Scientists, models, and laws Flashcards
Tycho Brahe
-A Danish nobleman and astronomer in 1600’s.
-Imperial mathematician for the king of bohemia.
-cataloged astronomical data for over 1000 stars.
-predicted a conjunction using Copernicus’ heliocentric model. -observed something he called a supernova (a new star) which was evidence that starts were not unchanging
Johannes Kepler
-German astronomer and mathematician.
-developed three laws of planetary motion that were published in 1619.
-was the first to hypothesize that the sun exerted force on the earth.
-made important discoveries about geometry, optics and principles of gravity.
Galileo
-an Italian mathematician in the early 1600s
-published The Starry Messenger in 1610
-improved the telescope
-used his newly improved telescope to discover craters on the moon and sunspots
-important because this showed that the heavenly bodies are not perfect and unchanging.
-discovered 4 moons around Jupiter
- conflicted with the idea that there were 7 heavenly bodies
-put on trial for heresy in 1633
-put on house arrest
Nicolaus Copernicus
-Polish astronomer, early 1500’s
-First proposed detailed mathematical heliocentric model of the heavens and published a book about it
-Copernican revolution: change in thinking from a geocentric to heliocentric model
Isaac Newton
-An English mathematician in the late 1600s
-developed calculus
-developed his three laws of motion
-developed an entire theory of optics and light.
-formulated the law of unviersal gravitation
-published Principia Mathematica in 1687
Newton’s first law
An object at rest remains at rest and an object in motion continues moving in a straight line at a constant speed, unless it is compelled to change that state by forces acting on it
Newton’s second law
The acceleration of an object is proportional to the force acting on it, or
a=F/m
where a is the acceleration of the object (m/s^2), F is the net force on the object in newtons (N), and m is the object’s mass (kg)
Newton’s third law
for every action force, there is an equal and opposite reaction force.
Einstein
-German physicist in the early 1900s
-introduced the general theory of relativity which was published in 1915 (E=mc^2)
Ptolomeic Model
- There are 7 heavenly bodies
- All of the heavenly bodies move in perfectly circular orbits. There are 9 spheres.
- All the heavenly bodies are perfectly spherical
- Geocentric
- Corruption and change only exist on earth. All of the heavenly bodies are perfect and unchanging
- All of the heavenly bodies and stars revolve around the earth every 24 hours
- Epicycles used to explain the motions of the plants in relation to the stars
Kepler’s first Law of Planetary Motion
Each of the planetary orbits is an ellipse with the sun at one focus
The 9 spheres
-moon
-Mercury
-Venus
-sun
-Mars
-Jupiter
-Saturn
-the Firmament (the stars arranged in their constellations)
-the Primum Mobile (the “First Mover”, orbits the earth every 24 hours and drags the other spheres with it)
-the Empyreon: where the gods live
Newton’s equation for universal gravitation
F=Gm1m2/d^2
J. J. Thompson
-English scientist
-Executed the cathode ray experiment in 1897 in which he placed electrodes in a sealed vacuum tube which shoots a negatively charged cathode ray from one electrode to another
-A cathode ray is made of electrons but he did not know that
-he discovered that when magnetic coils were put on the side of the tube the ray deflected.
-Thompson theorized that the ray was made of negatively charged particles.
-he developed an atomic model that envisioned atoms as tiny clouds of massless, positive charge sprinkled with thousands of negatively charged electrons
Robert Millikan
-American Scientist
-executed the oild drop experiment in 1911
-he did some complicated math and was able to figure out the individual charge of one electron.
