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Oct 27, 1000
Democritus
Democritus was born in the year 500b.c.
Democritus thought that all matter consisted extremely smaller particles that could NOT be divided.
They got in groups with peope with similar questions and answers and just made up their theories. -
Dec 30, 1000
Aristotle
(322 b.c.)
All substances were built up from only 4 elements; Earth, Fire, Air, and Water.
He made a model of the elements, and beside them he would put like hot, dry, cold, and wet. They would go by the proper element though, not just in random order. -
John Dalton
He thought that all matter was made up of individual particles called atoms, which cant be divided.
How: He made these wooden spheres, that were used to represent the elements. -
Thomas Edison
Invented lightbulb
How: Using lower current electricity, a small carbonized filament, and an improved vacuum inside the globe, he was able to produce a reliable, long-lasting source of light. -
Rutherford
Discoved that uranium emits fast-moving particles that have a positive charge.
He hypothosized that the mass and charge at any location in gold would be to small to change the path of an alpha particle. -
Hantaro Nagaoka
Suggests that an atom has a central nucleus.
How- Because the eletrons move around it, like the ring would of Saturn. -
Ernest Marsden
The sceen around the gold (see in pic) was made of a material that produced a flash of light when stuck by a fast-moving alpha particle.
By observing the flash he could figure out the path of an alpha particle after it passed through the gold. -
Niels Bohr
The electrons move in spherical orbits at fixed distances to form the nucleus.
How- Electrons traveling in orbits around the atom's nucleus the chem. properties of each element. -
J. J. Thomson
He used electric current to learn more about atoms.
Thomson used a sealed tube of gas in his experiments, He also put a metal disk on each side of the tube (2 disks), one pos. and one neg. and inside the tube he had a glowing beam. At the bottom he had a energy source. -
Louis de Broglie
Proposes that moving particlesclike electrons have some properties of waves.
How- Because you can measure the energy released when the electron goes from a high level of energy to a low level of energy, making what looks like a wave-like effect. -
James Chadwick
Designed experiments to prove that nuetrons existed.
Concluded that the particle he produced were neutral because a charged object did NOT deflect their paths. -
Albert Einstein
He came up with the theory of e=mc2
How: He made it possible to know that a very small amount of mass can be converted into a huge amount of energy. -
Erwin Schrodinger
Came up with electron cloud, which a visual model of the probable locations of electrons in an atom.
How- He figured this out by developing some mathmatical equations the descibe the motions (the movements), of electrons in atoms.
