Take out hwk & tables.

Compare answers to hwk sets.

List 2 pieces of evidence that light is a wave.

• Diffraction• Interference.

List 1 piece of evidence that light is a stream of particles.

• Photoelectric effect

List 1 piece of evidence for the Bohr model of the atom.

• Emission or Absorption spectra

Ref Table Page 3.

Standard Model

• Physicists have developed a theory called “The Standard Model” . It explains what matter and energy are, what holds matter together, and how forces are communicated.

Standard Model• It was once thought that the fundamental particles were

electrons, protons, neutrons.

• Now more & smaller subatomic particles

found – quarks & in the nucleus.

• Forces are carried by particles too!

Antimatter particles

• Same mass but opposite charge & spin.

• When a particle meets its antiparticle twin, they completely annihilate, destroy.

All matter classified Hadrons or Leptons Hadrons made from quarks.

p+ & no

Quarks can’t exist alone.

Protons, Neutrons: are baryons made of only up & down quarks.

• Ex 1. How many up & down quarks in a p+?

• Charge = +1

• Baryons have 3 quarks only.

• 2 up & 1 down.

• u + u + d

• +2/3 +2/3 – 1/3 = +1

• Ex 2: How many up & down quarks in a no?

• Charge = 0

• 1 up & 2 down.

• u d d

• +2/3 -1/3 -1/3 = 0

The Atom

Leptons

• The most familiar member of this group is the electron e, but there are also heavier particles called the muon and the tau .

• For each of those, there is a smaller “partner” called a neutrino .

• The leptons are all capable of independent existence.

All particles have anti-particles same mass.• Antiparticles behave same as corresponding matter particles, except

they have opposite charges.

• A proton is electrically positive - an antiproton is negative.

• Gravity affects matter and antimatter the same way.

• If matter & corresponding antimatter meet,

they annihilate into pure energy!

Antimatter Notation add bar to antimatter: Mesons quark & antiquark.

3. A particle is composed of 2 charm, & 1 bottom quark.

What is its charge? • +1.

• What type of particle is it?• Write the symbols & charges for all the particles.

• c c b• +2/3 +2/3 -1/3

4. A particle is composed of 1 anti-strange, & 1 down quark.

• What type of particle is it? • Meson.

What is it’s charge? • 0.

• Write the symbols & charges for all the particles.

• s d

• +1/3 -1/3

All stable particles must have whole number of elementary charge!

• Quarks cannot exist by themselves.

• No stable particle can have + 1 1/3 charge but can have

• +2, -1 etc.

Forces & Force Exchange Particles4 Fundamental Forces

• Strong Nuclear (Nuclear)• Electromagnetic• Weak (Nuclear)• Gravity

The universe exists because the fundamental particles interact. These interactions include 4 attractive & repulsive forces, decay, & annihilation.Force particles are gauge bosons.

Strong Force

• Short Range, Attractive only – holds nuclear particles together.

• Particle = gluons.

Electromagnetic Force

• Long range. Attracts & repels charged particles (Coulomb’s Law).

• Carrier particle = photon.

Weak Force

• In the nucleus. Involved with decay of particles. Short range.

The carrier particles of the weak interactions are the W and Z bosons.

Gravity

• Long range weakest force. Attractive only.

• The gravity force carrier particle has not been found. It, however, is predicted to exist and may someday be found: the graviton.

Quarks & Leptons 5:40 min.http://www.youtube.com/watch?

v=aTFCKbZw8QYHwk:

1.Read Text 25-4 pg 917-923

Do pg 923 #1,2 Pg 928 #30 – 37 Full sentences!

2. Bring back textbook!

Summary:• EM energy can be thought of as tiny particles

(photons) related to f.

• E in EM radiation/photons E = hf.

• Matter has E stored in nucleus.

• E in matter E = mc2. Joules.

• 1 u = 1 p+, 1no, = 931 MeV.

The charge on the quark below would be:

• +1

• -1

• +2/3

• -2/3

This particle is a:

a. Lepton

b. Proton

c. Meson

a. neutron

Cern Standard Modelhttp://www.youtube.com/watch?

v=V0KjXsGRvoA&feature=related5 minutes

Comprehensive Standard Model Summery(15 minutes)Cassiopeia

http://www.youtube.com/watch?v=K6i-qE8AigE

Quantum Song

• http://www.youtube.com/watch?feature=player_detailpage&v=DZGINaRUEkU

• What is Higgs Boson 3:30

• http://www.youtube.com/watch?v=RIg1Vh7uPyw

• What now for the Higgs 8:00 min w/ad.

• http://www.youtube.com/watch?v=649iUqrOKuE

Regents Problems Wksht.