Other+Scientists

Democritus
[] Summarize his theory of the atom.

Democtitus' theory of the atom was that everything is made up of them, making there be an infinite amount and kinds of atoms which are all different. He said that atoms are unbreakable, will always be in motion, and the only thing that lies between them is air. While studying the shapes of the atoms he found that the "solidness of the material corresponded to the shape of the atoms involved." By saying this he meant two alike characteristics go together when it comes to atoms. For example he said that "iron atoms are solid and strong with hooks that lock them into a solid." By saying this he was proving his theory that the two characteristics go together.

Who were his critics and what theories were postulated to challenge his?

A man who went against what Democritus had to say was Lucretius. Lucretius claimed that opposite atoms can still have a major effect. He said that through time even hard rocks can wear down when drops of water are placed onto them. Parmenides and Zeno were two other men who added onto what Democritus had said. Parmenides believed there was no movement within atoms, because there was no "void" which means there was no empty space, that Democritus claimed there was. Scientist, however, ignored Parmenides arguments because motion is always there, due to Newtons theory of "absolute space," and Einsteins theory of "relativity." Therefore Democritus' theory stayed to what he had said before.

James Chadwick [] James Chadwick Discovered the Neutron in 1932. It took a long time to discover because there was protons and electrons that would cancel but there was something throwing them off.

Louis DeBroglie [] Explain his contribution to the wave-particle duality theory.

Louis DeBroglie’s contribution to the wave-particle duality theory

In 1921, Albert Einstein demonstrated that electromagnetic wave has properties of matter in addition to waves. This is called the wave-particle duality theory, and this work earned him a Nobel Prize. Three years later, Louis Debroglie thought that since light has particle properties, like electrons, could those particles have wave- like properties, too? To find out, he combined (with algebra) Einstein’s iconic equation E=mc2 and Planck’s E=h n.

The result was: h=6.626068 × 10-34 J s

The wave length calculated is much, much smaller than a gamma ray, the shortest known wave length until this discovery. With the mass of the electron and the speed of the electron ( 105 m/s) and the wave length, it can orbit the nucleus about 3,000,000 time per second. In order to handle this problem, the electron must be treated as a wave. Robert Millikan [] What is Millikan’s major contribution?

He proposed the forumla for the charge of a single electron

Watch the video that animates the Oil Drop Experiment. Let’s pretend that you have to explain what happened in this experiment to a class of fourth graders. How did the experiment work and what did Millikan find out? You cannot use any big fancy words!!!


 * F**or the oil drop experiment Millikan took a closed cylinder and added on to that two metal plates (the one on top with a small hole in it so the oil could go down into the center of the cylinder), a perfume like bottle to lightly spray oil from, a battery pack to charge the metal plates positively and negatively and a microscope to look at the oil drops falling though the hole cut in the metal plates. He also had added an x-ray camera so he could inject the oil droplets with negative charges the one that did get injected fell faster than the one that were positively charged.

Erwin Schrodinger and Werner Heisenberg [] State Heisenberg’s Uncertainty Principle. -In 1927, Heisenberg stated that certain specific pairs of variables cannot be measured simultaneously with high accuracy. Most importantly he found out and showed that within an atom, it is possible to meaure the postion or momentum, of a particle such as a electron. It is not possible to measure them at the same time. -specific pairs of variables connot be measured simutaneously with high accuracy which includes atoms because it interferes with substantial degree being measure. But within the atom you can measure the position and momentum such as an electron. Explain Schrodinger’s contribution to the model of the atom. He made a equation that you can find the electrons 90% of the time around the nucleus. He also came up with a probability of finding the electron in a specific place around the nucleus. Find visuals that show what Schrodinger’s s, p, d, and f energy sublevels look like.