Solar Science
How do astronomers study the Sun?

An Outreach Project of the
Stanford SOLAR Center
(https://solar-center.stanford.edu)

Paul Mortfield, John Beck
Stanford SOLAR Center
HEPL-B208, Stanford University
Stanford, California, USA, 94305-4085


NOTE: V1.1 Originally designed as part of an IDEAS grant between Stanford (SOHO/SOI) and the Chabot Observatory/Science Center to target middle school students in the Oakland School Board. Materials were made directly available to the teachers and students in Oakland. Other schools can order the kits from the Stanford SOLAR Center via email or calling (650)725-4695.

A six day introduction to Solar Science for middle school students. The purpose is to show students how astronomers study the sun. Students will be introduced to properties of light and build their own spectroscope to study the spectra of elements found in the sun. On the final day, a solar astronomer will visit the class and allow the students to look through a portable solar telescope.

The spectroscope or spectrograph is the main tool used by astronomers to study all distant objects in space. By studying the spectrum of an object (Sun, stars, nebulae, comets and galaxies), astronomers can find out about it's temperature and magnetic field. By determining an object's Doppler shift (a shift in the sprectral lines), the astronomer can calculate how fast an object is coming towards or away from us. By looking at it's spectral fingerprints, we can determine it's chemical composition. All this from a single spectrum!

There is a lot of material to cover in a short time, yet still allow the students the opportunity to explore for themselves. We've tried to simplify wherever possible and teachers should feel free to adjust this program longer if it will fit within their objectives.

Equipment Lists
Day 1: What do we know about the Sun?
Day 2: Building a Spectroscope
Day 3: Calibrate Spectroscope
Day 4: Observing Light
Day 5: Analyzing Light & View Solar Video
Day 6: Solar Astronomer Visit



Equipment list - per class

  • 1 bag assorted UV beads (approx. 240 per package) 1 bag per class.
  • Diffraction Gratings - one grating per student
  • Gas tubes and power supply (teachers sign up to borrow this from Chabot Observatory. Contact Tamara Schwarz (510) 530-3480 ext 22 to schedule.
  • Colored Pencils or thin markers. Enough for all students to share. (Red, orange, yellow, green, purple)
  • scissors, clear tape and glue sticks for building and spectroscope



    Equipment list - per student

  • Instructions to construct the spectroscope
  • string
  • Materials for construction of spectroscope (template, cardboard, gratings, etc.)
  • 1 reference chart of solar spectrum and selected gas spectra
  • 1 chart of Electromagnetic spectrum
  • 2 blank spectrum forms used to draw observed spectra

    Day 1: What do we know about the Sun?

    Overview
    This overview activity is intended as an introduction to the rest of the course and should be kept to 1/2 a class period. The 2nd half of the class will be spent gluing the spectroscope template to cardboard.

    On this day we will discuss the reasons we study sun. We will also discuss the difficulties in studying an object where we can't use our senses.

    Equipment

  • flip chart

    When scientists want to test a theory or understand how something works, they can usually do an experiment. For example, a chemist who wants to understand a chemical reaction can combine the chemicals under controlled conditions, then watch (and measure) what happens. A geologist can bring a rock sample into the laboratory and subject it to heat, pressure and chemicals and look for the reactions. Biologists studying the migration of birds can capture some specimens and tag them with radio transmitters to track their migration patterns. But how do astronomers do an experiment on the Sun? They don't. It is too big, too far and too unattainable. Even if they could, we only have one sun so we don't want it messed up.

    Ask the students - Preconceptions
    (can put answers on flip charts to hang in the classroom for the duration of the course)

  • What do we know about the Sun?
  • Why should we study the Sun?
  • How can we study most objects? [use our senses.]
  • What things they would like to know about the sun?
    The flip chart can be posted in the classroom. As the course progresses, any answers found can be added to the posted sheet. A copy of the questions can be emailed or faxed to the assigned astronomer to allow them to tailor their visit.

    Conclusions

  • We cannot use our senses to analyze very distant objects. We have to find a different method.

    Activity: Layout spectroscope
    Have each student glue a spectroscope template to a sheet of cardboard. Have students put their name on the template and let dry for next class.

    Home work: Reading Assignment
    Have the students read up on the sun to find out it's size, distance, age, temperature and other interesting facts.

    Day 2: Build a Spectroscope

    Overview
    By breaking up the light coming from the sun, we can better understand what it's made of. Here we will build an instrument that can study light rays.

    Equipment
    Materials (and gratings) for each student to construct their own spectroscope

    Activity: Build a Spectroscope
    Follow the instructions and construct the spectroscope

    Day 3: Calibrate Spectroscope

    Overivew
    Calibrate the spectroscope using the fluorescent light.

    Equipment

  • Colored pencils or markers
  • blank spectrum forms

    Activity: Finish Spectroscope
    Complete construction of Spectroscope and follow the instructions and calibrate the spectroscope using the fluorescent light. When completed, have the students draw the spectrum of the fluorescent light

    Day 4: Observing Light

    Equipment

  • Colored pencils or markers
  • Gas tubes and power supply
  • blank spectrum forms

    Activity: Draw Spectra of Gas Tubes and Sun

  • Without telling the students which gases are in the tubes, have the students draw the spectra. Takes about 10-15 minutes per gas.
  • Use gas tubes: Helium, Hydrogen, Mercury. If time left use Neon and Water.
  • Draw the spectrum of INDIRECT sunlight.
    (NEVER POINT THE SPECTROSCOPE DIRECTLY AT THE SUN!)

    Take Home Activity: draw some spectra

  • at home, draw 4 spectra from different light sources (street lights, TV, Neon signs, etc.)

    Day 5: Analyzing Light and View Solar Video

    NOTE: Leave 15 minutes at the end of this class to view the "Colors of the Sun" video.

    Equipment

  • Colored pencils or markers
  • Comparison chart of reference spectra

    Activity: Identify the gas tubes

  • Using the chart of reference spectra, have the students identify the spectra from gas tubes drawn earlier.
  • From the chart of reference spectra, have the students match spectral lines from the individual chemical elements on the chart with the dark lines in the Solar spectrum on the chart. What elements can they find in the sun?
    NOTE: The spectrum of the sun that the students draw WILL be different than the one on the reference chart. A more sophisticated spectroscope is needed to show the dark lines in the solar spectrum. We just wanted to make sure the students had on opportunity to draw a solar spectrum with their own spectroscope. They should use the one on the reference chart for any exercises.

    Conclusion

  • Lines of a spectrum are like fingerprints of the elements in the periodic table.
  • With simple equipment, students have determined some of the elements of the sun.
  • Astronomers, use this same method to study stars, comets and super novae.

    Take Home Activity: Analyze home spectra

  • Have the students try and determine the elements in the light sources they found at home. They may not be able to figure them all out. A good excuse to sue the library or web.

    Activity:

  • View the fifteen minute video "Colors of the Sun". The video shows how astronomers use equipment similar to what the students have built, (but larger and more sophisticated) to study the sun.
  • Inform students that a real Solar Astronomer will be visiting the next day bringing a special solar telescope that they can look through.
  • Hope for a sunny day.

    Day 6: Solar Astronomer Visit

    Equipment

  • 1 Solar Astronomer with Solar telescope
  • Bag of UV sensitive beads
  • some string or rawhide cord per student

    Split the class so that half are doing the UV bracelet activity while the others are viewing the sun. Then switch half way through the class period.

    Activity:
    Each student makes a bracelet with 6 UV sensitive beads and string (or rawhide). In regular indoor light, the beads remain white. In sunlight, (even near a window) the beads change color. Attempt to shield the beads with UV blocking sunglasses. What happens? Will the beads change color on a cloudy day?

    Activity: View the sun, live through the solar telescope.
    Take Home: Solar Posters, UV sensitive bracelets
    Note: Incase of a cloudy day, there are extra images of the sun on the video tape that the astronomer can explain to the class.

    Need more Gratings and Beads

  • 1 bag assorted UV beads (approx. 240 per package) 
    The UV Sensitive Beads come from:
Educational Innovations, Inc.
362 Main Ave
Norwalk, CT 06851
1-888-912-7474
www.teachersource.com
Catalog: EDI# UV-ast  (assorted colors, approx 240 beads/bag) @ $6.95 per bag)
Note: 1 bag should be enough for 30 students.
  • Diffraction Gratings
    Edmund Scientific (609) 573-6250
    Catalog # F39502 $23.60 (pkg of 25)
    Catalog # F50183 $58.00 (pkg of 80)