Index of Soho Lesson Plans

Differential Rotation of the Sun
Coronal Mass Ejection Velocity with NIH Image
Convection Cells

Modeling the Sun

MATERIALS

ENGAGEMENT

Grades K through 2

Grades 3 through 4

Grades 5 through 6

EXPLORATION

The diameter of the Sun is 109 times the diameter of the Earth and the distance is 93 million miles between Earth and the Sun. Ask students to estimate the size of the Sun relative to the size of Earth and the distance between the two.

Grades K through 3

Grades 4 through 6

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EXPLANATION

Models are tools to explain relationships and phenomena too large or abstract to be seen. Rockets are used to launch the satellites and probes that gather information about our solar system and beyond.

Grades K through 3

Grades 4 through 6

ELABORATION

The Sun has been an object of art through the ages.

EVALUATION

OBJECTIVES

CONNECTION TO THE
NATIONAL SCIENCE STANDARDS

Grades K through 4

Grades 5 through 8

CONNECTION TO THE
NATIONAL MATH STANDARDS

Grades K through 4

Grades 5 through 8

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TheSun has been an object of art through the ages.

"Starry Night" by
Vincent Van Gogh.

 

Lesson: Differential Rotation the Sun (Grades 9-12)

Teacher Information

The Sun has a north and south pole, just as the Earth does, and rotates on its axis. However, unlike Earth which rotates at all latitudes every 24 hours, the Sun rotates every 25 days at the equator and takes progressively longer to rotate at higher latitudes, up to 35 days at the poles. This is known as differential rotation.

The Sun rotates in the same direction as Earth. The Carrington Rotations are named for Richard Carrington, an astronomer who first noted that sunspots rotate every 27.28 days. Rotations are numbered starting with 9 November 1853. The 1996 June 18 – 1996 July 15 rotation is rotation number 1924.

This lesson uses SOHO data from the EIT(Extreme-ultraviolet Imaging Telescope) instrument on the spacecraft.

Activity: Longitude and Latitude

(You should become familiar with locating positions on a sphere, appropriate for grades 9-12)

Materials

• Globe indicating longitude and latitude lines
• Printouts of EIT images and a NOAO spherical grid
• Individual student science notebooks or paper

Type of Activity

• Lecture/Discussion
• Location of places on Earth
• Plotting active regions on the Sun

Procedure

1.Review longitude and latitude.

• Locate places on a globe, given longitude and latitude.

2.Make connection from Earth to Sun.

• The Sun is described by longitude and latitude lines.
• Introduce Carrington Rotation.
  • A numbering of rotations starting from 1853.

3.Given a seven-day sequence of EIT images, plot two active areas on a solar grid.

• A good set of data is that of Aug. 24 - 30, 1996, where two clear sets of solar activity are visible, one at -10 latitude and one at -30 latitude
• Once the seven images are retrieved, print out the solar grid. Note that the grid has 36 divisions. (Remember that the Sun is spherical: 18 in front and 18 in back. Some are closer together than others, due to perspective, but all are equal)
• By holding the grid over the image up to the light, or on an overhead projector, students can mark sequential locations of these active regions
  • For the -10 latitude active region, days 27-30, the spot has traveled 4/36 (1/9) of the distance around the sun in 3 days. Therefore its projected time of rotation at -10 latitude is 9x3 = 27 days
  • For the -30 latitude region, from day 24 to day 29, the spot passes through 6/36 (1/6) of the solar sphere in 6 days. Therefore, its projected time of rotation at -30 latitude is 6x6 = 30 days.

4.Independent Student Research: Study images of the Sun for a period of 2 - 3 months, track active regions at different latitudes, and calculate differential rotations.

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Connections to National Standards:

• National Science Education Content Standard A, B, D, E, H:
  • You should develop abilities necessary to do scientific inquiry
  • You should develop an understanding of motions and forces
  • You students should develop an understanding of origin and evolution of the Earth system
  • You students should develop understanding about science and technology
  • You students should develop understanding of science as a human endeavor and historical perspectives
• Benchmarks for Science Literacy:
  • You 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:
  • You 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

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Teacher information

The Solar and Heliospheric Observatory (SOHO) has been sending back amazing new information about the Sun. This information includes data on coronal mass ejections or CMEs. CMEs are not totally understood but appear to be material ejected from the Sun by the apparent loss of magnetic continuity holding high-energy particles on the Sun. When this breakdown occurs, the material is thrown away from the Sun as a type of solar wind.

Using an image taken by the LASCO instrument on board the SOHO spacecraft, along with a shareware program for image processing, we will investigate the acceleration of a CME into space. Questions to answer include: what are the velocity and acceleration of a CME? Does it accelerate uniformly away from the Sun?

A version of this exercise done with only paper and pencil can be found here.

Objectives

1.To demonstrate a scientific strategy for determining the acceleration of material away from the Sun
2.To formulate appropriate equations to support their strategy
3.Demonstrate the ability to use image software from the net
4.Demonstrate the capability of moving data from one program to another
5.To synthesize a best conclusion based on their findings.

Materials:

• A computer with the specifications needed to run NIH Image
• A copy of NIH Image on the computer
• Software on the computer to create spreadsheets
• Software in the computer to create reports (optional)
• LASCO images of a CME
  (If you do not know the procedure for bringing down an image off of a web page, go to "Procedure: Bringing down an image," which immediately follows this sentence)

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Procedure

A. Bringing Down An Image

1.Go to the CME LASCO image on the SOHO pages at http://sohowww.nascom.nasa.gov/explore/rdat_cme_imgs.html
2.Click and hold on the first image. A window will open. Move the curser to save this image as... and release. Save this image in a place on your computer that you will be able to access easily. It would also be a good idea to name the image just in case you will need to search for it.

B. The Activity: Make sure that you have the NIH Image in your computer as well as a spreadsheet program. If you are working with students, it would be a good idea to have a program such as Lotus 1-2-3 or ClarisWorks that will allow the students to print reports using different programs. These programs have spreadsheets as well as word processing programs that will allow easy transfer from one type to another.

1.Open NIH Image.
2.Go to the ANALYZE menu and pull down to OPTIONS. You will get this screen.

3.Click the boxes for AREA and PERIMETER/LENGTH. Click OK.
4.Using FILE from the pulldown menu, select OPEN.
5.Open the first LASCO image of the CME that you downloaded from the SOHO website. (NOTE: The image must be in PICT or GIF format. This may mean opening the image with a translator program and then saving it under one of these formats)
6.Note that at the bottom of the image there are white tick marks. These marks show the diameter of the Sun. It is possible to print this image and do the work by hand. Select the measuring tool, and starting from the center of one white tick mark, click and drag to the center of the next tick mark. (if you hold the shift key down, it will automatically draw a straight line)
7.Go to ANALYZE and then to SET SCALE. The following window will open.

8.The measured distance is in pixels as seen by the units. If you click on Pixels next to Units you can choose the units you wish. We would suggest that you choose kilometers.
9.In the Know Distance Box (that should be highlighted) type in the diameter of the Sun in kilometers. This distance is 1,392.000. Click OK.
10.Move the curser (measuring tool) to the edge of the occulted area and draw a line to the edge of the CME.
11.Go to ANALYZE, then MEASURE. When you release the mouse on measure it will automatically measure and scale the distance along that line. It will also measure the area of the line. This can be adjusted later.
12.Next go to OPTIONS, then THRESHOLD. The color of the screen will change and the LUT (look up table on the side) will change to black and white. Your curser will also change to a "+". By moving the black bar along the LUT you can change the color of the pixels to black. You will notice that at one point the CME will be white while all of the background will be black.
13.Chose the wand tool (it looks just like a magic wand) and click along the outside edge of the CME until "dancing ants" surround the gas ball.
14.Go to ANALYZE, then MEASURE.
15.Open the next image and redo steps 10 through 14.
16.Once all of the images have been processed, go to ANALYZE then SHOW RESULTS. When you go to ANALYZE, and SHOW RESULTS you will see a screen like this:

The first number is the area of the line and the second is the distance along the line. Remember that the first measurement you took was the length of the line and the second was the area of the expanding gas. We therefore do not need the first area and the second length. As stated before, we will change this later. Note that your numbers will not be the same as above.
17.Go to FILE, then SAVE AS. Select measurement from the buttons and save.
18.Open the above file with a word processing program. Go to EDIT then COPY MEASUREMEMTS.
19.Open your spreadsheet program and paste the results of the measurements. This is where you will have to delete the measurements that you don't need. (see step 16).
20.Using the instructions for your spreadsheet program, make a table that will show acceleration of the CME away from the Sun as well as the acceleration of the area of the CME.

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MEETING THE STANDARDS

How does this exercise meet national education standards?

The following information was taken with authorization from:

Content Knowledge: A Compendium of
Standards and Benchmarks for K 12 Education
John S. Kendall and Robert J. Marzano

Mid-continent Regional Educational Laboratory, Inc. 1996

Mid-continent Regional Educational Laboratory, Inc.
2550 South Parker Road, Suite 500
Aurora, CO 80014
http://www.mcrel.org/

Standards for Mathematics

Understands and applies basic and advanced properties of the concept of measurement

• Has a basic understanding of the concept of velocity and how it is measured
• Has a basic understanding of the concept of acceleration and how it is measured
• Determines precision and accuracy of measurements
• Understands that scale drawings can help one measure distances and angles that are inconvenient to measure directly.

Science and Technology

Understands the nature of scientific knowledge

• Knows that science distinguishes itself from other ways of knowing and from other bodies of knowledge through the use of empirical standards, logical arguments, and skepticism, as scientists strive for certainty of their proposed explanations
• Knows that scientific explanations must meet certain criteria; they must be consistent with experimental and observational evidence about nature; and they must include a logical structure, rules of evidence, openness to criticism, reporting methods and procedures, and a commitment to making knowledge public
• Knows that because all scientific ideas depend on experimental and observational confirmation, all scientific knowledge is, in principle, subject to change as new evidence becomes available; in areas where data, information, or understanding is incomplete, it is normal for scientific ideas to be incomplete, but this is also where the opportunity for making advances may be greatest.

Understands the nature of scientific inquiry

• Designs and conducts scientific investigations by identifying and clarifying the question, method, controls and variables; organizing and displaying data; revising methods and explanations; presenting the results; and receiving critical response from others.

Based on an activity in Sun Centered Physics, a set of lesson plans developed by Linda Knisely.

Created by: Dennis Christopher
Direct Comments to: dennis.christopher@gsfc.nasa.gov

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Lesson: Convection Cells (Grades 9-12)

Purpose

To produce a visual convection current in the classroom and compare it to the images taken of convection cells in the Sun.

Teacher Information

Convection is the transport of energy due to density differences when not in a free-fall (microgravity) environment. As a liquid or gas is heated it expands and becomes less dense and therefore lighter. If a cooler denser material is above the hotter layer, the warmer material will rise through the cooler material to the surface. The rising material will dissipate its heat (energy) into the surrounding environment, become more dense (cooler), and will sink to start the process over.

The source of the Sun's energy is the nuclear reactions that occur in its core. There, at temperatures of 15 million degrees Kelvin, hydrogen atom nuclei, called protons, are fused and become helium atom nuclei. The energy produced through fusion in the core moves outward, first in the form of electromagnetic radiation called photons in the so-called radiative zone. Next, energy moves upward in photon-heated solar gas. This type of energy transport is convection. Convection motions within the solar interior generate magnetic fields that emerge at the surface as sunspots and loops of hot gas called prominences. Most solar energy finally escapes from a thin layer of the Sun's atmosphere called the photosphere, which is the part of the Sun observable to the naked eye. Convection cells can be seen on the surface of the Sun like the image that follows.

The activity is a simulation of this image.

Activity: Displaying Convection

Materials

• A hot plate
• A small sauce pan, beaker or glass pie pan
• Rheoscopic fluid* or apple cider

Type of Activity:

• Teacher demonstration

Procedure

1.Place the container with the fluid on the hot plate on the lowest setting.
2.Within a couple of minutes you should see a reaction. If the reaction starts to dissipate, increase the heat by a very small amount.

Questions

1.Why does the reaction dissipate?
2.Would this dissipation happen on the Sun? Why?
3.Does your observation of the simulation coincide with the image above?
4.Remembering why convection occurs, would this occur in a microgravity (free-fall) environment?

Related links

Study a granulation image and take the granulation quiz at the Stanford Solar Center
Teaching Convection

Connections to the National Standards:
(Grades 9-12)

• Understand energy types, sources, and conversions, and their relationship to heat and temperature
• Know that energy tends to move spontaneously from hotter to cooler objects by conduction, convection, or radiation; similarly, any ordered state tends to spontaneously become less ordered over time.

*NOTE - apple cider will work for this activity but a better material is Rheoscopic Fluid by Novostar Designs, Inc., Burlington, N.C. 1-800-659-3197. The listing of the proprietary name in this section is not an endorsement of the product. The company name listed is only a suggestion.

Created by: Dennis Christopher
Direct Comments to: dennis.christopher@gsfc.nasa.gov

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