DISCOVERING MAGNETISM GREAT SCIENTISTS WHO STUDIED AND DISCOVERED THE NATURE OF MAGNETISM

Transcription

1 DISCOVERING MAGNETISM GREAT SCIENTISTS WHO STUDIED AND DISCOVERED THE NATURE OF MAGNETISM

2 WHAT IS MAGNETISM? To ancient people, magnetism must have seemed like magic. Thousands of years down the line, we understand what happens inside magnetic materials, how their atomic structure causes their magnetic properties, and howelectricity and magnetism are really just two sides of the same coin: electromagnetism. Once scientists would have said magnetism was the strange, invisible force of attraction between certain materials; today, we're more likely to define it as a force created by electric currents (themselves caused by moving electrons).

3 MAGNETISM: AN INVISIBLE FORCE?? Magnetism was first discovered in the ancient world, when people noticed that lodestones, naturally magnetized pieces of the mineral magnetite, could attract iron. [1] The word magnet comes from the Greek term μαγνῆτις λίθος magnētis lithos, [2] "the Magnesian stone, [3] lodestone." In ancient Greece, Aristotle attributed the first of what could be called a scientific discussion of magnetism to the philosopher Thales of Miletus, who lived from about 625 BC to about 545 BC

4 Gaius Plinius Secundus (23 AD 25 August 79 AD), better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian. Spending most of his spare time studying, writing or investigating natural and geographic phenomena in the field, he wrote an encyclopedic work, Naturalis Historia ("Natural History"), which became a model for all such works written subsequently. Pliny the Elder died on 25 August 79 AD. He was attempting the rescue by ship of a friend and his family from the eruption of Mount Vesuvius. The eruption had just destroyed the cities of Pompeii and Herculaneum. )

5 Tito Lucrecio Caro (99-55 a.c.). Latin philosopher and poet. He was born around 99 BC and died around 55 BC Do not just know data about his life: not known the place of birth, even perhaps in Campania. It seems that he was in Rome, where he met the theory of the nature of the things. Everything is made up of atoms, even magnets.

6 Alexander Neckam (sometimes spelled "Nequam") (September 8, , Hertfordshire, England), was an English theologian,philosopher, teacher, scientist, and geographer who helped to introduce the new scientific principles and Aristotelian logic of the twelfth century to scholars in England Besides being a theologian, Neckam is associated with the history of nautical science. His textbook De utensilibus ( On Instruments ) is the earliest known European writing to mention the magnetic compass, and De naturis rerum contains the earliest European references to the use of the magnet as a guide to seamen. These seem to be the earliest records outside of China (the Chinese encyclopaedist Shen Kua gave the first clear account of suspended magnetic compasses one hundred years earlier, in his 1088 book Meng ch'i pi t'an, Brush Talks from Dream Brook)

7 Willian Gilbert ( ) English physician, physicist and natural philosopher. One of his largest contributions was to fix the mistake of Thales of Miletus He made the difference between static electricity and magnetism clear. He coined the New Latin word electricus which would become the modern word electricity.

8 Charles François du Fay ( ) French Chemist He discovered two types/properties of electricity that he named vitreous and resinous. These are now called positive and negative

9 Hans Christian Oersted ( ) He was the man who discovered the link between electricity or electric currents and magnetism, or electromagntism. He was a Danish physicist and chemist who discovered that electric currents create magnetic fields, which was the first connection found between electricity and magnetism. He is still known today for Oersted's Law.

10 THIS IS THE MAGNETIC FIELD BETWEEN THE OPPOSITE POLES OF TWO BAR MAGNETS THAT STRONGLY ATTRACT ONE ANOTHER. WE CAN'T NORMALLY SEE MAGNETIC FIELDS, BUT IF YOU SPRINKLE IRON FILINGS (TINY BITS SHAVED OFF AN IRON BAR WITH A FILE) ONTO A PIECE OF PAPER AND HOLD IT ABOVE THE MAGNETS YOU CAN SEE THE FIELD UNDERNEATH. )