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Stage 1
Identify Desired Results


Catchy Title: Sweet or Unsweet?
Theme/Topic of Lesson: The Artificial Sweetener Controversy
Time Commitment: Four 60-minute periods/blocks
Subject Area(s):
    Science
Grade Level(s): 6,7,8
Standards Alignment:
Class Challenge Question: How can we evaluate the credibility and objectivity of Internet and other sources on the safety of artificial sweeteners?
Overview:

Internet Research: Boon or Bane?
The artificial sweetener debate is an excellent case study of how scientific research is filtered and reported through the news media and the Internet.  Should you believe everything you read?  Are saccharin and aspartame really safe? With all the material that's out there, it's hard to tell.  Being able to assess the credibility, scope, and objectivity of any source is a vital scientific skill. As the Internet age swamps us with more information than we can handle, learning to think critically about Internet sources is an important life skill.  Comparing selected Internet publications on artificial sweeteners gives students an opportunity to develop their own criteria for credible, thorough, and objective source material.  This lesson challenges students to make their own judgments about the safety of artificial sweeteners after hands-on study and Internet research, and to support those judgments with carefully considered evidence and reasoning.

Artificial Sweeteners: Background
With the enormous emphasis Americans place on weight and weight loss, it should come as no surprise that the artificial sweetener market has flourished.  Millions of Americans use artificial sweeteners daily, because doing so gives them a way to have their cake and eat it too - to get the sweet taste without the caloric consequences.  Artificial sweeteners have also had great benefits for diabetics, allowing them to control their sugar intake while enjoying sweet-tasting food. 

Over the past 20 years, the scientific community has expressed sharply divided opinions about the safety of artificial sweeteners.  Though the most heated part of this debate occurred between 1983 and 1997, there is still plenty of discussion out there. 

The two main artificial sweeteners on the market are saccharin and aspartame.  Saccharin, 300 times sweeter than sugar, is actually quite old - it has been in use since 1879 - though concerns about its possible carcinogenic effects didn't arise until the mid-1970's.  Several different studies conducted between 1972 and 1977 demonstrated to the FDA's satisfaction that saccharin, when ingested in truly vast quantities, could cause bladder cancer in laboratory rats. As a result, saccharin has since carried a warning label which states that it "has been known to cause cancer in laboratory animals."

Aspartame, 180 times sweeter than sugar, was first introduced to the American public in 1981. Aspartame's debut coincided fairly closely with the explosion of the Internet.  As it happened, the fluid, easy medium of electronic publication served as the perfect conduit for both solid information and misinformation about the sweetener. 

Several early, Internet-propagated hoaxes about aspartame's risks have clouded what scientific evidence there is about the sweetener's safety.  A 1996 study attempting to link a 1983 rise in brain cancer rates with the introduction of aspartame in 1981 caused a great deal of concern among Americans, though the link was later shown to be false.  (For 3 reasons: (1) The rise in brain cancer rates had been ongoing for many years prior to 1983; (2) Any carcinogen takes many years to show its effects; and (3) Later studies showed that brain cancer rates have decreased since 1983, though consumption of aspartame has not.) Despite research to the contrary and statements by the FDA, the American Cancer Society, the National Cancer Institute (a division of the National Institutes of Health), and other reputable sources, Internet sources claiming to link aspartame to everything from fatigue and dizziness to epilepsy still abound.   

During the course of this lesson, your students will assume the role of the manager of a new restaurant.  The owner of the restaurant is trying to decide which, if any, artificial sweeteners the restaurant should use in its menu or offer on its tables.  The owner of the restaurant is very health-conscious, and doesn't want to offer any sweetener that poses a health risk to diners.  On the other hand, the owner would also like to cut back the amount of sugar used on the menu in order to entice diners wanting lower-calorie fare.  The student/manager's role is to research the issue and make a recommendation.

Students will spend the first 50-minute lesson conducting experiments to observe some of the physical and chemical properties of natural and artificial sugars.  In the second lesson, students will construct a timeline of the artificial sweetener debate, including significant studies that marked "turning points" in the debate.  In the third lesson, students will use real data to see if there is a correlation between artificial sweeteners and cancer incidents.  They will then use their own reasoning skills and research to determine if the relationship they see is causal or not - in other words, if artificial sweeteners, in their opinion, are safe or unsafe for public consumption.  In the culminating task, students will use everything they have learned to write a recommendation to the restaurant owner.  The recommendation will include which sweeteners (if any) are to be used in dessert items and/or offered on the tables.  The recommendation should be supported by accompanying evidence and thorough reasoning. 

Prerequisite skills for the teacher include how to use a computer with Internet access and a projection device and a working knowledge of basic laboratory safety.  Prerequisite skills students need in order to successfully complete this lesson include the ability to graph, employ lab safety, create a timeline, and to make critical judgments about scientific studies (i.e., their objectivity and thoroughness, possible sources of error, etc.). Students should also have some background knowledge of what environmental health risks are and the role they are thought to play in diseases such as cancer. 



Stage 2
Determine Acceptable Evidence


Skills and Processes
(K-12)
Maryland Content Standards Indicators
Students will explain how the nature of science has affected scientific inquiry, technology, and the history of science.
 
Skills and Processes
(6-8)
Maryland Content Standards
Students will explain how the nature of science has affected scientific inquiry, technology, and the history of science.
Maryland State Indicators
1.8.1
access and process information from readings, investigations, and /or oral communications. (MLO 1.1.1.)
Skills and Processes
(6-8)
Maryland Content Standards
Students will explain how the nature of science has affected scientific inquiry, technology, and the history of science.
Maryland State Indicators
1.8.4
recognize/develop well-designed procedures that identify the independent and dependent variables, the need for control when testing a factor, the importance of multiple trials, the selection of appropriate materials/equipment, and the development of clear, logical directions within an investigation. (MLO 1.1.4.)
Skills and Processes
(6-8)
Maryland Content Standards
Students will explain how the nature of science has affected scientific inquiry, technology, and the history of science.
Maryland State Indicators
1.8.5
demonstrate safety when conducting an investigation.
Skills and Processes
(6-8)
Maryland Content Standards
Students will explain how the nature of science has affected scientific inquiry, technology, and the history of science.
Maryland State Indicators
1.8.8
analyze and summarize data to identify trends and form a logical argument about a cause and effect relationship or a sequence of events. (MLO 1.1.7.)
Chemistry
(K-12)
Maryland Content Standards Indicators
Students will use scientific skills and processes to explain the composition, structure, and interactions of matter in order to support the predictability of structure and energy transformations.
 
Chemistry
(6-8)
Maryland Content Standards
Students will use scientific skills and processes to explain the composition, structure, and interactions of matter in order to support the predictability of structure and energy transformations.
Maryland State Indicators
4.8.1
distinguish one substance from another based on observable and measurable properties (i.e., density, boiling point, melting point). (MLO 4.1.)
Writing
(K-12)
Maryland Content Standards Indicators
Students produce informational, practical, persuasive, and narrative writing that demonstrates an awareness of audience, purpose and form using stages of the writing process as needed (i.e., pre-writing, drafting, revising, editing and publishing).
 
Writing
(6-8)
Maryland Content Standards
Students produce informational, practical, persuasive, and narrative writing that demonstrates an awareness of audience, purpose and form using stages of the writing process as needed (i.e., pre-writing, drafting, revising, editing and publishing).
Maryland State Indicators
3.8.6.2
write reports for an intended audience and purpose that
  • convey a clear and accurate perspective on the subject
  • support the main ideas with facts, details, examples, and explanations (MLO.W. 1.7.)
  • pose relevant and tightly drawn questions about the topic
  • Technology research tools
    (Gr. 6-8)
    ISTE Technology Standards

    5. Technology research tools

    • Students use technology to locate, evaluate, and collect information from a variety of sources.
    • Students use technology tools to process data and report results.
    • Students evaluate and select new information resources and technological innovations based on the appropriateness for specific tasks.
    ISTE Technology Performance Indicators
    Research and evaluate

    Research and evaluate the accuracy, relevance, appropriateness, comprehensiveness, and bias of electronic information sources concerning real-world problems.

    Social, ethical, and human issues
    (Gr. 6-8)
    ISTE Technology Standards

    2. Social, ethical, and human issues

    • Students understand the ethical, cultural, and societal issues related to technology.
    • Students practice responsible use of technology systems, information, and software.
    • Students develop positive attitudes toward technology uses that support lifelong learning, collaboration, personal pursuits, and productivity.
    ISTE Technology Performance Indicators
    Research and evaluate

    Research and evaluate the accuracy, relevance, appropriateness, comprehensiveness, and bias of electronic information sources concerning real-world problems.

    Technology problem-solving and decision-making tools
    (Gr. 6-8)
    ISTE Technology Standards

    6. Technology problem-solving and decision-making tools

    • Students use technology resources for solving problems and making informed decisions.
    • Students employ technology in the development of strategies for solving problems in the real world.
    ISTE Technology Performance Indicators
    Research and evaluate

    Research and evaluate the accuracy, relevance, appropriateness, comprehensiveness, and bias of electronic information sources concerning real-world problems.



    Learning Objectives:

    The Students will:
    • Observe and record the physical and chemical properties of sugar, saccharin, and
      aspartame.
    • Compare the properties of sugar, saccharin, and aspartame.
    • Gather information on the history of artificial sweeteners.
    • Research a position in the artificial sweetener debate.
    • Evaluate the accuracy, comprehensiveness, and bias of research on artificial
      sweeteners.
    • Synthesize information learned in order to write a memo to a restaurant owner
      recommending the use or non-use of aspartame and/or saccharin in a new restaurant.

    Assessment
    The content and technology integration of this lesson will be assessed with the Sweetener
    Project Assessment.


    Stage 3
    Plan Learning Experiences


    Resources

    SoftwareInternet Browsers - Microsoft Internet Explorer
      http://www.microsoft.com
    Word Processor - Microsoft Word
      http://www.microsoft.com
    Pre-Writing Organizer - Inspiration
      http://www.inspiration.com
    Internet SitesSUNY Albany Library: Evaluating Internet Resources An excellent and thorough bulleted list of points to consider when evaluating the validity, scope, objectivity, and credibility of Internet resources.
      http://library.albany.edu/internet/evaluate.html
    Brain Pop An online science video site. Select the movie called Cancer for the second activity.
      http://www.brainpop.com/health/diseases/cancer/index.weml
    ChemFinder.com Enter chemical name (i.e., aspartame, saccharin) into the search engine to access chemical model and information.
      http://chemfinder.com
    Sweeteners: Sides of the Aspartame Debate NCI's official statement as to the risks and possible carcinogenic effects of aspartame and saccharin.
      http://cis.nci.nih.gov/fact/3_19.htm
    American Cancer Society: Aspartame Facts & Statement
      http://www.cancer.org/eprise/main/docroot/PED/content/PED_1_3X_Aspartame?sitearea
    FDA on Artificial Sweeteners FDA informational statement on artificial sweeteners that includes a great deal of
    information on the history of both saccharin and aspartame.
      http://www.fda.gov/fdac/features/1999/699_sugar.html
    Aspartame.info A site maintained by the aspartame industry that includes a thorough FAQ section on the health risks of aspartame, summaries of medical & scientific studies on aspartame, and a link to information on Internet rumors about aspartame.
      http://american.aspartame-info.com/media/default.asp
    Aspartame is NOT Safe A site maintained by an individual diagnosed with prostate cancer.  A comprehensive list of links to other anti-aspartame sites.
    http://www.dorway.com/betty/allolney.txt
      http://www.dorway.com/

    Materials
    Per class
    • computer with internet access
    • video projection device
    Per student team/group of 2
    • Computer with a Internet access and Web browser program, a word
      processing program, and a pre-writing organizer program such as Inspiration
      installed
    • meter stick
    • metric ruler
    • 2 meters of white cash register tape
    • scissors
    • 3 100 mL beakers
    • examples of sugar, aspartame, and saccharine
    • 3 microscope slides
    • 3 cover slips
    • scoopula
    Per Student
    • Comparing Natural and Artificial Sweeteners  (View)
    • The Great Sweetener Debate Timeline  (View)
    • Carcinogen Video Questions  (View)
    • Evaluating Sweetener Sources  (View)
    • Getting Your Thoughts Together  (View)
    • How Do We Judge Internet Sites  (View)
    • Sweetener Restaurant Memo  (View)
    Not Specified
    • Great Sweetener Debate Timeline Answer Key  (View)
    • Sweetener Project Assessment  (View)

    Vocabulary
    • Aspartame - artificial sweetener used in many diet products. Introduced in the U.S. in 1981. Chemical composition is C14H18N2O5
    • Carcinogen - a substance that can increase one's risk of cancer with prolonged exposure
    • Saccharine - artificial sweetener used in many diet products. In use since 1897. Chemical composition is C7H5NO3S
    • Volatility - ability of a substance to turn into a gas
    • Solubility - ability of a substance to dissolve in liquid

    Procedures

    This lesson includes many different instructional strategies. Students complete a hands-
    on science investigation with a partner. Students participate in both partner and group
    Internet investigations that include information gathering and data collection. Individuals
    are responsible for graphing results and completing the cumulative writing activity. Each
    day begins with the teacher modeling and concludes with an informal assessment of the
    days’ activities. Technology is integrated throughout the lesson. The class watches a
    streaming Internet video and students use the Internet to collect information and data.

    All activities are structured to accommodate different learning styles and abilities.
    Modifications can be implemented throughout these lessons to provide for the success of
    all students. Heterogeneous groups are a good way to provide support for lower
    performing students. Also, the use of graphic organizers and allowing extended time will
    assist those students with disabilities. Students can be paired during the writing process
    so that they can receive feedback from their peers on their writing. Extension activities
    can be used to enrich the lesson for high achieving students.

    In order to complete the first day of the lesson, a chemistry lab with access to an eye
    wash (in case of eye contamination with the sweeteners), microscopes, and other
    materials (see Materials section) is needed. 

    In order to complete the second and third days of the lesson, a classroom computer with
    Internet access and a projection device is also needed. For days two and three, it would
    also be ideal to be in a computer lab with enough computers for every pair of students. If
    the computer lab cannot be arranged, the students can rotate through any computers
    available in the classroom. Another situation may require the teacher to print out certain
    documents from the Internet and copy them for students. Students can also complete both
    the graphing and writing activities on paper instead of on the computer.


    Day 1: Comparing Natural and Artificial Sweeteners
    Daily Challenge Question: What are the observable physical and chemical differences between sugar, saccharin, and aspartame?
    1 Day
    Set-up Directions:

    Prior to day one the teacher needs to prepare all materials for the Comparing Natural and Artificial Sweeteners Activity.  Supplies should be grouped and assembled for easy distribution. The teacher should make a list of assigned lab groups of 4 students each. Each group will need a kit containing 3 100 mL beakers, samples of sugar, aspartame, and saccharine, 3 slides, 3 cover slips, and a scoopula. Ideally, each kit would be set up next to a microscope.  If this is not possible, set up microscope stations so that students may rotate through as they complete the activity. 

    Also keep safety in mind during the room setup - make sure to allow adequate walking and moving space between stations, as well as adequate walking space behind stations.  Lab safety information should be posted in the room, and there should be a first aid kit that is well stocked and easy to retrieve.



    Teacher Presentation & Motivation:

    Warm-Up

    Ask students to help you list and describe some artificial and natural sweeteners.  Make a list of student responses on the board, chart paper, or overhead transparency.  Then briefly describe each kind of sweetener (i.e., aspartame is 180 times sweeter than sugar, saccharin is 300 times sweeter, etc.)  Where possible, help the class identify brand-name sweeteners as saccharin, aspartame, or sugar.  You may wish to discuss the fact that sugar itself comes in many different forms: granulated, powdered, brown, white, "raw," etc. 

    Once you have identified artificial sweeteners as saccharin or aspartame, ask students if they have heard anything about any positive or negative effects these sweeteners have on the body from sources such as books, television, the Internet, family, or friends.  Gather several student responses before proceeding.  Then tell students,

    Over the next few days, we are going to study artificial sweeteners.  I want you to imagine that you've just been hired as the manager of a new restaurant.
    "I want my foods to be both safe and healthy," your boss tells you, "but I don't know what to do about artificial sweeteners.  Should we put saccharin, or aspartame, or both on the tables as an alternative to sugar?  I don't want to put the health of our diners at risk.  On the other hand, I know our diners will be diet-conscious and want to see low-calorie items on the menu.  Artificial sweeteners can give them the sweet taste without the calories.  I need you to research the issue and give me your recommendation as to what artificial sweeteners, if any, should go on our tables and in our menu, and why."

    Then, explain to students:

    There has been a lot of debate about the safety of saccharin and aspartame.  There are respected scientists on both sides of the debate - those who believe saccharin and aspartame pose certain health risks, and those who believe that they do not.  You will take a close look at the physical and chemical properties of aspartame, sugar, and saccharin today. Over the next two days, you will work individually and in groups to research the issue and prepare your report for your boss.



    Activity 1 - Comparing Natural and Artificial Sweeteners

    Pass out the "Comparing Natural and Artificial Sweeteners" sheet and direct lab groups to their stations.

    Part 1: Observing the Physical Appearance.
    In this activity, students will compare the appearance of sugar, aspartame, and saccharin under the microscope and draw a sketch of each sweetener's appearance. When students have completed their observation, proceed to Part II.

    Part 2: Volatility
    In this activity, students will compare the volatility of sugar, aspartame, and saccharin.
    Explain:
    Volatility is a chemical's ability to turn into a gas. A chemical has a high volatility if it evaporates easily under normal temperatures and pressures. Highly volatile chemicals emit a strong odor. Can you guess why?
    (Student responses will vary.  A reasonable explanation is that you can smell the chemical when it is in gaseous form, so the most volatile substances smell the strongest.  If you like, explain that all smells are particulate.)
    Have students smell each sample and write high, medium, or low on Part II of their "Sweetener Investigation" sheet.

    Part 3: Solubility
    In this activity, students will compare the solubility of each sweetener. Explain:
    Solubility is a chemical's ability to dissolve in liquid. A chemical is highly soluble, for example, if it dissolves easily in water.  Do you think solubility would be an important property in a sweetener?  Why?
    (Student responses will vary. A reasonable answer is that since sweeteners are used most often in liquids like iced tea and lemonade, you would want a sweetener to be highly soluble.  Both saccharin and aspartame are soluble at lower temperatures than sugar.)

    Part 4: Analysis
    In this activity, students will use their observations to write a paragraph describing at least 2 similarities and 2 differences between the samples for each of the physical and chemical properties observed.



    Wrap Up:
    Ask students to clean their slides, scoopulas, and beakers, and arrange them neatly in their work area.  Ask them to make sure the work area is clean and dry.  Collect the Comparing Natural and Artificial Sweeteners sheets from each student.  Explain that we will be looking at the history of artificial sweeteners and the debate about their safety tomorrow. 

    Day 2: History of the Artificial Sweetener
    Daily Challenge Question: What does the timeline of the debate on artificial sweeteners look like, and what were its key turning points?
    1 Day
    Set-up Directions:
    Prior to day one the teacher needs to prepare all materials for the Carcinogen Video Activity and The Great Sweetener Debate Activity.  To complete Activity 1, there should at least be an Internet-ready computer with a viewing projection device in the classroom.  For Activity 2, students can work at their computer stations in small groups or, if this is not possible, they can work from copied printouts of the FDA Web site (http://www.fda.gov/fdac/features/1999/699_sugar.html). (If you choose to print the Web page, you may omit the last section entitled "Other Sweetener Choices.") 


    Teacher Presentation & Motivation:

    Warm-Up
    Ask students if they know the names of some carcinogens.  Record responses on the board, chart paper, or an overhead transparency.  Once you have a list, ask students if they can describe what a carcinogen does. 
    (The most common response is that a carcinogen causes cancer, which is acceptable. Be sure to clarify as follows, however.)
    Explain that we don't really know why any one person gets cancer, but we do know that there are some things that can increase a person's risk of getting cancer.  We call these things carcinogens.  Some carcinogens, like smoking and unprotected exposure to sunlight, are more dangerous than others. 

    When doctors think a substance might be a carcinogen, they study it until they determine 2 things: (1) if it is a carcinogen, and (2) if it is, how much it increases people's risk of getting cancer. 

    Point out that when someone gets cancer, it is almost impossible to say with certainty that the cancer was caused by one carcinogen or another.  We study carcinogens so we can help people avoid increasing their risk of getting cancer, but sometimes people get cancer for no reason we can find.



    Activity 1 - Carcinogen Video
    In this activity, students will learn what carcinogens are and how they can influence a person's risk of developing cancer.
    Focus for Media Interaction
    Focus for Media Interaction: The focus for media interaction is a specific task to complete and/or information to identify during or after viewing of video segments, Web sites or other multimedia elements.
    The focus for media interaction is a specific task to complete and/or information to identify during or after viewing of video segments, Web sites or other multimedia elements. The focus for media interaction for the cancer video is for students to learn what a carcinogen is and how it can influence a person's risk of developing cancer.
    Viewing Activities
    What will your students be responsible for while viewing this piece of multi-media or video?
    Go to http://www.brainpop.com and select "cancer" from the video drop-down menu at the top. Play the cancer video clip until Tim says "People get cancer when their cells reproduce too quickly." Click on Pause. Say to the students:  I'm going to play that section again, and I want you to record on your Carcinogen Video half-sheet what happens to a person's cells when they get cancer.  Click on the Rewind button and then on the Play button.  Pause again at the same place and allow students to share what they recorded about cancerous cells.  Play more of the video until Tim says, "These tumors can interfere with your body's natural functions and cause health problems."  Tell students: I'm going to play that again, and I want you to record what a carcinogen can do to a person's cells.  Click on the Rewind button and then on the Play button.  Pause again at the same place and allow students to share what they recorded.

    Post Viewing Activities
    How will students utilize the information they gathered while viewing the multi-media or video?
    The parts of the cancer video should prepare students to discuss the heart of the debate about artificial sweeteners: whether or not they are carcinogens.  After viewing the parts of the cancer video, students will complete a timeline activity with a partner.  Explain that much of the debate about artificial sweeteners has centered on the question of whether or not they are carcinogens - whether or not they cause cancer. Explain that they will now be looking more closely at the history of artificial sweeteners and the public dialogue about them.

    Activity 2 - The Great Sweetener Debate

    In this activity, students will learn some of the history of artificial sweeteners and the major turning points of the artificial sweetener debate.  Direct students to the FDA's website on artificial sweeteners (http://www.fda.gov/fdac/features/1999/699_sugar.html) or hand out copies of the web page to each group. 

    Part 1
    Have students complete the Great Sweetener Debate sheet using the information found on the FDA Web site.

    Part 2
    Have students work in groups of 3 or 4 to create a timeline of the artificial sweetener debate, using the information from their handouts as a guide.  Remind students that all timelines have a scale that equates intervals of time to intervals of distance.  The scale for this timeline is 1 meter = 100 years.  As you circulate, help students remember all the components of a timeline: a title, equidistant lines, a scale, events, and a line with arrows at the ends.



    Wrap Up:
    Ask students to finish up their timelines and return the materials to their proper places. Collect the Carcinogen Video half-sheets, The Great Sweetener Debate sheet, and the students' timelines.
    Explain that we will look more closely at some of the scientists' and doctors' arguments about artificial sweeteners tomorrow.

    Day 3: Reliable Resources
    Daily Challenge Question: How do we decide which resources on the safety of artificial sweeteners are reliable and credible?
    1 Day
    Set-up Directions:
    Prior to Day 3, the teacher needs to prepare all materials for the 2 activities.  Each group of students (preferably 2-3) should have access to a computer station with Internet access.  Make 1 copy of the How Do We Judge? half-sheet and the Evaluating Sweetener Sources activity page for each student.  Prepare a computer with Internet access and a video projection device for the warm-up.  The teacher also needs to visit the "Evaluating Internet Sources" Web site listed in Activity 1, and familiarize him/herself with the terminology in this tutorial.

    Teacher Presentation & Motivation:
    Ask students:  If you wanted to find out today's world news, where on the Internet could you look?
    (Responses may include sites such as www.cnn.com, www.nytimes.com, www.washingtonpost.com, www.msnbc.com, etc.)

    Choose from responses and go to a news web site on the video projection-linked computer. 

    Ask: Do all news web sites report the news the same way?
    (Responses will vary.)  Point out that, for instance, news of an attack on one country by another would be reported very differently by different sources. 

    Ask: What might the story look like from the side of the country that was attacked? What might the same story look like from the other country's side? Why are they different?

    Explain that all sources of information, even ones that are widely acclaimed, need to be looked at carefully and compared with other sources.  When we do this, we can look at 5 different aspects of each source to decide how to weigh its contents.  These aspects are the Web site's accuracy, authority, objectivity, currency, and coverage.  Let's look at what these mean.  (Hand out the How Do We Judge? half-sheets.)


    Activity 1 - How Do We Judge?
    At their computer stations, have students go to the "Evaluating Internet Sources" tutorial at http://www.lib.purdue.edu/InternetEval/nondhtmlintro/nondhtmlintro.html.  Have them use the links on this site to write definitions for each of the five criteria for evaluating Internet sources (accuracy, authority, objectivity, currency, and coverage) on their How Do We Judge? half-sheets.  Ask students to put the definitions in their own words as much as possible.

    Activity 2 - Evaluating Sweetener Sources
    Have students complete the Evaluating Sweetener Sources worksheet by going to each of the Web sites and rating its accuracy, authority, objectivity, currency, and coverage on the chart provided.  Circulate among groups and make sure students understand the definitions of the 5 criteria.  If needed, explain to students that the questions provided on the left side of the chart are "for thinking" only; they don't need to answer them in the chart.    

    Wrap Up:
    Have 2 or 3 students share their answers to the analysis questions with the class.  Explain that everyone's chart and responses will be different, and that's okay.   The important thing is that students have looked critically at the sites and considered how each one measures up to all 5 criteria.

    Explain that we will be putting everything we've learned together tomorrow.  We will be making our recommendations to the restaurant owner about whether or not he should use saccharin or aspartame in addition to sugar, and in what way each sweetener should be used.

    Day 4: Taking A Position
    Daily Challenge Question: What is my position on artificial sweeteners and what are my supporting reasons?
    1 Day
    Set-up Directions:
    Prior to Day 4, the teacher will need to 1 copy per student of each of the activity sheets.  Ideally, class would be held in a computer lab so that each student has access to a computer with the Inspiration pre-writing software installed.  If this is not possible, other pre-writing activities such as FAT-P (form, audience, topic, purpose) and Critical Thinking Squares may be used. 
      

    Teacher Presentation & Motivation:
    Warm-Up
    So, you've learned about the history of artificial sweeteners, reviewed what lots of people and organizations have to say about them, and you've looked at some of their physical and chemical properties for yourself.  Now, you need to give your boss a recommendation.  The restaurant owner will need to understand your position and your supporting reasons.  What are the possible positions?
    Responses will vary.  Point out that in addition to the 2 obvious positions (artificial sweeteners are safe/unsafe), there are other "compromise" positions, such as:
    -- The restaurant owner should use aspartame, but not saccharin.
    -- The restaurant owner should only offer the sweeteners on the table, but not in the foods on the menu.
    -- The restaurant owner should offer the sweeteners, but post a warning about the risks on each table.


    Activity 1 - Getting Your Thoughts Together
    Distribute the Getting Your Thoughts Together sheet to students at their computer
    stations.

    Activity 2 - Sweetener Memo
    Have students complete the Sweetener Memo writing activity at their computer stations.


    Wrap Up:
    Collect both the pre-writing activities and the Sweetener Memo activity from all students. 
    Explain that they have just done something that many professionals have to do from time
    to time: think about an issue, look at the evidence, and make a recommendation about a
    course of action.

    Enrichment Options
    Community Connection

    Students could keep the community aware of the sweetener debate by creating their own
    pro/con Web site about aspartame and saccharin.  The site could explain both sides of the
    issue (the evidence for and against sweetener safety) and offer links to other sites.

    Students could also use what they’ve learned to write a letter to the editor of their local
    newspaper stating their position on artificial sweeteners. 



    Cross-Curricular Extensions

    Mathematics
    Students could graph the cancer incidence rates by year using the information found at
    http://www.cancer.org/docroot/stt/stt_0.asp.  They could then determine if a
    correlation exists between the introduction of aspartame in 1981 and a change in cancer
    incidence rates.  Further, they could decide if this correlation shows a causal relationship
    (i.e., if a change in cancer incidence rates was caused by aspartame)

    Science
    Students can study the history and evidence provided in other carcinogen debates, such as
    that of tobacco.  More information can be found at http://www.cancer.org.
      
    Technology
    Students can create a PowerPoint presentation describing all that they have learned from
    this lesson.




    Stage 4
    Teacher Reflection


    As a reflective practitioner, note how this lesson could be adjusted after its initial
    implementation. How successful were the students? What did the assessment demonstrate
    about the students’ learning?  What skills do the students need to revisit?  What
    instructional strategies worked and what made them successful?  What will you change
    the next time you use this lesson?  Why? 

    Author: Kevin Feeney and Jennifer Petering
    Modified by: Stephanie Kadel