Final Lesson: The Electromagnetic Spectrum. A connection between Astronomy and Chemisty

Introduction

Making connections between two major branches of science when teaching middle school  can be a challenge.  Making these connections helps students link their lives to everyday science and its phenomena. 

Starry Night software program.  The sky looking North at 20:37 Dec 29th from Indian, AK

Before starting a unit on chemistry, I make sure I end my Astronomy unit with stars and constellations of the Northern sky.  The study of stars is a great place to introduce elements and the chemical interactions that make up the 8th grade curriculum.

This is a photo taken by the X-Ray Telescope (NASA) of an exploding star

  The following lab engages middle school students in an exercise involving astronomy, chemistry, and a cultural connection to the stars.

Background

The light radiating from the stars in the sky can be visible and invisible to the naked eye.  This energy is known as electromagnetic radiation.

The Electromagnetic Spectrum.  Graphic from http://www.kollewin.com/blog/electromagnetic-spectrum/

The light we can see is only one type of electromagnetic radiation.  Stars can give off radiation you can’t see such as radio or ultraviolet light.

Electromagnetic radiation can be broken into ranges based on the size of their wavelength.  All of the different types of electromagnetic waves make up the electromagnetic spectrum. 

Light will travel in waves and those waves have troughs and peaks that are long or short depending on the energy.  This spectrum can tell astronomers the temperature and even the composition of the stars.

Astronomers not only use visible light telescopes but radio and x ray telescopes to capture and analyze the energy from distance stars.

http://www.pa.uky.edu/sciworks/physicspettingzoo/Spectroscope.htm

Astronomers use a tool called a spectroscope to capture visible light and break it into a spectrum that can be analyzed for the presence of different elements.

http://webmineral.com/help/FlameTest.shtml

 

As you can see from the spectrogaph, each element has a specific wavelength, or fingerprint, of light.  Most light (visible), can be separated into component wavelengths.  This separation is from the spectroscope’s prisms or diffraction grating.  Of the three types of spectra:  continuous, emission, and absorption, the last two can be used as “fingerprints” in the identification of elements. 

Each element in its gaseous form will give off light in definite wavelengths.  Elements and compounds can be identified by the light they absorb through  bright lines in the spectrum. These are measured in Angstroms, through the Spectroscope (see example). 

The lab

Flame Test, Spectroscopes, and Stars

Photo by author

Question:            How can we determine the metals in certain solutions?

Purpose:            To understand that metals lose energy in the form of light and this light can be broken up into a spectrum resulting in different wavelengths that can be analyzed  into a known line spectrum of different elements.

Materials:             

• Bunsen Burner             
• Test Tubes (6)                                     
• Test tube rack                                         
• Goggles                       
• Nichrome wire                                   
• 5 metal solutions
• HCl solution               
• distilled water                                     
• spectroscope

                                                                               

 Procedure:     1.  Label the test tubes A – E

2.     Pour 5ml of from each of the labeled solutions into corresponding labeled test tube.

3.     Clean the nichrome wire by dipping it into the HCl solution provided to you and then the distilled water and drying it in the Bunsen burner.  Repeat until the wire doesn’t color the flame form the Bunsen burner.

4.     Dip the clean wire into one of the labeled test tubes solutions.  Hold the wire at the inner cone of the flame.  Record color and any other observations in the data table.

5.     Using the spectroscope, find the metal’s spectrum by looking at the flame.  Look for any dark lines and note what color they are in.

6.     Diagram your spectrum or use the textbook (page 100, Fig 4) to find the element’s line spectrum.

7.     Repeat steps 2-4 for the other chloride solutions.

8.     Please rinse out all test tubes and clean your area.

Data:

Test Tube	Color	Solution
A
B
C
D
E

Conclusions:            If your test solution was a mixture of two metal ions, could you identify both?  Try it.  Try the spectroscope and see if you can see two different lines.

Photo by author

Questions

            1.  What is a spectrum?  How is a spectrogram useful in studying stars?

            2. Why is it necessary to clean the wire between each test?

           

3.  Some flame tests were very apparent in the color produced while others were more vague.  What do you think are some reasons that could account for this?

            4.  How do the samples resemble stars?  How can scientists tell what elements are in a distant star?

            5.  Diagram the Bunsen Burner equipment and show a correct flame.  Label all parts.  Color is an option.

Enrichment

The lab is a fun way to explore why stars give off light in different colors and a lot of students feel they are doing "real" science.  The problem is sometimes its hard to see through the spectroscopes and see any prisms especially the lines.  Other labs use different types of lamps and lights to find known elements and using one of these would be a great demonstration or lab on its own.

The Discovery video collections have great videos as we well know.  My favorites are the ones  we have already used in this class and I plan on using them in mine!

Another video that gets the kids excited about chemistry is KABOOM!.  The interaction of different elements makes for cool chemistry.

http://www.teachersource.com/Chemistry/ChemistryResources/KABOOM_NovaVideo.aspx

Cultural connection

There are many stories about the stars and the patterns they make in the sky.  Ancient Greek and Roman stories abound.  But other cultures have stories that would interest most middle school students.  The  Alaskan natives for example have several stories of the strange lights that appear in the sky. These stories can be used as introductory lessons to get the students thinking about the constellations and a spark for their imagination in making up their own stories of the stars.

I especially love the stories of the Northern Lights and have heard several versions of the gods in the sky playing kickball with a skull.  Many elders I have known are still afraid of the
Aurora.

The state flag of Alaska is also a great introduction of the night sky and connections to Native Alaskans.  

Conclusions
I have done the flame test lab several times as a demo and as a real lab.  By using the new resources on the web and our own video library at Discover, I think this lab activity will help middle school students grasp the connection between the different branches of science and allow them to make these connections on their own through life long learning.  

Please feel free to email me to get the word flame test document and feel free to use it and modify it for your classroom.  mittelstadt_konrad@asdk12.org

Its been a great class have a great New Years........

References

Pasachoff, J. M.,  Astronomy Prentice Hall, Nedham, Mass 2000.

http://imagine.gsfc.nasa.gov/docs/science/how_l1/spectra.html

http://webmineral.com/help/FlameTest.shtml

http://www.trschools.com/staff/g/cgirtain/Weblabs/spectrolab.htm

http://www.wwu.edu/depts/skywise/legends.html

http://starryskies.com/articles/dln/5-97/native.myths.html

http://www.angelfire.com/ca/Indian/WhyStars.html

http://www.museums.state.ak.us/eightstars/resources_bibliography.html

http://www.ewebtribe.com/NACulture/articles/aurora.html

http://imagine.gsfc.nasa.gov/docs/dictionary.html#S

http://www.astrosociety.org/

http://www.exo.net/~pauld/summer_institute/summer_day9spectra/spectra_exploration.html

http://www.stsci.edu/portal/

http://imagine.gsfc.nasa.gov/docs/teachers/lessons/roygbiv/roygbiv.html

Module IX Tales of Drunken Trees, Methane Bombs & Glacier Blues

 The Learning

Viewing the TD videos allowed me to gather valuable information on the module’s topic this week.  I found them to be full of great photography and content for students to see first hand. 

The pictures of “drunken trees” and the stories of lakes disappearing around Huslia was quite an eye opener.  I found it a little ironic of the talk about decreasing the use of fossil fuels to help combat this problem but in the next scene, kids and adults are cruising around the village on snow machines or four wheelers.  You can’t take the outboard off the boat if you are going up river?!

The thawing of ice-rich permafrost causes subsidence of the land surface, creating thermokarst ponds and causing trees to tilt, which is shown in this peatland terrain in Churchill, Manitoba.  Photo by USGS

This changing arctic landscape  increases the threat of fire and new species of trees are showing up that have never been seen before.  That’s scary.

Permafrost is any rock or soil that has remained under 32˚ degrees F for over 2 years.  The Bank Island video showed many images of thawing permafrost. They estimate by 2100, the permafrost will be thawed to 11 feet. Ouch!

The interactive Mountain of Ice video showed sea levels 20000 years ago that were 400 feet lower than today.  What ancient villages are off the coast of the United States?  Submersibles should be scouring the bottom for more clues!

The rest of the videos showed great black and white photos taken hundreds of years ago and compared them to recent photos taken in 2004.  What I found so interesting was the amount of contrast and quality those old photos still possess.  I would rather look at those old photos than the washed out digital we have today.

Since 1850, the world’s glaciers have lost 30% of their total surface area.  That’s a lot of melting. 

So the fact that the world’s temperature has risen 1 degree F the past 100 years is starting to become a big deal. 

The Doing

 

Glacier study here in Southcentral would be a great way to introduce glaciers and global warming to a group of Anchorage area students.  Isostatic rebound were their school lies in the Anchorage bowl was over 1000 feet.  Imagine that. 

So much of the topography around the Anchorage Bowl and surrounding mountains is due to glaciers.  Carving turns in the Glacier Bowl above chair 6 at Alyeska wouldn’t be possible without the cirque carved by a glacier.

Portage Glacier still provides clues on the movement of these giant masses of ice.  Here are photos of scratches left by the mass of rock and ice as the glacier moved through the Portage valley.

Portage Glacier 2007. photo by author

Scratches in nearby rocks made by glacier.  Photo by author

The best site on our module would have to be the extreme Ice survey.  The time elapse photography was amazing.  Any teacher working with curriculum that deals with erosion and glaciers should use this site.   Way cool.

Another was the methane bombs being lit by the teachers and students of UAF.  I saw this in Portage one winter and can’t wait to find some pockets of CH4 around my house to light (to the chagrin of my wife….”you are NOT bringing the kids!).

This module got me thinking on how I could explore this in the classroom.  How about finding Permafrost on other planets!  Of course NASA is already exploring that with the Phoenix.

There are also UAF resources for exploring permafrost right here in Alaska.  Google Earth and Permafrost make a great connection.

What really interested me was the isostatic rebound of the land around Anchorage.  The topography around here is a natural field trip right out the door.

From this map, you can see the various landmasses and features made by glaciers. Source http://www.alaskageography.com/essays/glaciers.htm

I have heard of rebounds in the thousands of feet but could only verify under 300 feet.  But just imagine how much rock and ice must have been on the flats to lower it even that much.

The Shameless Plug

http://www.williwaw.com/magento/index.php/weather-calendars-and-publications.html

I can't leave this weeks blog without a mention about the nice folks in Haines that put out the Alaska Weather Calendar.  I have been giving and receiving these wonderful calenders since late '95 and I can't tell you enough about how much Alaskan weather photos and facts they stuff in there.  Check out their site and check up on the winter forecast and other goodies they have.

 Stay safe and have a very cheerful Christmas Solstice.  If you are in the Indian Valley look for the bonfire to the North.  The pagans will be celebrating the longer days to come at December 21st at 2:38 pm. 

Also look for the lunar eclipse that will happen late Monday night!

The Other Voices

First stop was the wonderful site from Marilyn that turned me on to Antonio Stradivari's violin making and the wood used during Europe's little ice age.  Wow

Next I went a blogging to Bobbi-Ann's site and wondered how she could work with those fish swimming all around her page?  Thats pretty cool.

Dave's site is pleasing to the eye.  The photos in the background make it look so professional.  I also agree that the climate data out there can be interpreted so many ways and  we need to keep an open mind about the data and solutions to the problem.

Module VIII The Cryosphere

Turnagain Arm (photo by author)

“Kryos”  The Greek word for cold. 

Consists of all the frozen places on the Earth.  It is seasonal and can increase and decrease with Earth’s revolution around the Sun.

It’s made up of:  Snow

                           Ice

                           Sea Ice

                           Glaciers

                           Ice shelves           

                           Icebergs

                           Frozen ground. (Permafrost...)

Locations of the world include the North and South Pole (Arctic and Antarctica), mountain regions, and the northern climates of Russia, U.S. and Canada.

Looking for maps and an atlas?

photo from http://nsidc.org/

Still not impressed?  Watch a movie from NASA.

Other great current images can be found at The Cryosphere Today website.

For my own background, I found a website that dealt with actual research on the Cryosphere.  I found papers on the Greenland freshwater runoff to measuring albedo in the Himalayan Basin.  Yes, a little over my head but fascinating for a science teacher.

From viewing the TD videos, we saw how the Arctic climate influences those that lived there, so I wanted to find out some specific changes to the ice and snow cover and their effect on the indigenous people of Southern Greenland.

I went to the  INUIT Circumpolar Council website and found a publication that listed some of the changes local people have noticed due to the changing climate of Greenland.

• Many mentioned that local glaciers were receding- so much so that the landmarks naming these glaciers were no longer correct!
• Because of less snow cover, berries such as the Crowberry have become scarce.
• Ice cover on the beaches has all but disappeared in the winter, thus moving animals to different areas and making traveling on ice dangerous.
• The native people of Southern Greenland also have seen an increase of algae on the skin of seals and their boats.  
• (An interesting observation I have also noticed here in South-central. My roof is covered in moss and algae as is the north sides of the cottonwoods around my house.  More so than any other year.)

Permafrost has always facinated me and seasonal frozen ground has always been a struggle especially when digging the biannual outhouse hole out at camp.....

photo from the virtual tunnel tour http://permafrosttunnel.crrel.usace.army.mil/

As a kid, I got the chance to tour the permafrost tunnel up in Fairbanks and the experience has left some special memories for me.  We went from 80 degrees to long underwear weather in a matter of seconds into this cave where frozen boulders looked to topple over on us at any moment to preserved animal remains thousands of years old.

Evaluate

I am looking into using vernier probes more in the classroom , (I just wish I had newer laptops).  The activity looking at white and black paper and how they might influence the temperature of a liquid could easily be modified using temperature probes.   

Beginning of the year scientific method activities using probes and the concept of albedo would make for some exciting discoveries for new eighth graders.  Comparing the reflected light of different surfaces would allow my students a great hands on activity for exploring this concept.

The TD diagram on Arctic Sea Ice Observation  would also let students use data to compare the area and square kilometers of the ice pack for the past ten years.  STEM should be all over this.

The tour of the Cryosphere was one of the best tools for students to see the different locations and extent of the Earth's frozen areas.  I couldn't believe how fast the Jakobshavin Glacier was moving!  5 feet an hour!  I have grown up watching Portage Glacier move farther and farther back, and I certainly can relate to what the Greenlanders must be going through.

Here are some photos from the Portage Glacier USGS site (see above) that shows the receding glacier from when I was seven years old, to graduating from high school, to the year I became a full time teacher in Anchorage. 

1972, USGS photograph; 1984, Aeromap U.S.; 1999 and 2006, USGS photographs.

Evaluate

This module about the cryosphere was very interesting to me.  Not only for the educational tools but the wealth of information about the science out there about my favorite season of the year.  I can't wait to enjoy that frozen water on my skis in the Chugach mountains behind my house.  Sunglasses in March?  I blame the albedo....

Comments

Doug had a great module this week.  I found a book recommendation for Wohlforth's  The Whale and the Supercomputer.  

Marilyn lead me to the National Ice Center, where I found links for .kmz files for my new passion: Google Earth.

Clay was right on about Lila's site.  I found it interesting and full of relevant science.