Theory of the Atom

Philosophy:
Study what makes the universe work by using examples and the human mind
Science:
Study what makes the universe work by observation, experiment and physical proof

Once Upon A Time
* He also believed that the moon and stars were planets far away from us.
p. 80 in text

• Philosopher
• Tutor to Alexander the Great
Everything comes from the 4 elements p. 81 in text

Meanwhile…..
Alchemists- tried mixing different materials together to make new things medicine
Acids for dissolving things
Cleaning chemicals
Love potions
Magic spells

Meanwhile…..
Some alchemists believe in a
“Philosopher’s Stone”
Transmute – change one material into another
Because of the fakers, alchemy became illegal almost everywhere, so they had to “go underground”

Meanwhile…..
Alchemists- by doing experiments in which they broke complicated chemicals into simpler ones, discovered different “pure” substances.
Pure means these substances are not mixed with something else – ex wood is made of other things and will break down, but Gold cannot be broken into anything simpler.

Meanwhile…..
These pure substances become known as
“elements”. Alchemists realize that there are actually many elements not just four.

Meanwhile…..
Different materials are made by mixing together these elements in certain proportions:
Water is H
2
0 . It is ALWAYS 2
Hydrogen and 1 Oxygen hooked together.

1803 John Dalton
England – Quaker school teacher
Each element is a different kind of “building blocks” atoms p. 81 in text

1803 John Dalton
p. 81 in text

1803 John Dalton
p. 81 in text

1803 John Dalton
•Atoms are the smallest particles and cannot be broken into smaller units
•Atoms of the same element are the same. Different elements= different kinds of atoms
•Atoms join in certain proportions to make new substances.
p. 81 in text

1897 J J Thomson England
Experimented with the cathode ray tube

crt

tv

1897 J J Thomson England
•Experimented with the cathode ray tube
•Decided atoms actually have TWO parts mostly positive with little negative chunks

1897 J J Thomson England
• His model for explaining the atom became known as

1909 Ernie Rutherford from New Zealand
•Student of Thomson
•Experiments with new-fangled discovery “radiation”
•Decides to shoot radiation at
Thomson’s pudding

1909 Ernie Rutherford
Why
Gold?
Radioactive material
If the atom is like pudding, the beam should punch right through

1909 Ernie Rutherford
It turned out some of the particles bounced off something

1909 Ernie Rutherford
Ernie decided the atom was mostly empty space with the positive part in the center and the negative particles orbiting
This is the
Solar System
Model

1913 Niels Bohr -Denmark
•Agreed there are
+ and – particles
•Proves that – particles actually change paths according to the amount of energy they have
•Paths have different shapes, not circles

1913 Niels Bohr
Niels Bohr model
Energy Level model

Modern Theory
Erwin Schr Ö dinger
Werner Heisenberg
- particles are so tiny and moving so quickly, we can’t actually predict exactly where they are, only where they are most likely to be.

Modern Theory
Erwin Schr Ö dinger
Werner Heisenberg

Parts of an atom
Positive particles in the center
PROTONS
Negative particles orbit the center
ELECTRONS
WHAT HOLDS THEM
TOGETHER????

1932 James Chadwick
England
We can explain that the negative particles stay in orbit because opposites attract

1932 James Chadwick
England
What keeps the positive particles in the center from flying apart?

Parts of an atom
Chadwick used the weights of the atoms to prove there are actually neutral particles between the positive particles

Parts of an atom protons nucleus neutrons electrons
This is what you need to know to learn chemistry

This is what you need to know to learn nuclear physics
Quarks http://science.howstuffworks.com/atom-smasher11.htm

If you are REALLY interested, check out this link!
http://io9.com/5639192/the-ultimate-field-guide-to-subatomic-particles

Parts of an atom
Quarks protons neutrons up down charm strange top bottom electrons leptons http://science.howstuffworks.com/atom-smasher11.htm

How do I find information about an atom?
Use the Periodic Table
Atomic mass
Atomic number
Chemical symbol
Element Name

Atomic number
Number of protons in an atom
TOTAL number of particles in the
Abbreviation for the element name –may

Check these out!!!!
http://particleadventure.org
http://www.nuclecu.unam.mx/~alberto/physi cs/string.html
http://www.fnal.gov/pub/inquiring/matter/ma deof/index.html
http://www.chem4kids.com