Leyden Jar Experiment

Feel the power of stored electricity
A simple static electricity experiment with everyday materials

1. What is a Leyden jar?

The Leyden jar is an electrical experiment device invented in the 18th century at Leyden University in the Netherlands.
By placing metal layers on both sides of an insulating material such as glass or plastic, static electricity can be stored and then discharged.
It is considered the prototype of the modern capacitor.

2. Safety precautions

Since a Leyden jar can store a strong charge, it can be dangerous if handled incorrectly. Do not perform this experiment if you:

• Have heart disease
• Use medical devices such as pacemakers
• Are pregnant
• Are a small child (infants or lower elementary grades)
• Have chronic conditions such as epilepsy

Always perform the experiment under adult supervision.

3. Materials

• 2 plastic cups
• Aluminum foil
• A strip of aluminum foil (to connect the two cups, shaped like “ears”)
• PVC pipe (available at hardware stores)
• Tissue paper (for rubbing the PVC pipe to generate static electricity)

4. How to make it

1. Take two plastic cups and wrap aluminum foil around the outside of each.
2. Insert a narrow strip of aluminum foil between the two cups, with the ends sticking out like “ears” and overlapping each other.
   → These “ears” act as the discharge points.
3. The Leyden jar is now ready.

5. How to do the experiment

1. Rub the PVC pipe with tissue paper to generate static electricity.
2. Bring the charged PVC pipe close to the aluminum foil “ears.”
3. Repeat several times—electricity will gradually accumulate in the jar.
4. When you bring your finger or a metal object close to the ears, a spark will jump with a “click.”

6. Summary

With just plastic cups, aluminum foil, and a PVC pipe, you can easily make a Leyden jar.
Although the structure is simple, it is a fascinating device that lets you experience how electricity can be stored and discharged, just like in a modern capacitor.