bell ringer what are the three subatomic particles? (things smaller than an atom, you learned in 8...
TRANSCRIPT
BELL RINGER
What are the three subatomic particles? (Things smaller than
an atom, you learned in 8th grade)
History of the Atom
Where it all began…The atom starts not with the ________ of
the atom, but the ______ of the atom.
More than ______ years ago, (around ____ BC) Greek philosophers, ___________ and ____________ debated the nature of the universe.
historyidea
2000
Aristotle Democritus400
AristotleDemocritus
Get this…Aristotle believed that all matter was made of ___ elements: ______, ____, ______ and _______.
4 Earth Air FireWater
Democritus believed that matter was made of small particles called ______ that cannot be _____________.
atomsbroken down
Who WON the debate and who was RIGHT?
Democritus based his theory on ___________, Aristotle based his on __________. Neither of them really did _____________.
observationphilosophy
_______ argued louder, so he won.
Aristotle’s ideas then carried through until the _____________.
Democritus was actually _______.
Aristotle
experiments
Middle Ages
RIGHT
A branch of science called _________ was introduced to Europe in ______ AD.
Alchemists tried to change ______ to ______.
alchemy
leadgold
What happened next?
1144
“SHOW ME THE MONEY!”
Alchemy Symbols
Alchemists were ___________ in changing lead to gold – a process called _____________
*(_________ one substance into _______.)*
unsuccessful
transmutation
Changing
another
The Father of Atomic TheoryModern atomic theory was developed in 1809 by an English scientist named _____ ________.
His theories were based on ___________ and ___________.
John Dalton
observations experiments Dalton’s Atomic Theory
1. Matter is made of small particles or atoms.
2. Atoms cannot be created or destroyed.
3. All atoms of an element are identical and have the same mass.
4. Atoms of different elements have different masses.
5. Compounds are formed by combining different elements.
Who’s Next?
In _____, an English physicist named ______________ did experiments to determine the parts that make up the atom.
1897J.J. Thomson
He created a ________ ray tube: a _______ tube where all the ____ has been pumped out and a limited amount of other ______ is pumped in.
cathode vacuum air
gases
Thomson’s Experiment
Voltage source
+-
Metal Disks
Passing an electric current makes a beam appear to move from the negative to the positive end
Thomson’s Experiment
Voltage source
+-
Voltage source
Thomson’s Experiment
By adding an electric field to the outside of the tube, he discovered that the moving pieces were negative.
+
-
EUREKA!
The negatively charged particles were called corpuscles by Thomson but the name was later changed to ________.electrons
Thomson developed a model based on his findings and it was called the ____________ model.plum pudding
Positive “pudding”
Negative “plums”
Next up…
In _____, an English physicist named _________________ continued Thomson’s work.
1910Ernest Rutherford
He believed the plum pudding model was correct, but wanted to discover the _____ of atoms.
size
Rutherford’s experiment
The radioactive material released ______ particles, which would _____ when in contact with the fluorescent screen.
alphaglow
To do this… Rutherford used thin ________ sheets and ___________ material.gold foil radioactive
Lead block
Uranium
Gold Foil
Fluorescent Screen
This is what it looked like:
He thought…
The alpha particles would pass through the foil without ________ _________.changing direction
positiveevenly
Because…
The _______ charges would be spread out _______, and were not close enough together to repel the positively-charged alpha particles.
Hypothesis…
Why this?
Positive “pudding”Positive alpha
particles
What really happened…
Explanation please:
+
Atoms are mostly ______ ______.empty space
There is a ______, _______, ________ charged area at the center of the atom – called the ________.
smalldense positively
nucleus
The positive alpha particles were _________ by the nucleus if they got close enough…and thus we have the _______.
deflected
Nucleus
proton
Like Charges REPEL!
+
The Bohr ModelThe next model of the atom comes from a Danish chemist, _____ _____, who developed it in _____.
Niels Bohr
In this model the ________ are located in the nucleus and theprotons
_________ are located in pathways around the nucleus.
electrons
1913
Modern Model of the Atom
The wave mechanical or electron cloud model was introduced in ______ by Schrodinger and Heisenberg.
In this model the electrons do NOT follow a set path, they have wiggle room.
Because of this you cannot predict the location of an electron at a given time.
1926
Last but not least…
James _________ discovered the last subatomic particle in _____.
The _______ was so difficult to find because it does not have a ______, it is _______.
Chadwick’s discovery earned him the nickname: ______________ (sound familiar?)
Chadwick1932
neutroncharge neutral
Jimmy Neutron
BELL RINGER
Name a scientist who helped with the history of an atom and
tell what he explained about the atom.
Make a TIMELINE!
• Using your notes, make a timeline of Atomic Events in History!
• Use the paper provided and the colored pencils!
• Make it creative, but ACCURATE!• Include pictures, too!