Handouts for Building Utilitites 2

1. Electricity A physical entity associated with the atomic structure of matter which occurs in polar forms (positive and negative) and which are separable by expenditure of energy; an invisible energy capable of moving 186,000 miles per second; the science dealing with the physical phenomena arising from the existence and interaction of electric charges. Electrons are negatively "charged particles while protons are positively charged particles.

2. a very short... Historical Background

3. In 500's B.C., Thales a Greek philosopher of about this time, observed that amber , a stone-like substance attracted small bits of straw after being rubbed with cloth. In the 300's - B.C., the Greek philosopher Plato mentioned this property of amber in one of his works.

4. In A.D. 1551, Jerome Cardan, an Italian mathematician distinguished between the properties of amber and those of magnetic black rock called loadstone . Cardan realized that amber attracted many light objects, but loadstone attracted only iron.

5. In 1600, William Gilbert , a doctor of Queen Elizabeth I of England, discovered that such materials as diamonds, glass, sulphur and wax behaved like amber. He called these materials electrics , a term based on electrum , the Latin word for amber. In 1646, another English doctor, Sir Thomas Browne , devised the word electricity .

18. FORMULA: OHM’S LAW I (amp) = V (volts) R (ohms) The current – I , that will flow in a d-c circuit is directly proportional to the voltage – V , and inversely proportional to the resistance - R , of the circuit