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The Penetrating Power of
Radiation
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LNK2LRN™ 2009/10 Physics Honors: Ch.30 - Nuclear Physics and Radioactivity. May 14 to 26. |
Daily Plans and Assignments:
1. Friday(05/14): Intro. to Ch.30, Nuclear Physics and Radioactivity.
HW: Read and Study pages 798-805, then answer questions 45, 48, 50,
and 53 on page 828.
2. Monday(05/17): Review of Nuclear Physics and Radioactivity.
HW: Complete Review Handout #1.
3. Tuesday(05/18): Nuclear Equations and Binding Energy. HW: Read
and Study pages 806-14, then answer questions 59, 61, 64, and 66 on
page 829.
4. Wednesday(05/19): Calculating Half-Life. Particle Accelerators and
Detectors. HW: Answer questions 73, 74, and 78 on page 829.
5. Thursday(05/20): LAB on Half-Life Simulation. HW: Process lab
data and plot graph (lab report due Tuesday).
6. Friday(05/21): Post-Lab Discussion and Problem Solving.
HW: Write lab report (due tomorrow).
7. Monday(05/24): The Building Blocks of Matter. HW: Read and
Study pages 815-823, solve probs. 79, 80, 81, and 82 on page 829,
and prob. 86 on page 830.
8. Tuesday(05/25): REVIEW Chapter 30 - Nuclear Physics.
HW: Complete all review handouts started in class.
9. Wednesday(05/26): TEST on Ch.30 - Nuclear Physics. HW: Visit
the web-site for notes and plans for Final Exam Review.
Very Important: If you have any questions, or were absent and
need to complete missing work, see me before school (8:00 -
8:30 AM), during Lunch, or after school. Best to send an email to
rpersin@fau.edu. Remember, all Make-up Work must be completed
within 3 days of absence.
Website Notes for Chapter 30: Nuclear Physics.
1. Henri Becquerel (1852-1908) accidentally found that all compounds
containing uranium emitted rays that penetrate and fog photographic plates,
after examining a mysterious rock.
2. Ernest Rutherford (1871-1937) identified alpha, beta, and gamma radiation
and used alpha particles to bombard gold foil. He found that most of an atom
is empty space but contains a massive positively charged nucleus.
3. The Curies, Pierre and Marie, were the first to discover other radioactive
elements, for example, Polonium and Radium.
4. The nucleus can be characterized by a mass number, A, an atomic number,
Z, and a neutron number, N, with A = Z + N. Atoms having the same number
of protons but different amounts of neutrons are called isotopes.
5. The nucleus of an atom contains most of the mass, consists of protons
and neutrons, with protons and neutrons termed as "nucleons."
6. We use the Atomic Mass Unit (amu), or u, for nucleon mass. To convert just
use the fact that 1 u = 1.6605x10-27 kg. This means that we now have the
mass of a proton as, 1 p = 1.007825 u, and a neutron, 1 n = 1.008665 u.
7. The change, transmutation, in an atomic nucleus can be natural or artificial.
Enrico Fermi (1901-1954) successfully produced artificially radioactive elements
in the laboratory.
8. Radioactive decay produces three kinds of particles: alpha,
α, helium nuclei;beta, β, high-speed electrons; and gamma,
γ, ray photons.9. Bombardment of nuclei by protons, neutrons, alpha particles, electrons,
gamma rays, or other nuclei can produce a nuclear reaction.
10. Linear accelerators, synchrotrons, and super-colliders produce high-energy
protons and electrons which can collide with each other or an atomic nucleus.
11. Particle detectors include photographic plates, the Geiger-Muller tube,
scintillation screens, and the cloud chamber.
12. Alpha can be stopped by thick paper, beta by thick aluminum foil, and a
few centimeters of lead will stop gamma.
13. During positron decay a proton changes into a neutron with the emission
of a positron and a neutrino.
14. When matter and antimatter combine, all matter is converted into energy,
or lighter matter-antimatter particle pairs. By pair production, energy is
converted into a matter-antimatter particle pair.
15. The weak interaction operates in beta decay while the strong force binds
the nucleus together. During beta decay a neutron changes into a proton and
the nucleus emits a beta particle and a mass-less antineutrino.
16. The binding energy is the energy equivalent of the mass defect. The
assembled nucleus has less mass than its constituent parts due to mass-to-
energy conversion, Binding Energy = (Δm)c2 , with Δm as the mass defect.
17. Nuclear reactors use the energy released in fission as heat to boil water,
which produces steam, that turns turbine blades to run a generator.
18. The binding energy of the nucleus is the difference in energy between its
nucleons when bound and its nucleons when unbound. Energy-mass equivalence
can be computed using 1 amu = 931 MeV.
19. The half-life, T½ , is the time required for half the original nuclei of a
radioactive substance to undergo radioactive decay. We use the equation
A = A0∙2-n where n is the number of half-lives, and A indicating amount.
20. The decay constant, lambda, λ, indicates the rate of radioactive decay.
Half-life can also be calculated by T
½ = .693/λ .21. Nuclear reactions involve a change in the nucleus and can be given by
equations. In equations for nuclear reactions, subscripts and superscripts must
agree on both sides.
22. In a nuclear equation the sums of the subscripts (atomic number or particle
charge) on both sides of the equation are equal and the sums of the superscripts
(mass number) on both sides of the equation are equal.
23. In fission, heavier nuclei split to form lighter nuclei and energy is released.
In fusion, lighter nuclei combine to form heavier nuclei with more binding energy.
24. Physicists currently believe there are three types of basic building blocks of
matter: quarks, leptons, and bosons.
25. Quarks and leptons make up everyday matter, which is held together by
bosons. Each boson is associated with a force.
26. The photon, the unit of the electromagnetic force, holds the electron to
the nucleus in the atom. The way these particles combine dictates the structure
of matter.
27. And to get full credit for your homework make sure you are following
these steps
(i) read the problem and identify the given variables
(ii) determine what you are asked to solve for
(iii) find the correct formula to use
(iv) use algebra to isolate the unknown
(v) substitute-in the given information and simplify.
THE
HONORS PHYSICS ARCHIVES| Building Blocks of Matter |
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And Always Remember... "From Newtonian Mechanics, Through Quantum Theory, Without Physics, Life Would Be Dreary." |
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