How do we know molecules exist
when we can't see them?

YouTube Channel


Brownian Motion

St. Mary's University
in Nova Scotia, Canada


The Real Thing

School Blocks YouTube?
Use the file below.



Fill In The Blank Notes


III. Early Models of Atoms


A) Rutherford Model of Atom (1911)



Copyright (C) 2000,2001,2002 
Free Software Foundation, Inc.

Listen to Rutherford talk
 about the atom 



Rutherford shot alpha particles at a thin gold foil to learn about the atom

Prentice Hall




Alpha particle

Thin gold foil



What explains their
curved path??





Repulsive electrical force
(A.K.A. Coulomb Force)




 Large deflection angles



Alpha Particle Scattering - Flash

[ HTML5 ]





Indicates strong forces



    Model Based on
Alpha Particle Scattering Experiment

Rutherford Experiment


Rutherford Scattering

 - © 1995-2007 by Michael W. Davidson
 and Florida State University

 Rutherford Scattering
Michael Fowler





1) Most of the volume of the atom is ...





Empty Space

(nucleus 1 x 10-15 m)




Did you know ...


A neutron star is created when a massive star runs out of fuel and collapses. This tremendous gravitational collapse squeezes all the empty space out of the atom. Electrons merge with protons and create neutrons.


The density of a neutron is so enormous that a teaspoon of a neutron star would weigh 20 billion pounds!!!


- Cornell Astronomy





Did you know ... If the
were the size of a football stadium, the
nucleus would be the
size of a






 .... a marble!!! 

That's why most alpha particles go straight through!!!


2) Virtually all mass atom found in ...





... the nucleus





3) Strong, positive charge in the center of atom



  That's why positive alpha particles were curved so strongly




"Other Side of Infinity"
Movie Trailer




Relative Sizes in the Atom 

Hear Thomson talk the Electron

Bohr Model of Atom




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Established 1995
Use any material on this site (w/ attribution)