1600 – Versorium Electroscope – William Gilbert
In 1600 William Gilbert, the queen physician, published a book called De Magnete (Latin for “On the Magnet”) . It became the standard for magnetism and electricity. He developed a tool to detect electric charges (electroscope), which he called a versorium. It consisted of a needle on a pivot. He was also to use the term, in Latin, for electric force. He was also the first to realize that the earth was a giant magnet.
Experiment – Versorium
- aluminum foil (½ x 3 inches)
- Styrofoam cup
- A sharpened pencil or stick
- hair or fur
- A blown up balloon
- Fold the aluminum foil in half along the long side.
- Trim the ends to point at the fold
- Carefully, so you don’t poke yourself, from the inside of the cup, poke the pencil through the middle of the bottom of the cup.
- Stand the cup upside down with the pencil sticking up.
- Place the foil on the pencil, suck that is balances. You may want to carefully push down on the foil to make a dimple in the foil
- Rub the balloon on the hair and slowly move the area of the balloon that was rubbed near the soda straw.
- Write down your observations.
The balloon acquires extra electrons from the hair. When the balloon is placed near the straw, it negative charge on the balloon force the electrons away from the straw, making it positively charged.