A gold leaf electroscope is used to perform experiments involving static electricity - Leaving Cert Physics - Question 8 - 2010

A student would charge a plastic rod by rubbing it with a material such as fur. This process transfers electrons, giving the rod a negative charge.

The student would bring the charged rod close to the cap of the electroscope. This would cause the gold leaf to rise due to the induction effect, indicating that the rod is charged.

The SI unit of electric charge is the coulomb.

When the charged plastic rod is brought near small pieces of paper, it induces a charge in them. The side of the paper closest to the rod becomes oppositely charged and is attracted, while the far side remains neutral.

In the experiment, an electrode is placed in a dish filled with dielectric oil (such as castor oil or semolina). When a voltage is applied across the electrode, the surrounding electric field can be observed as field lines radiating from the electrode. A diagram should illustrate the electrode in the center, with lines indicating the direction of the electric field, directed away from positive to negative.

Another example of an inverse square law is Newton's law of universal gravitation, which states that the gravitational force between two masses is inversely proportional to the square of the distance between their centers.