A glance into History

Journals of the Scientists as they developed the atomic theory of their day

Student Name

Period

Journal of Democritus, March 12, 345BC

Today I was in a discussion with my fellow philosopher, ______who believes that all matter is made of the four elements, ______, ______, ______& ______. It is so frustrating to hear his thoughts when I feel so much that matter is indivisible, so I call it ______.

If I were to draw the atom

it would look like this:

These are the five things I truly believe about matter...

I sure hope that many people believe my stand on atomos, but only time will tell.


Journal of John Dalton September 2, 1795

I have been studying the work of the alchemists and I believe we need to change our ways so that we have more of a

______science where we measure and record what happens in a reaction, rather than the observational qualitative science that has been seen for so many years. I am glad that

______said that no matter can be created or

destroyed, creating a new law of ______. I hope that a new revolution of chemistry will begin now.

~June 18, 1803

I will soon announce to the world my theory of the atom. I have been doing many quantitative experiments, and have found the

______of elements as they react. This has lead me to

believe it was ______, not Aristotle who was correct so many years ago.

I suppose I should write my theory here as I will publish it soon.

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Journal of JJ. Thompson August 5, 1885

I have been working with this new equipment, the CRT or ______and I am excited about what we are learning. When we pump the ______out of the tube we can pass ______through the tube and observe it. We thought at first that it was just a ray, but eventually we found that the rays were actually ______.

I think I will work to find out how much ______each of these particles has compared to its ______. What interesting things we are learning!

~January 10, 1890

What a day! We have finally deduced more information about these particles. It turns out that our big finding is

I think that instead of the old way of looking at the atom we will now need a new model, and I believe it will be similar to my favorite dessert, ______

I believe that the atom actually looks like this:

Journal of Ernest Rutherford May 17, 1905

I have been looking at JJ. Thompson's model of the atom and I think I can use the atom to study ______particles. If his model is correct the particles should do the following when they pass through the atom:

I am going to create an experiment to test this hypothesis. I will pass the alpha particles through ______to confirm my hypothesis.

~December 3, 1911

Wow, today was amazing! We tested my hypothesis and found that it was ______. Here is what happened in my experiment:

Based on these findings I can no longer support the thought that the atom looks like JJ Thompson's plum pudding model, instead I would draw the atom as follows:

I think I will call the positive particle in the atom the ______... yes, that does have a nice ring to it.


Journal of Niels Bohr August 6, 1915

I have been looking over Rutherford's data from his ______experiment and I have also seen that my fellow scientist Plank talks about energy levels. The evidence supports the fact that a new model of the atom is needed because Rutherford's model does not take into account the specific energy levels we have seen.

Each ______has an energy level. When electrons are in the lowest ______they are said to be in the ______, but when ______they can move up to higher levels.

There are two ways to draw my new model.

To show what the atom would look like in a more three dimensional form I would draw it like this:

To explain the electron energy levels, I would "flatten out" each of the electron orbital lines and you can see the distance between electrons more easily, as I have drawn here:


Journal of Erwin Schrodinger October 14, 1920

I have been looking at Bohr's new model of the atom, but it just doesn't explain everything. I mean, it's a helpful way to imagine the

but I want to include more information about

I will need to study this and begin experimentation to find a new model.

~January 10, 1926

I have been experimenting and working out all of the math, and I believe I finally have a way to describe the atom! The thing is we cannot know where

That means I must base my model on

I believe I will use quantum numbers as coordinates to

This means that the probable area of finding an electron is represented by

The atom is made of all of these probability orbitals layered on top of one another as you can see in my drawing:

Journal of James Chadwick

April 13, 1930

Ah, so many things to bombard. This ______particle is great! We can study so much with it. Already the head of my lab, ______discovered the nucleus using these particles in the ______experiment, but I think there could be more to this.

There is evidence of radiation emitted when alpha particles hit Berillyum, and others say it is gamma rays because it has no charge. I am going to create an experiment to find out what that radiation is really made of.

November 28, 1932

Wow! Who would have known... it turns out that the uncharged radiation was really a ______and I have decided to call it a neutron. My experiment went like this:

Now that we know there is another particle, we will need to re-draw the nucleus to include it, and it will look like this: