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 + & n o 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 n o ? 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 Particles 4 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. =aTFCKbZw8QY =aTFCKbZw8QY Hwk: 1.Read Text 25-4 pg 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 = mc 2. Joules. 1 u = 1 p+, 1n o, = 931 MeV.
The charge on the quark below would be: +1 +2/3 -2/3
This particle is a: a. Lepton b. Proton c. Meson a. neutron
Cern Standard Model sGRvoA&feature=related 5 minutes sGRvoA&feature=related
Comprehensive Standard Model Summery (15 minutes) Cassiopeia qE8AigE qE8AigE
Quantum Song ayer_detailpage&v=DZGINaRUEkUhttp:// ayer_detailpage&v=DZGINaRUEkU
What is Higgs Boson 3:30 7uPywhttp:// 7uPyw What now for the Higgs 8:00 min w/ad. OKuEhttp:// OKuE
Regents Problems Wksht.