluminium foil or tape all around the plastic container, and on its bottom. This will act as the outer conductor of the capacitor.
  2. Make a hole in the lid of the container. The fork should pass through the hole and stay supported when the lid is fixed on the container.
  3. Fill two-thirds of the container with water. Take care to see that the lid or the rim of the container do not get wet, as that would cause the charges to leak away.
  4. Close the container with the lid with the fork running through it.
Charging the Leyden Jar

Keep the Leyden jar on the ground. Rub a PVC pipe on wool and pass it lengthwise near the fork. In dry weather, you can hear the crackling sound of electric charge getting transferred from the PVC pipe to the Leyden jar through the fork. Repeat this 10-15 times to sufficiently charge the Leyden jar.

If you now touch the fork, you will receive a moderate electric shock. Strong enough to make you jump in surprise if it is the first time, but completely safe! To see sparks without having to subject yourself to the inconvenience of the shock, you can use a steel spoon to touch the fork, with one end of the spoon touching the ground.

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