• Gilbert disproved, by experiment, many old mystical beliefs about magnetism - such as the notion that
lodestone, a naturally occurring magnetic ore, could cure headaches and the idea that a magnet could be
deactivated by rubbing it with garlic - and invented the technique of magnetizing pieces of metal using
lodestone.
• gave the names ‘north pole’ and ‘south pole’ to the two extremities of a bar magnet.
• nothing new was added to scientific knowledge of magnetism for two centuries, until the discovery of
electromagnetism in the 1820s and the subsequent work of Michael Faraday
• Gilbert realized that there was a distinction between electricity and magnetism (indeed, he coined the term
`electric` in this context)
• it was not until the 1730s that the French physicist Charles Du Fay (1698-1739) discovered that there are two
kinds of electric charge, dubbed ‘positive’ and ‘negative’, which behave in some ways like magnetic poles, with
like charges repelling one another and opposite charges attracting one another
• The double name came about because a fifteenth-century ancestor of Galileo, called Galileo Bonaiuti, became
such an important figure in society as an eminent physician and magistrate that the family changed their name to
Galilei in his honor
• Galileo`s father, was an accomplished professional musician who was keenly interested in mathematics and
musical theory.
• If Aristotle was right, heavy hailstones would have to be manufactured higher in a cloud than lighter hailstones
- exactly the right distance higher up so that, falling at a greater speed, they reached the ground alongside the
lighter hailstones formed at lower altitudes. It seemed rather unlikely to Galileo, and he delighted in pointing out
to his fellow students and the teachers at the university that a much simpler explanation is that all the hailstones
are made in the same place inside a cloud, so they all fall together at the same speed, whatever their weight.
• Court mathematician, Ostilio Ricci, was giving a lecture on mathematics to some students. Rather than go away
and come back later, Galileo sat in on the lecture and became fascinated by the subject - his first encounter with
mathematics proper, rather than mere arithmetic. He joined Ricci`s students on an informal basis and began to
study Euclid instead of his medical textbooks
• Vincenzio refused, on the seemingly reasonable grounds that there were plenty of jobs for doctors but very few
for mathematicians. Galileo just carried on studying mathematics
• timed the swing of the pendulum as the arc the chandelier moved over gradually decreased, using his pulse.
This led him to discover that the pendulum always took the same time to complete one swing, whether it was