What is Matter?What is Matter?

Matter is anything that has mass. All objects are made of matter. Air, water, a brick, even you are made of matter!

States of matterStates of matter

VIDEO-Clip: http://www.britannica.com/EBchecked/topic/41549/atom

Atomic particles and isotopesAtomic particles and isotopes

Particles smaller than an atom.They may be elementary or composite.

Electrons (elementary)Protons (composite), made of 3 quarksNeutrons  (composite), made of 3 quarks

Subatomic particlesSubatomic particles

Over eighty years ago, scientists thought that the atom was the smallest piece of matter.

Atom: the building block of matter

John DALTON (1844)

Solid sphere model

John DALTONJohn DALTON

http://www.etownschools.org/Page/3502

John DALTON’s atomic theoryJohn DALTON’s atomic theory

VIDEO CLIP: http://www.britannica.com/EBchecked/topic/41549/atom

1940 John Thomson1906 Nobel Prize in Physics

John THOMSON discovered the electronsJohn THOMSON discovered the electrons 

The Cavendish Laboratory, Cambridge (UK)

Thomson at workThomson at work

A simple cathode ray tube. A simple cathode ray tube.

What could these rays be?  What could these rays be? 

VIDEO (3:46’) http://www.youtube.com/watch?v=4QAzu6fe8rE

He advanced the idea that cathode rays are really streams of very small pieces of atoms.

Do atoms have parts?Do atoms have parts?JJ Thomson suggested that they do!

J.J. Thomson experimenting

"We have in the cathode rays matter in a new state."

J.J. Thomson TalksJ.J. Thomson TalksAbout the Size of the ElectronAbout the Size of the Electron

To listen to J.J. Thomson speaking on his discovery:

Recording made in 1934. From the soundtrack of the film, Atomic Physicscopyright © J. Arthur Rank Organization, Ltd., 1948.

"Could anything at first sight seem more impractical than a body (the electron) which is so small that its mass is an insignificant fraction of the mass of an atom of hydrogen? --which itself is so small that a crowd of these atoms equal in number to the population of the whole world would be too small to have been detected by any means then known to science."

AUDIO: http://www.aip.org/history/electron/jjsound.htm

Raisin cake model

John THOMSON’s model of the atomJohn THOMSON’s model of the atom

J.J. Thomson theorized that electrons were surrounded by a positively charged material, uniformly distributed.

Ernest Rutherford discovered the nucleusErnest Rutherford discovered the nucleus

1937 Ernest RutherfordNobel Prize Solar system model1908

Rutherford’s experimentRutherford’s experimentThe gold-foil experimentThe gold-foil experiment

VIDEO: http://www.youtube.com/watch?v=Zd6_zVdMgJk

Alpha particle: helium nucleus (4u2+)

Expected results according to…..Expected results according to…..

Thomson’s modelThomson’s model Rutherford’s modelRutherford’s model

Rutherford envisioned the atom as a miniature solar system, with electrons orbiting around a massive nucleus.

Rutherford’s model of the atomRutherford’s model of the atom

Solar system model

What is Matter?What is Matter?

neutronsneutrons

mesonsmesons

Quarks and gluonsQuarks and gluons

Do you think that the quark is the smallest piece of matter or do you think that there

might besomething smaller inside the quark?

You name it!You name it!

You name it!You name it!

  The model of atom created by Rutherford shouldn’t exist!

According to classical physics, an electron in orbit around an atomic nucleus should emit electromagnetic radiation (photons) continuously.

The resulting loss of energy implies that the electron should spiral into the nucleus in a very short time (atoms cannot exist!!)

Quantized shell model

1962 Niels BOHR1922 Nobel Prize

Niels BOHR

In 1913 Bohr proposed his quantized shell model of the atom to explain how electrons can have stable orbits around the nucleus.

quantized shell model

Bohr proposed that electrons are restricted to certain fixed (quantized) orbits.

An electron can jump between these orbits by absorbing or emitting a photon with the appropriate precise wavelenght.

Fixed orbits

Bohr's idea was that each discrete orbit could only hold a certain number of electrons. After that orbit is full, the next level would have to be used. This gives the atom a shell structure, in which each shell corresponds to a Bohr orbit

Shell model of the atomShell model of the atom

VIDEO: http://www.britannica.com/EBchecked/topic/41549/atom/48360/Bohrs-shell-model

For working hard with me!For working hard with me!

VIDEO: http://www.britannica.com/EBchecked/topic/41549/atom/48360/Bohrs-shell-model

Electronic configuration of Electronic configuration of different atomsdifferent atoms

VIDEO: http://www.britannica.com/EBchecked/topic/41549/atom/48360/Bohrs-shell-model

Nuclear fissionNuclear fission

VIDEO: http://www.britannica.com/EBchecked/topic/41549/atom/48360/Bohrs-shell-model

Atomic bondsAtomic bonds

VIDEO: http://www.britannica.com/EBchecked/topic/41549/atom/48360/Bohrs-shell-model

Nuclear powerNuclear power