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

PhysicsAnimations
YouTube Channel

 

Brownian Motion

St. Mary's University
in Nova Scotia, Canada

 

The Real Thing

School Blocks YouTube?
Use the file below.

Brownian_motion.mov

 

 

showmethephysics.com

Slideshow

 

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
Onsite

 

 

 

Alpha particle

 Thin gold foil

 

 

What explains their
curved path??

 

 

 

 

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

 

 

Unexpected:

 Large deflection angles

 

 

Alpha Particle Scattering - Flash

[ HTML5 ]

showmrthephysics.com

 

 

 

 

Indicates strong forces

 

 

    Model Based on
Alpha Particle Scattering Experiment

Rutherford Experiment

 www.CosmoLearning.com

(onsite)

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

 Rutherford Scattering
Michael Fowler

 

showmethephysics.com

Slideshow

 

Conclusions:

 

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

Space_Between_Atoms

Space_Between_Atoms

 

 

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

Cornell

 

 

 

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

 

 

 

 

 

 .... a marble!!! 

- Encyclop. of
Science

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

showmethephyics.com 

Hear Thomson talk the Electron





Bohr Model of Atom

 

 

 

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