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Lesson:
Composition of Solar Wind(Grades 10-12)
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Teacher Information
The changing position of a comet's tail as it circumnavigated the sun lead observers to predict a "solar wind," something blowing out from the sun causing long streamers behind the comet just as a strong wind causes long hair to blow away from a face. This wind was confirmed in 1959 by the Soviet Luna 3 spacecraft and has been the object of study ever since.
The solar wind consists of charged particles, mainly protons and electrons, emanating from the Sun in all directions at speeds of several hundred kilometers per second. The solar wind also contains, in much smaller amounts, positive ions stripped of many of their electrons by the extremely high temperatures of the Sun.
This lesson, in multiple steps, prepares students to analyze actual data from SOHO, in particular from the
CELIAS (Charge, ELement and Isotope Analysis System) and EIT(Extreme-ultraviolet Imaging Telescope) instruments on the spacecraft. CELIAS has measured elements and isotopes that were not observable or not resolvable from more abundant species prior to SOHO. This information is adding to our knowledge of the composition of the solar wind.
- Relative Abundances
- Wavelength of Light
- Spectral Analysis with Diffraction Gratings
- Spectral Analysis from Spectra
- SOHO Data Analysis
Activity 1: What are the Relative Abundances of the Elements?
(A review of the periodic table, appropriate for grades 10-12)
Materials:
Type of Activity:
- Lecture/Discussion
- Calculations of some relative abundances
Procedure:
- Review Periodic Table
- Names of elements.
- Isotopes (atoms of the same element with different numbers of neutrons).
- Students compare relative terrestrial abundances by inspection.
- What is the terrestrial (Earth) abundance of Al-27?
- What isotopes of Argon are present on Earth?
- ANSWER: Ar-36, Ar-38, Ar-40
- What is the primary isotope of Argon on Earth?
- Students compare abundances by division.
- How much more Ar-36 is present on earth than Ar-38?
- ANSWER: Divide Ar-36 abundance (0.34) by Ar-38 abundance (0.063) = 5.4. There is 5.4 times as much Ar-36.
- Perform several comparisons so students become proficient.
- Allow 30-45 minutes for this activity.
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Activity 2: Calculating the Wavelength of Light (Optional)
(Use of Diffraction Gratings, appropriate for grades 10-12. This activity and Activity 3 may be omitted without loss of continuity.)
Materials:
- Diffraction Gratings
- Optical bench
- Optical slit with scale and holder
- Mercury light source
- Incandescent light source
- Individual student science notebooks or paper.
- Calculators
Type of Activity:
- Laboratory
- Calculations of wavelengths of light
Procedure:
- Use a high school physics book such as "Physics: Fundamentals and Frontiers", Houghton Mifflin, as a resource.
- Measuring Wavelengths of Light Experiment
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Activity 3: Spectral Analysis of the Elements Using a Diffraction Grating (Optional)
(Use of Diffraction Gratings, appropriate for grades 10-12. This activity may be omitted without loss of continuity.)
Materials:
- Diffraction Gratings
- Several light sources
- Tungsten filament lamp
- Several gases
- Reflected Sunlight
- Fluorescent lamp
- Individual student science notebooks or paper.
Type of Activity:
Procedure:
- Use a high school physics book such as "Physics: Fundamentals and Frontiers", Houghton Mifflin, as a resource.
- Using diffraction gratings, observe the unique spectra of different elements.
- Examine REFLECTED sunlight (from a white sheet of paper) with the diffraction grating.
- Discuss the observed differences.
- Students record observations and results of the discussion.
- Questions: How do we know that there are no other elements in the universe except these?
- Spectra from the sun and
stars have revealed no other elements except those
known on earth.
- Students examine several printed color spectra of elements.
- Use a high school/college chemistry or physics book as a source.
- Spectra are unique to each atom and are used as "fingerprints" or "signatures" to identify an element.
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Activity 4: Spectral Analysis of the Elements
(Analysis of Spectra, appropriate for grades 10-12.)
Materials:
Type of Activity:
Procedure:
- Use a high school physics book such as "Physics: Fundamentals and Frontiers", Houghton Mifflin, or a chemistry book as a resource.
- Question: How do we know that there are no other elements in the universe except these?
- ANSWER: Spectra from the sun and stars have revealed no other elements except those known on earth.
- Students examine several printed color spectra of elements and discuss differences.
- Use a high school/college chemistry or physics book as a source.
- Students record observations and results of the discussion.
- Spectra are unique to each atom and are used as "fingerprints" or "signatures" to identify an element.
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(Analysis of Data from the CELIAS instrument on SOHO,appropriate for grades 10-12.)
Materials:
Type of Activity:
- Observations of Graphical Representations of Elements/Isotopes
Procedure:
- Students answer prescribed questions from the MTOF
graph (Caption
here).
- According to this graph, which only deals with mass numbers greater than 10, what elements are present in the solar wind?
- ANSWER: C, N, O, Ne, Na, Mg, Si, S, Ar, Ca, K, Ti, Cr, Fe, Mn, Ni
- Which isotopes of Argon are present?
- Which calcium isotope is present in the greatest amount?
- What are the peak heights of Ne-20 and Ne-22?
- ANSWER: Ne-20: approximately 340; Ne-22: approximately 70. (From the 100 mark, count backwards by 10s, because these are logarithmic scales. The first tic mark above the origin is actually 30. This is a good exercise to get students used to seeing how data is actually reported.)
- Using the second and third graphs of 16-18 Feb 1996, which are more expanded versions of the previous graph that show the peaks more clearly, what sulfur isotopes are present?
- What are the peak heights of Fe-54 and Fe-56?
- ANSWER: Fe-54: approximately 260; Fe-56: approximately 3500. (Each tic mark represents 1000.)
- How do these abundances compare to those on earth, observed in Activity 1?
- Because each isotope is represented by a distribution curve which overlaps others at the base, it is not feasible using high school math to decide exactly how much of a given isotope is actually present. We can, however, use these graphs to indicate approximate quantities, teach the reading of peak heights on the logarithmic scale, and show a graphical interpretation of the actual raw data being collected from a satellite.
- Student literature research project:
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Connections to National Standards:
- National Science Education Content Standard A, B, D, E, H:
- All students should develop abilities necessary to do scientific inquiry.
- All students should develop an understanding of structure of atoms, structure and properties of matter, motions and forces.
- All students should develop an understanding of origin and evolution of the earth system.
- All students should develop understanding about science and technology.
- All students should develop understanding of science as a human endeavor and historical perspectives
- Benchmarks for Science Literacy:
- Students should know that telescopes collect information from across the entire spectrum of electromagnetic waves, space probes send back data from the remote parts of the solar system and that increasingly sophisticated technology is used to learn about the universe.
- Standards for School Mathematics:
- Students should estimate, make and use
measurements to describe and compare phenomena;
select appropriate units and tools to measure to
the degree of accuracy required in a particular
situation; develop formulas and procedures
for determining measures to solve problems.
Created by: Ginger Sutula
Direct Comments to: vsutula@umd5.umd.edu