Activities to Supplement the Nuclear Science Wallchart

 

Gordon J. Aubrecht, II, Department of Physics, OSU, Columbus, OH 43210-1106 and Marion, OH 43302-5695

Margaret A. McMahan and

Eric B. Norman,

Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720

What is CPEP, the ?

 

CPEP is a non-profit organization of teachers, educators, and physicists located around the world. CPEP materials (charts, software, text, web resources) present the current understanding of the fundamental nature of matter and energy, incorporating the major research findings of recent years. During the last decade, CPEP has distributed over 100,000 copies of its charts and other products.

•High school teachers have been part of this project from the beginning.

•Workshop at the January, 1998 AAPT meeting in New Orleans generates ideas from high school and college teachers.

Suggested activities: Sizes

1. Comparison with the solar system model; what’s useful?; what’s misleading?

2. Density comparisons: squeeze a sponge to compare densities or compare a brick of Pb with a brick of water (15:1), and imagine the core of Sun compared to water (150:1). (Students don’t need a brick of water, they know what it feels like.)

3. Connect sizes with distance over which the weak force, other forces operate.

4. Fix the size of universe with the state of matter. Take two experimental points, e.g., when the universe was this old, it was this hot, it was the size of Jupiter’s orbit, matter looked like this, wavelength corresponding to this temperature, reaction rate (?). This much time later, it was this hot, it was the size of..., matter looked like...

5. Experiments in contemporary physics correspond to when the universe was ... (have students try to fill in the blanks).

6. Calculate the mass of a spoonful (a beakerful) of the Sun. Calculate the mass of a spoonful of neutron star material.

7. Blow up balloons with pennies taped to it to see the way the Universe expands.

 

Suggested activities: the Sun

 

1. Work backward: 1.4 kW/m2 solar constant at Earth orbit Æ Psun; how big is it?

2. How to obtain energy on Earth if we start from Sun? (converse problem to #1: knowing the Sun’s luminosity, what is the energy flux at Earth’s orbit?)

3. What is the amount of matter needed to produce 1 MJ of energy?; or, Is the sun made of coal, uranium, or hydrogen?; or, How old is the sun if it is made of coal, uranium, or hydrogen?

4. How do we sustain a fission reaction?

5. What is the difference between a bomb and a reactor?

6. Starting from the luminosity of the Sun, calculate how much mass is being converted into energy every second in the Sun.

7. Estimate the flux of neutrinos reaching Earth from the Sun.

 

Suggested activities: Radiation

 

1. How much energy per photon is there for radiation we "know": microwave, IR, visible, UV, and compare this to the case for x rays and gamma rays: 3 points equally spaced (and explain what equally spaced means in scientific notation).

2. Investigate the difference between IR and gamma radiation (that is, nonionizing and ionizing radiation). Why are these different? [This is based on the thinking in #1.]

3. The photoelectric effect: does it affect tissue?

4. Have students look at the effect of disruption of chemical bonds. We’d like to have students see that the effect occurs whenever binding energy of a particular system is exceeded: none, then chemical, then ionizing.

5. UV light on deli slices as a student project; compare spoilage time for corned beef if bought at 8 am or 3 pm, compare if deli uses UV light. Why would UV make a difference? Does it?

6. Irradiated food: What is it? Why does it work? [they’d need a definition of irradiation]

7. Hospital materials are sterilized by irradiation. How does this do anything? What does it do?

8. What issues are involved with safety in a space ship (cosmic rays do an astronaut more damage inside than outside). Do astronauts have to be concerned about radiation shielding?

9. What thickness stops a photon? Can a photon really be stopped? Can all photons in a beam of photons be stopped?

10. How do we measure solar neutrinos?

11. Consider radon levels in homes. Where does radon come from? Why are some areas more prone to radon problems than others? How does radon enter a home? How can we ameliorate the problem?

12. Have students consider a nuclear waste shielding experiment.

13. Do a half life calculation.

EXAMPLE:

The famous archaeologist Prof. I. Wannabee is profiled in Lifestyles of Interesting People magazine after announcing that an 4.000 g piece of a spice box (wood is C6H11O5) found in an Egyptian pyramid was radiocarbon dated in Wannabee’s lab to 10 000 BC in a special week-long counter experiment. Wannabee claims that this measurement proves that all current archaeological beliefs about the timing of Egyptian civilization are wrong. Should you write a letter to the magazine exposing Wannabee as a liar? Why or why not? Explain. (The half-life of 14C is 5730 years. Naturally occurring radioactive

C makes up 1.3 x 10-10% of carbon at any time.)

Suggested activities: Risk

1. What is the difference between perceived vs. actual risk?

2. Have students investigate how the effect of Chernobyl (distributed in the biosphere) compares to 70 years of background radiation. Do other Chernobyl-based questions.

EXAMPLE: Pripyat problems

Ukrainian observers during the Chernobyl disaster who were walking through the streets of Pripyat measured exposures of between 0.18 and 0.60 R/h. [A röntgen (R) corresponds to exposure to 0.0877 J/kg of ionizing radiation.] What average exposure and dose would the people of Pripyat have received in the 1.5 days between the accident and the evacuation? Assume the biological effectiveness is 10 times amplified over the measured values in air. If 150 leukemias per million people per gray per year result from exposure, to how many eventual leukemias would this correspond?

3. Pick a candle: driving, smoking, living with smoker. Start simple: how many days would you trade giving up a cookie for one banana split (I can’t imagine a group of high school students who can imagine why they don’t get both).

4. Compare the LD50 for alar, nuclear waste, car miles, tobacco, 100 kWh of nuclear waste (so they learn how much, or how little there is), 100 kWh coal waste.

 

EXAMPLE: Compare using microrisk (Idea from George Marx).

Activities entailing 1 microrisk

(risk of 10-6 cancers per person)

2000 km of traveling by plane

2500 km of traveling by train

80 km of traveling by bus

65 km of driving a car

12 km of bicycling

3 km of motorcycling

1.5 cigarettes

living with a smoker for 2 months

drinking one-half a liter of wine

living in a brick house for 10 days

breathing polluted air for 3 days

5. Objective vs. subjective risk: diet, where we worry about "calories," fat, sodium.

6. Have students do web searching for comparing risks of radon, concentrations of radon, compare to EPA standards.

7. Compare voluntary with involuntary risk: flying vs. driving, for example.

8. Consider the radiation from a smoke detector and biological waste. Is it risky to be near either one?

Suggested activities: Fission, fusion, and decay

 

 

1. Figure out in detail what nuclear reactions could be used in order to transmute other materials into gold. How much gold could be made this way? Is it a good way to get rich?

2. Alternatively to #1, investigate alchemy: how would we make Au from Pb (start with Au deteriorating, work backwards)

3. Follow in detail (i.e., keeping track of A, Z, N, etc.) decay chains of isotopes such as Th-232, U-238, Element 112 all the way to stable nuclei if possible.

4. Explore the history of and the reactions used to produce the "man-made" elements beyond uranium.

5. Try to simulate nuclear reactions (e.g. fission, fusion, elastic scattering) using gliders on air tracks.

6. Alpha, beta, gamma sources with Geiger counter, shielding–as much as possible, pick sources we’re familiar with: body, concrete, salt substitute.

7. Roll dice: they can be special dice (say, 8-sided), or maybe regular dice where 2, 3, or 7 indicates a decay. Or different results to give different paths: no decay, alpha, beta, gamma. Start with 50 atoms or so. Use yellow dice for initial decay and red dice for daughter decay.

 

What next:

actual:

•Engage our high school and college teachers to expand on the ideas they’ve created to produce materials for use in the classroom

•Workshop at AAPT meeting in Lincoln, Nebraska in August

•Get participants at this APS meeting to contribute (or even work on) ideas

possible/probable:

•Teacher test the materials developed

•Select best materials, make modular and market through our agent, Science Kit and Boreal Laboratories

•Add some materials to web site

•practice, practice, practice

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