TITLE OF LESSON PLAN:
Savage Sun

LENGTH OF LESSON:
Two class periods

GRADE LEVEL:
9-12

SUBJECT AREA:
Astronomy/Space

CREDIT:
Don DeMember, science resource teacher, Kingsview Middle School, Germantown, Maryland.

OBJECTIVES:
Students will understand the following:

1. There are three different types of nuclear reactions.

2. Most of the sun's energy is produced during nuclear fusion, in which the union of atomic nuclei from two lighter atoms (hydrogen) unite to form a new heavier atom with smaller mass (helium). The “extra” mass is converted into energy.

3. Fusion reactions should be distinguished from fissionreactions, which produce energy in most nuclear power plants.

4. Radioactive decayis a third type of nuclear reaction, which involves atoms that undergo radioactive (alpha, beta, and gamma) decay.

MATERIALS:
For this lesson, you will need:

Research materials on nuclear reactions

Computer with Internet access

PROCEDURE:

1. Review with your students what they know about the three types of nuclear reactions—fusion, fission, and radioactive decay. They should know that most of the sun's energy is produced during nuclear fusion reactions, which convert hydrogen atoms into helium.

2. Have students use the Internet or other sources to investigate the reactions that occur in fusion, fission, and radioactive decay reactions. Two sites at which to start are the ABC's of Nuclear Science page at nsd.lbl and a nuclear chemistry page available at library.

3. Have your students use these and other resources to complete a three-part Venn diagram comparing and contrasting fusion, fission, and radioactive decay.

4. Divide your class into groups, assigning each group one of the three reactions to investigate more thoroughly.

5. Each group should prepare a presentation that includes a three-dimensional model illustrating how its assigned reaction works.

6. Each presentation should also include an explanation of each reactant and product and the way in which energy is released.

7. Have students give their presentations and compare and contrast their models.

ADAPTATIONS:

Have students research the sun to find out how it produces solar energy. Have them also research how nuclear energy is produced in nuclear power plants. In class, discuss the similarities and differences between the two types of energy production.

DISCUSSION QUESTIONS:

1. What would happen if the amount of light reaching the Earth from the sun were cut in half? Predict what the climate and life would be like here on Earth. How would humans respond to this change?

2. Most of the sun's energy is produced from fusion reactions, while nuclear power plants use fission reactions to produce their energy. Compare and contrast nuclear fission and nuclear fusion. Name at least three ways they are similar and three ways they are different.

3. Solar flares can cause damage and disruptions to communication systems. If the sun experienced a prolonged period of solar flare activity, what effects would we notice on Earth? How might such an occurrence affect our everyday lives?

4. The use of solar energy has not caught on like many people had envisioned when it became popular in the 1970s. What are some of the drawbacks to using solar energy as a primary source of energy in homes and businesses, and how could they be overcome?

5. The scientific community has spent billions of dollars to create an underground facility for collecting data on the neutrinos that rain down on Earth from the sun. Are the potential benefits of understanding neutrinos worth such a large expense? Why or why not?

6. Binary star systems have two stars that revolve around each other. How might life be different on a planet revolving around a binary star system instead of a solitary star like our sun?

EVALUATION:

You can evaluate your students on their diagrams, models, and presentations using the following three-point rubric:
Three points:diagram effectively compares and contrasts the three types of nuclear reactions; model clearly and accurately illustrates how group's assigned reaction works; presentation clear, well organized, and reflects excellent speaking skills
  
Two points:diagram adequately compares and contrasts the three types of nuclear reactions; model lacks clarity; presentation clear but speaking skills lacking
  
One point:diagram inadequate; model lacks clarity; presentation clear but poorly organized; speaking skills lacking
  
You can ask your students to contribute to the assessment rubric by determining which comparisons and contrasts the diagram should demonstrate.

EXTENSION:

We're Having a Heat Wave
Students will learn about the reflective and insulating properties of certain materials as they work in small groups to design and build a solar oven (using only items found in an average home) that is powerful enough to cook an ordinary hotdog. The solar oven must be no larger than 30 centimeters on each side (or a different size, if you prefer) and should not be made of materials that may easily catch on fire. (The U.S. Department of Energy's Energy Efficiency and Renewable Energy Network Web site at eren is an excellent resource. It includes a sample of what one solar oven made out of a pizza box might look like.) If available, you can use a high-temperature thermometer or meat thermometer to measure the temperatures produced by the ovens. (Since hotdogs are precooked, there is little risk of not cooking them long enough or at a high enough temperature.) When ovens are complete, you can take your students outside on a sunny day to test their creations and enjoy a solar-powered picnic.

My Life as an Atom
In this activity, students will learn about the life cycle, characteristics, and processes of our sun by writing a “biography” of an atom of hydrogen “living” inside the sun. Each student's biography should include a description of at least one of the nuclear reactions involving hydrogen in the star, descriptions of the forces (such as magnetism or high temperature) that influence the atom's activity, and a description of what happens to the atom during at least two solar events (such as a sunspot, prominence, or solar flare, or fusing with another hydrogen atom into a helium atom). Students will need time to research before they begin writing. A good resource is the Windows to the Universe Web site at windows. (Click “What's New”; then click “Sun” at the bottom of the page.) As a prewriting activity, have students create an idea web or other graphic organizer using the information they have gathered. When their writing is complete, have students share their “biographies” with the class.

SUGGESTED READINGS:

When the Sun Dies
Roy A. Gallant. Marshall Cavendish, 1998.
This book offers a comprehensive look at the sun, from its beginning as a protostar to its profound impact on Earth, both now and in the future. The work of early astronomers is identified and explained in conjunction with recent satellite observations and subsequent scientific discoveries. Black-and-white photos, diagrams, a bibliography, a glossary, and an index add to the book's usefulness.

“SOHO Reveals the Secrets of the Sun”
Kenneth R. Lang. Scientific American,Spring 1998.
Since Valentine's Day 1996, the Solar and Hemispheric Observatory has returned thousands and thousands of photos to the Earth that help us understand the sun's magnetism, solar winds, and corona in new, clear ways. This article uses graphs, color photos, and diagrams to outline these new ideas.

WEB LINKS:

The Sun (from the Nine Planets)
The complete online introductory reference on the Sun with text, pictures, data, and multimedia presentations. 
http://www.deepspace.ucsb.edu/ia/nineplanets/sol.html

Sunspots and the Solar Cycle
Get ready for the next sunspot maximum which is predicted to occur in the year 2000. Information on the history of the sunspot cycle, its effect on Earth and life, and real time data on the Sun's current activity with live photographs, provide great ideas for original student research projects. 
http://www.sunspotcycle.com/

Today's Space Weather
NOAA provides space weather alerts and warnings to the nation and the world for disturbances that can affect people and equipment working in space and on Earth. 
http://sec.noaa.gov/today.html

About Fusion
The Princeton Plasma Physics Lab provides multimedia and interactive online tutorial that relates the process of fusion on the Sun to nuclear power research with their Tokamak here on Earth. 
http://ippex.pppl.gov/ippex/About_fusion/

Surfing For Sunbeams!
Welcome to the hypermedia Tour of Our Sun! This website invites you to learn about the Sun along with the scientists who are studying our Sun at this very minute. 
http://www.lmsal.com/YPOP/Spotlight/Tour/

VOCABULARY:

aurora
A luminous phenomenon that consists of streamers or arches of light appearing in the upper atmosphere of a planet's magnetic polar regions and is caused by the emission of light from atoms excited by electrons accelerated along the planet's magnetic field lines.
Context:
The aurora borealis forms a spectacular ribbon of light in the sky.

electromagnetic
Of, relating to, or produced by magnetism developed by a current of electricity.
Context:
You can lose AM radio signals on your car radio when they are interrupted by the strong electromagnetic field that is produced around high-voltage power lines.

fusion
The union of atomic nuclei to form heavier nuclei resulting in the release of enormous quantities of energy when certain light elements unite.
Context:
In the sun, helium is produced by the fusion of hydrogen atoms.

nebula
Any of numerous clouds of gas or dust in interstellar space.
Context:
On a clear night, the Orion Nebula is visible even with the naked eye.

neutrino
An uncharged elementary particle that is believed to be massless or to have a very small mass, that has any of three forms, and that interacts only rarely with other particles.
Context:
Even though we cannot see or feel them, trillions of neutrinos hit the Earth every second. 

plasma
A collection of charged particles containing about equal numbers of positive ions and electrons and exhibiting some properties of a gas but differing from a gas in being a good conductor of electricity and in being affected by a magnetic field.
Context:
Millions of tons of electrically charged plasma may be thrown out into space after a solar disturbance. 

prominence
A mass of gas resembling a cloud that arises from the chromosphere of the sun.
Context:
A large, looping prominence on the surface of the sun can be detected here on Earth about eight minutes after it occurs.

radiation
The process of emitting radiant energy in the form of waves or particles.
Context:
Exposure to ultraviolet radiation has been linked to skin cancer in humans.

ACADEMIC STANDARDS:

Grade Level:
6-8
Subject Area:
nature of science

Standard:
Understands the nature of scientific inquiry.

Benchmarks:
Benchmark: 
Uses appropriate tools (including computer hardware and software) and techniques to gather, analyze, and interpret scientific data. 
Benchmark: 
Understands the nature of scientific explanations (e.g., emphasis on evidence; use of logically consistent arguments; use of scientific principles, models, and theories; acceptance or displacement based on new scientific evidence).

Grade Level:
6-8, 9-12
Subject Area:
physical science

Standard:
Understands energy types, sources, and conversions, and their relationship to heat and temperature.

Benchmarks:
Benchmark 6-8: 
Knows how the sun acts as a major source of energy for changes on the Earth's surface (i.e., the sun loses energy by emitting light; some of this light is transferred to the Earth in a range of wavelengths including visible light, infrared radiation, and ultraviolet radiation). 
Benchmark 6-8: 
Knows that heat can be transferred through conduction, convection, and radiation; heat flows from warmer objects to cooler ones until both objects reach the same temperature. 
Benchmark 6-8: 
Knows that most chemical and nuclear reactions involve a transfer of energy (e.g., heat, light, mechanical motion, electricity). 
Benchmark 9-12: 
Knows that although the total energy of the universe remains constant, matter tends to become steadily less ordered as various energy transfers occur (e.g., by collisions in chemical and nuclear reactions, by light waves and other radiations), and the energy tends to spread out uniformly. 
Benchmark 9-12: 
Knows that nuclear reactions convert a fraction of the mass of interacting particles into energy (fission involves the splitting of a large nucleus into smaller pieces; fusion is the joining of two nuclei at extremely high temperature and pressure) and release much greater amounts of energy than atomic interactions. 

Grade Level:
9-12
Subject Area:
physical science

Standard:
Knows the kinds of forces that exist between objects and within atoms.

Benchmarks:
Benchmark:
Knows that magnetic forces are very closely related to electric forces and can be thought of as different aspects of a single electromagnetic force (moving electric charges produce magnetic forces and moving magnets produce electric forces); the interplay of these forces is the basis for electric motors, generators, radio, television, and many other modern technologies. 
Benchmark: 
Knows that nuclear forces are much stronger than electromagnetic forces, which are vastly stronger than gravitational forces; the strength of nuclear forces explains why great amounts of energy are released from the nuclear reactions in atomic or hydrogen bombs, and in the sun and other stars.

Grade Level:
9-12
Subject Area:
nature of science

Standard:
Understands the nature of scientific knowledge.

Benchmarks:
Understands how scientific knowledge changes and accumulates over time (e.g., all scientific knowledge is subject to change as new evidence becomes available; some scientific ideas are incomplete and opportunity exists in these areas for new advances; theories are continually tested, revised, and occasionally discarded).

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