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.
1.
2.
3.
4.
5.
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: