… and how the very first electrical demonstration can be performed using materials found in every home.

Human knowledge of electricity began with lightning, electric fish and amber.

Lightning

Prehistoric people observed lightning in the sky during storms. It made a bright light and a powerful noise. It could kill people and animals. It sometimes struck trees causing fire. It was once thought to be fire from the sky. It is now known that lightning is electrical.

Electric Fish

There are several types of fish and eels that can sting a person in a way that causes numbness in the area of the sting, but does not cause a wound. These creatures were known in prehistoric times but not understood. We now know that they have a special defensive organ that generates electricity.

Amber and The Very First Electrical Experiment

Amber is resin from trees that has solidified over time. It looks and feels like hard plastic. It was gathered and saved by ancient people for decorative objects and jewelry purposes. Some pieces of amber have insects trapped inside.

Ancient people discovered that, after amber is rubbed with animal fur, it has the power to attract light materials such as dust and small feathers (down). This was the very first electrical experiment.

The ancient Greeks called amber “electrum” after their name for the sun, “elector.” Thales of Miletus, one of the seven wise men of Ancient Greece was said to have believed that amber must contain life to have the power to move things. We know now that the force of amber is due to static electricity. William Gilbert gave us the word electricity by his use of the Latin word electricus to describe electrostatic phenomena as “amber-like.”

Electrical Charge

All matter is composed of atoms. Atoms are composed of electrons, protons and neutrons. Electrons have a negative electrical charge, protons a positive charge and neutrons no charge. The protons and neutrons are tightly bound together to form the nucleus or center of the atom. The electrons are less tightly bound. The number of protons it an atom determines the atomic number and identity of the chemical element that it forms. Element number 1, Hydrogen has one proton. Element number 92 is Uranium with 92 protons.

Atoms in their “normal” state have an equal number of protons and electrons, so their positive and negative charges are balanced. That means that “normal” materials have no electrical charge. However, friction often causes electrons to transfer from one material to another. That is called the triboelectric effect. Some materials hold onto electrons more tightly than others. Amber holds onto electrons more tightly than cloth or animal fur, so when it is rubbed with those materials it tends to accumulate extra electrons and become negatively charged. Feathers, pieces of hair, dry skin and other materials that make dust tend to leave electrons behind when they are separated from there origin. That gives them a positive electrical charge. That is why amber that has been rubbed by fur attracts dust and small feathers.

Triboelectric Series

The triboelectric series shows the relative tendencies of materials to become positively or negatively charged by friction. Rubbing together two materials that are far apart on this table results in the highest level of electrostatic charge.

Electrostatic Experiment

The first two of the following pictures re-create the ancient experience of picking something up using amber that has been rubbed by animal fur. The third picture shows how anyone can re-create this experience by rubbing plastic with cloth.

A piece of amber on rabbit fur