Conceptual Physics II, Day 10

Did questions chapter 32.

Handout on radiation effects. About an hour on radiation effects

Assigned three questions on nucleus:

  1. Scale model of nucleus
  2. Decay and halflife, how can you affect halflife
  3. Stability of deuteron

Followup on Rutherford, fission and fusion intro.

Compare the size of the nucleus to the size of the atom.

How are the sizes of such small things measured?

What is radioactivity and why does it happen?

Describe the three most common types of radioactivity.

Which of the types of radioactivity is most dangerous outside your body? ... inside your body?

How do the energies involved in radioactivity compare with those in atomic spectra, visible light, etc.?

What is meant by radioactive half-life? Given an amount of a radioactive substance, how much will remain after three half-lives?

What effect will raising the temperature of a radioactive substance have on its half-life? What effect will combining it into a chemical compound have? If a radioactive sample is vaporized, will that decrease its half-life?

How can you tell if an amount of radiation is a health hazard?

What kind of objects may be dated by carbon dating? About what maximum age would you expect to be able to determine with carbon dating?

What do you mean by "clocks in the rocks"? What sources of uncertainties are inherent within radioactive dating techniques?

*Nuclear forces

*Nuclear scale model

*Rutherford scattering





*Energies of radioactivity


*Half-life concepts

*Radiation risk

*Carbon dating

*Clocks-in -the-rocks

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Conceptual Physics II, Day 11

Nuclear questions from text.

Radiation lab

Nuclear energy discussion

How can energy be obtained by nuclear fission? What isotopes are useful for such energy processes?

How can energy be obtained by nuclear fusion? What fuels seem to be most practical there?

Outline the difficulties which have been encountered with nuclear fission energy production.

If fission has problems, why don't we use fusion instead?

Given that fusion requires incredibly high temperatures, how do we contain such hot stuff?

What is a fast breeder reactor?

What is the role of the water which jackets the fuel in U.S. nuclear reactors? What do you mean by "moderation" in this context and why is it necessary?

If you were told that you had been accidentally exposed to a radiation dose of 10 millirems, what would that mean to you? Are you doomed? Can you just ignore it?

What kinds of radioactive isotopes are most dangerous if released into the environment and why?

Why does nuclear fission produce so many radioactive byproducts compared to nuclear fusion?

What is meant by "critical mass"? If a nuclear fission reactor has more than a critical mass of uranium-235, does that mean it can explode like a bomb?

*Energy from mass

*Fission energy

*Fusion energy

*Three-mile Island


*Magnetic bottle

*Inertial confinement

*Fast breeder reactor

*Water moderator

*Meet the millirem

*Radiation risk



*Fission fragments

*Critical mass

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Conceptual Physics I, Day 12

Spent first hour with a continuation of Chernobyl discussion.

Did relativity concepts, but it was just too much for them. In third hour I set 7 relativity questions to groups. They seemed to relate better. Just got through 4 presentations.

What evidence do we have that the velocity of light is a universal constant? What is the significance of that observation?

Why do we say that the speed of light is the speed limit of the universe?

If you could make a detailed observation of the Enterprise as it passed the Earth at 90% of the speed of light, what conclusions would you draw about the measurement of lengths and times on the ship?

If you were on the Enterprise moving at 90% of the speed of light past the Earth, what observations would you make about the measurement of length and time on the ship?

What kinds of evidence exists for length contraction and time dilation in real experiments?

If you were in a spaceship traveling past the Earth at 0.9 c and another spaceship was traveling toward you, also at 0.9 c, with what speed would you see the other ship approaching?

You encounter the terms "Galilean transformation" and "Lorentz transformation" often in literature about relativity. Under what conditions are the different transformations needed to describe nature?

What happens to the mass of an object as it approaches the speed of light? Does light have mass? Does light have momentum?

Describe the implications of Einstein's famous equation, E=mc^2 . How does it handle kinetic energy?

What is the principle of equivalence? Why is it important in the search for the effects of general relativity?

What is the difference between special relativity and general relativity?

What experiments are cited to support the ideas of general relativity?

What is meant by gravitational red shift? Has it been observed?

What ideas from relativity suggest the existence of black holes?

*Ideas of relativity

*Michelson- Morley experiment

*Aberration of starlight

*Double star images

*Relativity concepts

*Speed limit

*Relativistic mass

*Length contraction

*Time dilation

*Muon experiment

*Einstein velocity addition

*Galilean transformation

*Lorentz transformation

*Momentum of light

*Mass of photon?

*Cambridge example


*Relativistic kinetic energy

*Principle of equivalence

*General relativity

*Advance of perihelion of Mercury

*Bending of starlight

*Gravitational red shift

*Gravitational time dilation.

*Red shift examples

*Black holes

*Cygnus X-1

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