1. alpha particles scattering experiment
1.1. nearly all of the alpha particles passeed throught the gold foil while a small number were deflectd and a few even bounce back
1.2. all the positive charge and mass are conentrated in the nucleus whihc is at the center of the atom, the nucleus is very small (10000th of size of an atom). The rest of the atom was largely empty space
2. weak interaction
2.1. one of the four fundamental interactions of nature
2.2. the weak interaction between quarks gives rise to beta decay
2.3. the weak interaction is caused by the emission or absorption of W and Z bosons
3. nuclear decay
3.1. unstable nuclei become other nuclides by emitting alpha, beta or gamma ray spontaneously and randomly
3.1.1. spontaneous
3.1.1.1. decay cannot be controlled, it's independent on external conditions such as T and P
3.1.1.2. random
3.1.1.2.1. uncertain which nucleus is the next one undergo decay
3.1.1.2.2. count rate fluctuate
3.2. mass- energy are all conserved
3.3. alpha, helium nuclueus
3.3.1. least penetrating power, most ionizing power
3.4. an elementary/ fundamental partcile is a particle whose substructure is unknown
3.5. beta
3.5.1. stream of high energy e- emmited
3.5.2. medium
3.5.3. a range of velocity because of the antineutrino
3.6. gamma
4. particles
4.1. elementary particles
4.1.1. protons and neutrons are not the elementary particle because they consist of quarks
4.2. families of particles
4.2.1. elemenatary particles can be classified into fermions and bosons
4.2.1.1. fermions compose the ordinary matter
4.2.1.2. bosons are called 'force carrier particles'
4.3. fermions
4.3.1. total 24
4.3.1.1. 6* quarks and antiparticles
4.3.1.2. 6 * leptons and antiparticles
4.3.2. electromagnetic radiaiton
4.3.2.1. most penetrating
4.3.2.1.1. least ionizing
4.3.3. strange
4.3.4. quarks:
4.3.4.1. up
4.3.4.2. down
4.3.4.3. charm
4.3.4.4. top
4.3.4.5. bottom
4.3.5. leptons:
4.3.5.1. electron
4.3.5.2. electron neutrino
4.3.5.3. muon
4.3.5.4. muon neutrino
4.3.5.5. tau
4.3.5.6. tauneutrino
4.4. photons are the force carrier of electromagnetic force, W and Z bosos are force carriers of weak interaction
4.5. particles and antiparticle
4.5.1. every particle has a distinct anti-particle with the same mass but opposite electric charge. Some particles like photon are their own anti particle. Neutrinos do not carry any electric charge.
4.6. bosons
4.6.1. photon
4.6.2. gluons
4.6.3. W+-
4.6.4. Z bosons
4.7. hadrons are composite particles made up of quarks which held together by strong interaction e.g. neutron, pion
4.7.1. baryons
4.7.2. mesons
4.7.2.1. composite particles amde up of one quark and one antiquark(no meson is stable)
4.8. quarks
4.8.1. +2/3 e
4.8.1.1. up
4.8.1.1.1. top
4.8.2. -1/3 e
4.8.2.1. down
4.8.2.1.1. bottom
4.8.3. proton, 2 up 1 down
4.8.4. neutron
4.8.4.1. udd
4.8.5. pion
4.8.5.1. u d(dash)
4.9. leptons
4.9.1. are elementary particles that does not undergo strong interactions. electrons have the least mass of all the charged eptons . The heavier muons and taus will rapidly change into electrons through a process of particle decay
4.10. composite particles made up of 3 quarks, e.g. proton, antineutron
4.11. neutrino
4.11.1. elementary leptons which interacts via weak interaction and gravity
4.11.2. three flavors
4.11.2.1. electron/ muon/ tau
4.11.3. different to be detected because they are eletrically neutral, the mass is tiny compare ith toher subatomic particles