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Take out hwk & tables.

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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

- Physicists have developed a theory called “The Standard Model” that explains what the world is and what holds it together.

Standard Model

- It was once thought that the fundamental particles were electrons, protons, neutrons.
- Now more & smaller subatomic particles found – quarks & leptons that comprise matter.
- Forces are carried by particles too!

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

- Charge = 0
- 1 up & 2 down.
- u d d
- +2/3 -1/3 -1/3 = 0

Leptons

- The most familiar member of this group is the electron e, but there are also heavier particles called the muon m and the tau t.
- For each of those, there is a smaller “partner” called a neutrino n .
- 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 type of particle is it?
- Write the symbols & charges for all the particles.

- c c b
- +2/3+2/3-1/3

What is its charge?

- +1.

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

- Write the symbols & charges for all the particles.

- What type of particle is it?

- s d
- +1/3-1/3

What is it’s charge?

- 0.

- Meson.

All independent particles must have whole number of elementary charge!

Forces & Force Exchange Particles elementary charge!4 Fundamental Forces

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

Force particles are gaugebosons.

- Strong Nuclear (Nuclear)
- Electromagnetic
- Weak (Nuclear)
- Gravity

Strong Force elementary charge!

- Short Range, Attractive only – holds nuclear particles together.
- Particle = gluons.

Electromagnetic Force elementary charge!

- Long range. Attracts & repels charged particles (Coulomb’s Law).
- Carrier particle = photon.

Weak Force elementary charge!

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

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

Gravity elementary charge!

- 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. elementary charge!http://www.youtube.com/watch?v=aTFCKbZw8QY

Hwk:

Read Text 25-4 pg 917-923

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

2. Bring back textbook!

Summary: elementary charge!

- EM energy can be thought of as tiny particles (photons) related to f.
- E in EM radiation/photons E = hf.
- Matter can be thought of as E stored in nucleus.
- E in matter E = mc2. Joules.
- 1 u = 931 MeV. 1 x 106eV = 1 MeV.
- E measured in eV and J.
- 1.6 x 10-19 J = 1 eV .

The charge on the quark below would be: elementary charge!

- +1
- -1
- +2/3
- -2/3

This particle is a: elementary charge!

- Lepton
- Proton
- Meson
- neutron

Cern Standard Model elementary charge!http://www.youtube.com/watch?v=V0KjXsGRvoA&feature=related5 minutes

Comprehensive Standard Model Summery elementary charge!(15 minutes)Cassiopeiahttp://www.youtube.com/watch?v=K6i-qE8AigE

Quantum Song elementary charge!

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

- What is Higgs Boson 3:30 elementary charge!
- 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. elementary charge!