Confirming the Existence of Atoms

Discovering Atoms

Atomic History: Democritus

  • The Greek philosopher Democritus (the same guy who invented democracy) hypothesized that matter was made of small spheres.

 

  • He believed these spheres to be indestructible and infinite in number.

Atomic History: Dalton

In the 1800s James Dalton Notices that elements always react in whole number ratios.

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Brownian Motion

Brownian Motion

Atomic Structure

Do atoms have constituents (parts), or are they in fact indestructible?

Atomic Nuclei

Soft and Fluffy

Hard

Peeking Inside Atoms

J.J. Thomson Discovers the Electron

Milikan Finds the Mass of the Electron

Deeper Structure

Do the parts of atoms have parts?

Yes!

Well, actually... maybe

How Did We Figure This Out?

Smashing Atoms

The analogy is often given that doing physics with “colliders” (a more technical term for “subatomic-particle-smashers”) is like smashing fine watches together and trying to figure out how they work from the pieces that come flying out!  There is merit to this analogy, but there’s something very important that is left out.

The act of colliding subatomic particles at very high energy is not merely a destructive act; it is, more profoundly, a creative one.

E = mc^2

Science's Most Famous Equation

Energy equals mass times the speed of light squared.

An Interesting Question

If all of scientific knowledge was to be destroyed, and you could leave only one piece of information for future generations, what would you tell them?

Atoms are Everything

Discovering Atoms

By Robert Sutherland

Discovering Atoms

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