In the Middle Ages, scholars decided truth based on the Bible or from Greek or Roman texts.
While Ptolemy was wrong, a positive consequence of his work was that it allowed stargazers and astrologers to track the planets with greater precision
This is commonly known as the GEOCENTRIC view where a motionless Earth is at the center of the universe while the moon, sun, planets, and stars revolve around the Earth.
Ancient astronomers also believed the Earth was composed of “heavy” elements while the celestial bodies were composed of completely different substances and thus were weightless, allowing them to orbit the Earth.
Using a telescope which he refined, he viewed the moon with all of it’s irregularities and stated that the moon is NOT a luminous object but is actually made of earth-like substances.
Galileo’s greatest achievement was the elaboration and consolidation of the experimental method ; rather than speculate about what might or should happen, he conducted controlled experiments to find out what actually did happen.
Using experiments, Galileo formulated the law of inertia stating that rest is NOT the natural state of objects.
Galileo in 1591, according to the story, dropped a 10-pound and a 1-pound weight simultaneously from the top of the Leaning Tower of Pisa.
Galileo showed that despite all previous speculation on the subject two bodies of different weights, when allowance was made for differences in air resistance due to differences of size or shape, struck the ground at the same time.
Galileo was put on trial and condemned by the Catholic Church because his discoveries contradicted scripture.
He was finally absolved by Pope John Paul II in 1992.
What does an apple have to do with gravity? Ac-cording to George Stukeley, Newton’s biographer and friend, Newton was sitting in the shade of an apple tree when an apple fell nearby. Newton began to wonder why apples always fall to the ground. Why don’t they fall sideways or up? Newton reasoned that the earth must have a power that draws objects to it. That was the beginning of the law of gravity.
Boyle defined the term element in 1661 as " . . . certain primitive and simple, or perfectly unmingled bodies; which not being made of any other bodies, or of one another, are the ingredients of which all those called perfectly mixt bodies are immediately compounded, and into which they are ultimately resolved."
Although Boyle's chief scientific interest was chemistry, he developed a brilliant series of experiments in which he used an air pump to create a vacuum. He also developed what later became known as "Boyle's law" that the volume of a gas varies inversely with pressure.
Developed theory of blood circulation (the heart pumps blood through the body)
This illustration depicts one of William Harvey's experiments in his On the Circulation of the Blood (1628). Venal valves had already been discovered, but here Harvey shows that venal blood flows only toward the heart. He ligatured an arm to make obvious the veins and their valves, then pressed blood away from the heart and showed that the vein would remain empty because blocked by the valve.