differential thermal calorimetry

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Subjects: thermogram, Physical Science, Science

For students of undergraduate to undergraduate grade.

Name	Garry Loveless
School	Central Gwinnett High School---
Unit Topic	Electromagnetic Waves
Grade	High School Technical Physics
	16. Investigate the properties of waves (S8P4).                                                                                                                                    16b.Identify the characteristics of electromagnetic and mechanical waves (S8P4b).                                                                                         16c. Describe how the behavior of waves is affected by medium such as air, water, and / or solids (S8P4c).                                                                                                                          16d. Analyze the relationship between wavelength, frequency, and speed (S8P4d).
Core/ Supplemental Materials	Access to computers                                                                                         The Electromagnetic Spectrum on Trial                                                 Electromagnetic Spectrum Graphic Organizer                               Electromagnetic Wave Presentation Rubric                            Electromagnetic Wave Debate
Internet Links/Resources	1. Location of The Electromagnetic Spectrum on Trial. http://cse.ssl.berkeley.edu/lessons/indiv/nellie/new_nelli_summary.html               2. Electromagnetic Tutorial. http://school.discovery.com/lessonplans/activities/electromagneticspectrum/                                                                                                                  3. Electromagnetic Data for Graphic Organizer http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html                   4. US Frequency Allocation Chart http://www.ntia.doc.gov/osmhome/allochrt.html                                           5.Federal Communication Committee                                                    http://www.fcc.gov/                                                                                                   6. Radio Communications Company, Air Waves   http://www.ofcom.org.uk/static/archive/ra/topics/maritime/airwaves/airwave2/airwaves.htm 
7. http://en.wikipedia.org/wiki/Electromagnetic_radiation 

5 – E Strategy Used
	Engage	Students will participate in a mock trial about the electromagnetic spectrum. Teacher will lead discussion after presentation to create interest, generate curiosity, and raise questions. The discussion will lead to analysis of what students know about electromagnetic waves. Introduce terms electromagnetic spectrum, radio waves, microwaves, infrared waves, visible light, ultraviolet waves, x-rays, gamma rays. Review transverse and longitudinal movement of waves as demonstrated with a slinky in a previous lesson. Explain that energy from the sun moves in transverse waves. Have students draw the movement of energy from the sun as a transverse wave.
	Explore	Students will be divided into eight groups. Each group will explore one of the eight types of electromagnetic energy in the spectrum; radio waves, microwaves, infrared waves, visible light, ultraviolet light, x-rays, gamma rays, and cosmic waves. Students will use the suggested internet sites to begin their research. They will use http://en.wikipedia.org/wiki/Electromagnetic_radiation       to further develop a presentation which includes the following information. Students will also use a rubric to guide development of the presentation.                                                            1. What are the characteristics of the electromagnetic wave including wavelength, frequency, and interesting facts?                                                                              2. Where is the electromagnetic wave located on the spectrum and how does it relate to other electromagnetic waves?                                                           3. What are the properties which place it in the position on the spectrum?                                                        4. How is the electromagnetic wave related to everyday life or in industry? Include at least 2 uses. 
5. What are the health risks involved in using this type of EM radiation?
Students will develop a presentation on their electromagnetic wave to share with the class. 
Students will tag their bookmarks from their research on http://del.icio.us/ for other groups to verify and evaluate.  
	Explain	Students will make presentations on electromagnetic waves. As presentations are made, students will complete a data table of information. Using this data table and a follow-up web site, students will complete a graphic organizer of information. Students will peruse a website posted by one of their peers to validate and post a comment.
	Extend	Students will debate whether the government should be able to control the frequency of band widths for communication. Students will use background summary and internet sites for evidence to support or refute federal regulation of electromagnetic waves.
	Evaluate	Student made product for presentation.                Teacher made rubric for presentation design and assessment of presentations by both teacher and students. Teacher monitors design and presentation by asking open-ended questions. Teacher observes as students explore and present information, making assessments of knowledge, skills, and evidence of changes in thinking.                                                        
Safety Precautions	Internet safety                                                                                             Usual classroom safety.
Differentiation Strategies for Different Learners	Resource Students:                                                                                                     *Use a table to complete data for the presentation                              *Use a table and graphic organizers during presentations to organize information                                                                                                   *Use guide cards with supportive evidence during the debate
Sequence of Activities	Students will:                                                                                           1.participate in mock trial, preview discussion, and draw diagram.                                                                                      2.develop a presentation using research on a type of electromagnetic wave in the spectrum. (rubric provided along with note taking strategies)                                                                                               3.make a presentation on a type of electromagnetic wave, complete data table and graphic organizer. Students will analyze self and others during presentations.                                                                                                 4.participate in a debate on federal regulation of electromagnetic waves using information from resources.

"ELECTROMAGNETIC SPECTRUM ON TRIAL"                                                                                                        Participants:                                                                                                                                                                                     1. Chief Judge (C. J.)                                                                                                                                                                    2. Electromagnetic spectrum (six defendants) (E. S.)                                                                                                                      3. Chief Prosecutor (C. P.)                                                                                                                                                            4. Counselor for the Defense (C. D.)                                                                                                                                             5. Witnesses for the Prosecution (W. P.)                                                                                                                                        6. Witnesses for the Defense (W. D.)                                                                                                                                                 7. Secretary of the trial (S.)                                                                                                                                                                   8. Jury (J.)                                                                     Minutes of the Trial:
•	C. J.: Today we will consider Case # 1235. Electromagnetic waves are accused of different kinds of damage. I appeal to the Honorable Jury for the impartial examination of this case in order to arrive at a just sentence. 
•	S.: Bring in the accused Family of Electromagnetic Waves. 
•	C. J.: Let us determine the personalities of the accused. Tell us your names, please. 
•	E. S.: We are a Family of Electromagnetic waves. There are six of us in our spectrum: Radio waves, Infrared waves, Light waves, Ultraviolet waves, X-rays, and Gamma rays. 
•	C. J.: Who are your parents? 
•	E. S.: James Maxwell and Heinrich Hertz can be considered our parents. In 1980s, J. Maxwell introduced us to a scientific world by creating a special theory of electromagnetism. In 1887 (unfortunately, 8 years after Maxwell's death), H. Hertz experimentally generated and detected waves using a spark-gap apparatus. He even measured our speed, which turned out to be exactly the speed of light, just as Maxwell had predicted in his theory! 
•	C. J.: Can you explain to us more clearly who you are. Give us the definition of the electromagnetic spectrum, if you will. 
•	E. S.: Electromagnetic spectrum form a "family" that includes all types of electromagnetic waves existing in the Universe. 
•	C. J.: Who has questions to the accused spectrum. The Honorable Counsel for the Prosecution. 
•	C. P.: No questions so far, your Honor. 
•	C. J.: Counselor for the Defense? 
•	C. D.: I have a question. Will the Jury take into account the fact that the parents of Electromagnetism were such famous and outstanding scientists. 
•	C. J.: The Jury will examine all facts. 
•	C. D.: Then I have no more questions at this point. 
•	C. J.: Questions to the accused family, please. 
•	J.: Where can electromagnetic waves appear? 
•	E. S.: You can meet us at home, you can find us outdoors, we can exist even in empty space! Engineers and workers, scientists and medical personnel use us for different purposes. 
•	C. J.: Before hearing this strange case, I would like to show you some telegrams, videos, and faxes. 
•	S.: A telegram from a group of scientists: W. Hershel, W. Roentgen, A.Beckerel. "We, the physicists who discovered three types of invisible electromagnetic radiation (Infrared, X-rays, and Gamma Rays), want to make a statement. Electromagnetic waves, both visible and invisible, are very important sources of information for people. When we discovered them (sometimes accidentally), we did not know what their properties were or how to use hem. We hope you will not be too harsh with our inventions." (The telegram is accompanied by a description of the experiments conducted be Hershel, Roentgen, and Beckerel.) 
•	S.: A video from H. Hertz. "I would like to remind you that only a curious and hardworking researcher can achieve success. In 1878 I proved that electromagnetic waves did indeed exist. Numerous discoveries have been made since then, and I am sure that many clever technical devices using different types of electromagnetic waves will be created in the future. This is why I would like to tell you, my young friends, that if you look closely at this wonderful family of waves you will see that their existence is a miracle and a blessing to the mankind." (The speech is accompanied by a description of the Hertz's experiment.) 
•	S.: A fax from J. Maxwell. "My name is J. Maxwell. I am a physicist and a mathematician. At the end of the 19th century I solved an interesting problem. Based on experimental data obtained by Faraday, Oersted, and other scientists, I combined electric and magnetic phenomena in my famous equations. That is why I am usually called " the stepfather of electromagnetism." I am very proud of this fact. My theory is magnificent, but it cannot exist without pure scientific experiments. I hope you will use all your knowledge and tolerance, and will acknowledge the contribution my children made to the development of electromagnetism." (Main formulas of the Maxwell's theory of electromagnetism are demonstrated before the audience.) 
•	C. J.: I think it is time to begin the trial. Please call witnesses for the prosecution. W. P. # 1, Mr. Smith. " I am a professional cook. All my life I've been using conventional stoves to prepare food. Recently the manager of our restaurant bought new microwaves ovens. This changed everything. Some members of our staff began feeling sick. I decided to make a research on microwaves. Now I know that they are members of an entire family of waves. They are considered to be the shortest radio waves. Their property is that they are absorbed by liquids. That is why we can use them to prepare food. On the other hand, we are human beings, and our bodies contain water just like the bodies of other living organisms. The result is that our bodies also absorb microwaves! I think that it is dangerous to use them very often in our everyday life, and we should put a stop to such use without further delay" 
•	W. P. # 2: "My name is Lee. I am 15 years old, and I like listening to modern music and watching TV. I spend all my money buying stereo systems, VCR's, CD players, and stuff. It means that I use various types of radio waves: long, short, FM, AM, and microwaves. I am confused about their properties and do not know which of them to use and when. They say that different types of radio waves undergo reflection, diffraction, and other transformations when they travel in space. What also irritates me is that all the equipment I use is so unreliable. There is always static and interference, signals are clear one moment and fade away the next. Radio waves are supposed to help people communicate, but sometimes I think they are bothersome rather than helpful." 
•	W. P. # 3: "My name is Fox, and I travel a lot. I like to climb mountains, to cross deserts, to take part in sea voyages. But the problem is that every time I travel I develop skin problems. No matter what I do, my skin is always red and dry. It is only recently that I understood the reason. All my problems are related to ultraviolet radiation! Our Sun is a powerful source of UV, and although the atmosphere absorbs most of the ultraviolet, the radiation still hurts people, causing not just redness of skin, but also other serious problems, such as skin cancer. It is disgusting! Something should be done about this radiation." 
•	W. P. # 4, Ms. Lakisha Thompson: " I am an amateur astronomer. I was always interested in ultraviolet radiation. I even invented a special UV detector to help me in my work. But because UV waves are readily absorbed by the Earth's atmosphere, I am unable to continue my research. I don't know how to make my detectors work. I probably should not have developed these detectors in the first place. I think ultraviolet radiation is useless as a scientific tool."                                                                                                 W. P. # 5, Mr. Smog: " I am a professional physician with considerable experience. I treated many patients for a variety of diseases. I noticed that the number of children suffering from leukemia and other types of cancer has sharply risen in the last 15 years. My colleagues tried to find the cause of this disease. We investigated hundreds of affected children in order to obtain the necessary data. We concluded that there is a direct relation between some types of electromagnetic waves (especially X-rays and gamma rays) and the incidence of these dangerous diseases. I do not know what happened to our atmosphere and its ozone layer, but more and more waves can go through it now. These waves damage and destroy living tissue, alter metabolism in humans, and even cause mutations in living cells. That is why I accuse the family of electromagnetic spectrum! We should give this phenomena a real fight! I demand it on behalf of my poor little patients. We must relieve their suffering." 
•	C. J.: I think that the prosecution was given enough opportunity to present their case. We now invite the witnesses for the defense. 
•	W. D. # 1: " My name is Tom Gardini. I am the owner of a unique automobile which is called the electric car. I am so proud of my car! First of all, I don't need to pay for gas. But the main advantage of this car is that it does not pollute the environment, because my car has no internal combustion engine or diesel engine. Its heart is an electric motor, and its lungs are solar panels that convert the energy of light into electric energy. This is why I want to thank electromagnetic waves, which help people in their search for alternative sources of energy. I am using solar batteries for different purpose at home: to heat water in my pool, to operate the air conditioner, and even to illuminate my garden." 
•	W. D. # 2, Ms. Nghuen: "I have been working as a professional photographer for ten years now. Every day I marvel at how light can make the film in my camera produce beautiful images of objects. But now I am even more fascinated by the properties of invisible infrared waves. Isn't it wonderful that heat waves allow you to produce pictures of different objects. Using special cameras, you can form images that are otherwise invisible. We must be grateful to Mr. Hershel for his ability to investigate the unknown. Now we can use IR not only for military purposes, but also in astronomy. For example, we can get information about large low-temperature astronomical objects such as Betelgeuse in the Orion constellation; this star is considered to be a powerful source of IR waves. I can tell you that I am more than happy to use infrared photography in my work." 
•	W. D. # 3: " I am an avid reader. Most of all I like to read technical magazines and scientific articles. The most intriguing thing for me is that many modern inventions and discoveries are based on electromagnetic waves and their properties. Only recently I found many examples of this phenomenon, such as electromagnetic pumps, electromagnetic space engines, electromagnetic medicine, and electromagnetic universe. To tell you the truth, I don't understand how you can accuse waves that play such an important role in our lives. Don't you realize that we still inhabit this planet only because of electromagnetic radiation? 
•	W. D. # 4, Ms. Dawkins: "I am a scientist at the astrophysics laboratory at Berkeley. I am so angry! I definitely have to say something here. I need to defend UV! Our lab is well known to the whole world because of the respectful UV radiation. Right now we are participating in a NASA mission. The main goal of this mission is to analyze extreme UV radiation using a special satellite. Information received as a result of a full-sky survey (lasting 6 months) and a deep survey (along the sun ecliptic) will be studied very carefully, and many discoveries (about white dwarfs, for example) will probably be maid in the future. What I wanted to emphasize is that instead of accusing UV and other types of radiation, we should thank them for what they do for us. Ultraviolet and other waves are ubiquitous, and they are a vital tool in our scientific quest". 
•	W. D. # 5: "My name is Ann. I want to add something. I am a housewife and I have never worked anywhere outside my house. I have four kids and I don't know what I would do without this wonderful family of waves! To tell you the truth, I am using all of them. My kids and I are watching educational programs on TV and listen to the music on the radio. It means that we are using different radio waves - long and short. Sometimes when my kids are sick or hurt, doctors recommend using X-rays to make the right diagnosis, and infrared waves for physical therapy. UV waves help my children to be healthy because small exposure to this radiation stimulates the production of vitamin D in their bodies. It is so wonderful to have the whole family of electromagnetic friends at home." 
•	W. D. # 6, Mr. Manual Garcia: "Good afternoon. I want to apologize for taking your time, but I would like to complement one more type of radiation that is considered to be a very dangerous one. I am responsible for the maintenance of the Gamma Ray observatory, and can assure you that celestial gamma rays allow us to do miracles - to observe the death of a star, to understand the nature of mysterious quasars, pulsars, and even black holes! I urge you to reconsider your negative opinion about electromagnetic waves. 
•	C. J.: I think we should give the floor to the Chief Prosecutor. 
•	C. P.:  Honorable jurors, ladies and gentlemen. We have gathered today in this hall to consider the crimes committed by the electromagnetic gang. We have heard the testimony of only few witnesses for the prosecution, but we already know that all types of waves produce a lot of damage. But the most dangerous thing is the effect on the health of our people, and children in particular. How long shall we continue to be tolerant and patient. It is our duty to prevent this electromagnetic curse from spreading. We should say a resounding "no" to this phenomenon. 
•	C. J.: The floor is now given to the Counselor for the Defense. 
•	C. D.: The most honorable Chief Judge, members of the Jury. When the electromagnetic spectrum is considered from the legal point of view, it becomes obvious that the phenomenon has more merits then shortcomings. I don't want to repeat what the defense witnesses have told the Jury and the audience when they tried to demonstrate the benefits of electromagnetism. More than that, I want to question the validity of the testimony given by some of the prosecution witnesses. First of all, I want to point out that some of their conclusions about the relation between electromagnetic waves and cancer are still hypotheses, and they are not yet proven. Besides, we can always take measures to prevent their harmful effects. The most important thing is that we need electromagnetic waves, and we need all of them! They are our "brothers and sisters", and we should treat and use them with real respect. I hope that this wonderful family-spectrum will be proven innocent, and quite soon! More than that, our objective today is also to reward Electromagnetic waves for being so helpful to us in our everyday lives. 
•	C. J.: Having heard both sides, and upon conducting proper deliberations, the Jury delivers the following verdict: "After taking into account all useful manifestations of Electromagnetic Waves, on the one hand, and some negligibly negative side effects, on the other hand, the Jury has decided: (1) To further employ useful electromagnetic properties by creating new household and industrial devices; (2) To continue work directed at reducing damaging side effects of some electromagnetic waves; (3) To investigate the validity of the statements that some waves cause different types of cancer; (4) To continue using electromagnetic information in trial astrophysics in order to obtain the truthful picture of the Universe for the benefit of the humankind." 
•	S.: This session is thereby concluded.
At the end of the lesson the teacher explains his/her attitude toward the whole process of the "Trial" and points out the most interesting details. The merits and demerits of the lesson can be discussed during the next period. 
Copyright  1995, The Regents of the University of California. Retrieved from http://cse.ssl.berkeley.edu/lessons/indiv/nellie/new_nelli_trial. 
Electromagnetic Wave Presentation Rubric
5	4	3	2	1
	Organization and Cooperation
5   4   3   2   1 	Consistently work together as a well coordinated team (works well with others) 
5   4   3   2   1	Coordinate with team members; Assumes clear role & related responsibilities; Motivates others to do their best
5   4   3   2   1	Workload is divided and shared equally by all team members
5   4   3   2   1	Team members complete their share of the assigned task
5   4   3   2   1	Use problem solving skills with little re-direction from teacher
5   4   3   2   1	Stay on task and actively participate in project
5   4   3   2   1	Make effective use of class time, prepared and equipped
5   4   3   2   1	Students use correct punctuation, complete sentences, grammar and spelling (GUMS)
5   4   3   2   1	Gather abundance of material which clearly relates to the topic
5   4   3   2   1	Use a variety of resources
5   4   3   2   1	Create a bibliography with properly cited sources
5   4   3   2   1	Information clearly stated, well developed, and relevant
5   4   3   2   1	Information logical and flows together well
5   4   3   2   1	Specific examples are used to explain concepts
5   4   3   2   1	Students show complete understanding of presented material (answers class questions with explanation and elaboration)
5   4   3   2   1	Explains the characteristics of the electromagnetic wave including wavelength, frequency, and interesting facts
5   4   3   2   1	Explains where the electromagnetic wave is located on the spectrum and how it relates to other electromagnetic waves
5   4   3   2   1 	Explains the properties which place the electromagnetic wave in its position on the spectrum
5   4   3   2   1	Explains how the electromagnetic wave is related to everyday life or industry with at least 2 examples
5   4   3   2   1   	Use multimedia materials in presentation
5   4   3   2   1	Graphics explain and reinforce content of presentation
5   4   3   2   1	Original presentation of material that is fluent from beginning to end, logical sequence which audience follows
5   4   3   2   1	Make points in a creative way, creativity used in the presentation, shows original thought
5   4   3   2   1	Captures audience attention
5   4   3   2   1	Involves audience in presentation
5   4   3   2   1	Use poised, clear articulation during presentation
5   4   3   2   1	Make use of allotted time for presentation without going over
5   4   3   2   1	Communicates ideas with enthusiasm, proper voice projection, appropriate language, and clear delivery
5   4   3   2   1	Student maintains eye contact with audience, seldom returning to notes.
5   4   3   2   1	Student uses a clear voice and correct, precise pronunciation of terms so that all audience members can hear presentation.

NAME ____________________________________________________________________ DATE _____________________ CLASS ___________
Complete the following chart as you observe presentations:
(Wavelength, Energy,
Frequency)	EXAMPLES of
where its found
or used	Medical Concerns	QUESTIONS I HAVE









Use your data table above from class presentations and the following web site to complete the graphic organizer.



Name ___________________________________________ Date _________________ Class ____________

Debate on Federal Regulation of Electromagnetic Waves

Debate: Should the federal government be allowed to control the frequency bandwidths for communication?
Directions: The class will be divided into two groups. One group will be for federal regulation of electromagnetic waves, the other will be against. Research the important facts using the background information and web site taking notes to help during the debate. You will use these facts to support your opinion during the debate. The class will vote after the debate: Is it better for the federal government or private industry to decide on the use of frequency ranges of the electromagnetic spectrum? 
Background: (Used from http://school.discovery.com/lessonplans/activities/electromagneticspectrum/)
In the United States, radio and television stations emit two types of frequencies. In order for people to hear broadcasts, radio and television stations need to transmit along an audio frequency (AF) within the range of human hearing, which is 20 to 20,000 Hz. This audio frequency is transmitted along with a radio frequency that has been designated by the government. Radio frequencies distinguish each station. Some of the radio ranges designated by the Federal Communication Committee are:
AM radio: 530 — 1600 kHz
FM radio: 88-108 MHz
TV: 54-88 MHz (channels 2-6)
TV: 174-216 MHz (channels 7-13)
TV: ultra-high frequency (UHF), 470-890 MHz
Cellular telephones: 824 — 894 MHz.
The FCC also assigns ranges within radio and TV waves for use by airplanes, ships, police, military, cellular phone and amateur ham radio users. The federal government restricts usage of specific bandwidths within radio frequency for military use only.

Use the following web sites to collect information for the debate.
US Frequency Allocation Chart - Information on frequency ranges currently in use.
Federal Communication Committee – chart
International Regulations – Radio Communications Company, Air Waves

Follow up questions:
•	What are international regulations of air waves?
•	What are international implications of federal regulations of air waves?
•	What happens at the border of two countries differing on regulation of air waves; even though radio, television, and cellular stations may overlap?

•	Compare and contrast electromagnetic waves with other kinds of waves.
•	If radio waves are not compressional waves, like sound waves, explain what their role is in enabling us to hear music on our favorite radio station.
•	Thermograms are infrared photographs that show emission of infrared radiation emitted from objects. If you lived in a cold climate, how would a thermogram taken of your home be helpful to you as a homeowner?
•	Discuss why visible light is arranged into colors in the following order: red, orange, yellow, green, blue, indigo and violet.
•	Debate what we could do to prevent exposure to ultraviolet radiation if the ozone layer continues to deteriorate.
•	Defend the importance of gamma rays in treating cancer, even though many patients suffer serious side effects to such treatment.
•	What type of electromagnetic radiation does a flame emit?