Development of the Atomic Theory
By hugofetiza, Updated
Good morning, class! Today, we will be learning the development of the atomic theory. We will also tackle the discovery of certain particles that compose the atom.
In 430 BC, Democritus developed an atomic theory which states that all matter is composed of indivisible particles called "atomos"
Unlike my rival, Aristotle, who says all matter is made up of earth, water fire and air!
Yes yes, atoms are like building blocks of matter. They are small, indivisible and indestructible! Atoms look like a single ball of mass.
After roughly 2000 years, John Dalton proposed the "Ball Model" after some experiments.
Eugen Goldstein conducted an experiment with hydrogen gas and a CRT similar to Thomson. Some particles passed through the perforated circle which had a positive charge.
What are these particles that passed through?
I did this with my trusty Cathode Ray Tube. Remember: I call the negative particles "corpuscles"
In 1897, J.J. Thomson concluded that atoms were negatively charged particles stuck to a large positive particle. This model was called the Plum Pudding Model.
Soon after, in 1911, Ernest Rutherford conducted an experiment with a gold foil and gamma rays. After which, he proposed the "Nuclear Model".
Some rays passed through and some came back! I conclude that in an atom there is empty space and the electrons float like a cloud around the "Nucleus".
He also coined the term "proton"
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