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460 BCE
Democritus
Who? Democritus Is Believed to have been born around 460 BCE in Abdera, where he was raised and lived out his life.
What? Democritus thought that instead of atoms just going in directions, they are actually orderly.
Where? Abdera, a municipality in Greece.
When? Thought to be a little after 460 BCE.
Why? Because he Hypothesized that if atoms were not orderly, then the universe would be unorganized as well. -
Law of Conservation of Mass
Who? Antoine Lavoisier was the physicist that brought the idea to life, even though the idea was recorded back to a long time ago.
What? The Law of Conservation of Mass, is the idea that the amount of matter is always the same, and it never changes. “Matter cannot be created or destroyed,” (Mrs. Heinz).
Were? In France
When? Around 1789
Why? People had already said this was possible, all Antoine Lavoisier had to do was prove to the world that it was true -
John Dalton
Who? John Dalton grew up and helped his older brother with teaching at his older brother's school.
What? He argued that each element had a different atom. He agreed with Democritus and his model.
Were? He was born and taught in Eaglesfield, England
When? Between September 5, 1766, and July 27, 1844
Why? Because he was studying meteorology and was believed that air was a mixture and not a compound. -
Dmitri Mendeleev
Who? Dmitri Mendeleev was a Russian teacher for a while, and then at some other universities.
What? While Dmitri was writing he found similarities in Atomic weights of atoms. he was able to figure out a order and organized the known elements based on his knoledge. He also was able to predict new elements.
Were? Russia
When? Mid to late 1800s
Why? Because he could not find a textbook that he liked so he made one -
Cathode-Ray Tube
Who? Heinrich Geissler, Julius Plucker, Sir William Crookes, Karl Ferdinand Braun, Vladimir Kosma Zworykin, Allen B. Du Mont
What? The Cathode-Ray Tube has a combination of electron guns that shoot a multi-colored beam down a tube containing a vacuum
Where? Some contributions were made in Germany and England and some other places.
When? From 1855 to 1931.
Why? Cathode-Ray tube was used in televisions until they were outdated by LCD’s -
Electron Cloud Model
Who? Erwin Schrodinger was the man behind the idea
What? The Electron Cloud Model was a model that suggested that electrons don't move around the nucleus in a set path, but instead they would move all over.
Were? Ohio and California.
When? 20th century.
Why? Because he thought that you could only guess on the location of the electrons -
Robert Millikan
Who? Robert Millikan was an American Physicist
What? He won a nobel prize for showing how different charges affect different particles. He used a container with two plates, on positively charged. And the other negatively charged, and using oil droplets to show that particles are affected by the charges around them.
Were? In The United States, but mostly in Ohio, and California.
When? Early 1900’s
Why? Because he wanted to show the effect of the charge of the particles. -
Rutherford Model
Who? Stated by a New Zealand physicist by the name of, Ernest Rutherford
What? Showed a positive core (called a nucleus) around which, really light and small negatively charged particles called electrons), mush like the planets around the sun.
Were? In New Zealand
When? 1911
Why? Because he wanted to show that electrons were not just thrown into the center, but more orderly placed. -
Erwin Schrodinger
Who? Erwin Schrodinger was a Australian Physicist
What? He wrote the basic mechanics for the atom indirectly
Where? The University of Zurich
When? Around 1926
Why? He had ideas that added onto other ideas, for example; Louis de Broglie. -
Plum Pudding Model
Who? J.J. Thompson
What? He developed a model that showed that the atom was made of more than one different parts that were somewhat separable. One of these parts are electrons called (electrons) spread out within another part, an area of positive charge.
Where? In england
When? Late 19th century to early 20th century
Why? Because he thought that atoms consisted of smaller particles that were interwoven with different charges.