Modern Physics

IntroductionTo examine the fundamental nuclear model

To examine nuclear classification

To examine nuclear fission and fusion

Detection Devices

Geiger counter

Scintillation counter

Cloud chamber

Bubble chamber

Superheated liquid

Fundamental Particles

Democritus introduced the word which in English translates as atom Elementary Particles The name given to protons, neutrons and

electrons

Today we use the term "fundamental" for the six types of quarks and the six leptons

Classification of MatterHadrons: Particles made of quarks. Protons, Neutrons and their Anti-particles

Leptons: Are NOT made of sub particles. Electrons are examples of Leptons

Hadrons are further broken into Baryons and Mesons. ( both break down into Quarks)

HadronsHadrons break down into two groupsBaryons are made of 3 Quarks Mesons made up of 2 quarks and

anti-quarks***(must add up to an integer not a

fraction)

Leptons

Leptons are fundamental particles that have no strong interactions

Lepton is Greek for "light particle”

electron there are heavier leptons, of which the first to be found was the muon

The TAU is 12th (quarks + leptons) fundamental building blocks of all matter.

Quarks

Quarks are fundamental matter particles that are constituents of neutrons and protons and other hadrons

Proton -- composed of two Quarks up quarks and a down quark

Sample Problem

A Baryon may have a charge of -1/3e0e+2/3e+4/3e

Correct answer is 0e (all types of matter must have an integer charge)

Scale of nature

Particles are classified by size and charge

Forces give all matter their characteristics and properties

Neutrinos (type of Lepton)

These particles are so small that they pass right through the Earth with interacting with a single atom!!!

Four fundamental interactions

Force : the effect on particle due to another particle

Interaction: the forces and decays which affect a given particle

Strong Force

Quarks and Gluons have a type of charge that is NOT electromagnetic

The “color” charged particles are very powerful (STRONG)

Quarks are glued together with GLUONS (Nuclear Energy)

Weak Force

The stable matter of the universe is made up of the two least massive quarks: UP and Down and the least massive Lepton, the electron ( A Hydrogen Atom)

When a quark or lepton changes type (muons changing to an electron) is called a “flavor” weak interaction

The components of the nucleus are called nucleons.

The two principle nucleons are the proton with a charge of +1e and the neutron which is uncharged.

All atomic nuclei (nuclides) and their components may be represented by the symbol below.

X is the name of the particle

A is the mass #

Z is the atomic #

XAZ XAZ

XAZ

Chemistry Symbols

Isotopes

Nuclei that have the same atomic number, but different mass numbers.

Hydrogen Deuterium Tritium

Nuclear Reaction

Represented by a balanced nuclear equation

HeCHN 42

126

11

157

Nuclear Fission & Fusion

Fission is the chain reaction splitting of an atom

Fusion is the joining of light nuclei to form a heavier more stable nuclei

Reference Chart : Standard Model

Reference Chart

Reference Chart Equations

Ephoton = hf = hc/wavelength

Ephoton = Ei – Ef

E = mc2

All equations calculate the amount of energy in units of eV or J. The conversion is based on the energy of a single electron or mass

Sample Problem

Calculate the energy of the photon that is emitted when a hydrogen atom changes from energy level n=3 to 2

Ephoton = Ei – Ef

= (-3.40 eV) – (-1.51 eV)

= - 1.89 eV

Sample Problem

What is the Radiant energy of a beam of light whose frequency is 5.0 x 1014 Hz

Ephoton = hf = hc/wavelength

= 6.6 x 10-34 J*s (5.0 x 1014 Hz)

= 33 x 10 -20 J

SummaryAtomic Particles are composed of sub-nuclear particles

The nucleus is a conglomeration of Quarks which manifest as Protons and neutrons

Each elementary particle has a corresponding anti-particle

The fundamental source of energy is the conversion of mass into energy