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    Testing for Vitamin C in Different Drinks and Foods
    For Science Labs, Lesson Plans, Class Activities & Science Fair Projects
    For Primary and Elementary School Students & Teachers


    This experiment is courtesy of 

    Testing for Vitamin C in different drinks and foods

    Developers:

    Brenda Ortiz
    Fairhill Elementary School
    School District of Philadelphia
    Philadelphia, PA

    Dottie Reed
    Walton Farm Elementary School
    North Penn School District
    Lansdale, PA

    Enrique Michelotti, Ph.D.
    Rohm and Haas Company
    Spring House, PA

    Paul Reibach, Ph.D.
    Rohm and Haas Company
    Spring House, PA

     

    Grade Level:

    2 through 6

     

    Disciplines:

    Physical Science (Chemistry), Health (Nutrition), Math, Language Arts, Social Studies

     

    Goals:

    Students will:

    1. develop an understanding of the importance of Vitamin C in their diet.

    2. learn sources of Vitamin C.

    3. develop an awareness of the use of Vitamin C in helping our environment.

    4. gain exposure to chemical procedures and techniques.

    5. analyze and interpret data by keeping a data sheet and making a bar graph.

    6. have many opportunities for hands-on science activities.

    7. keep a science notebook throughout the unit.

    8. learn that science can be fun!

     

    Background:

    These activities on Vitamin C testing can be used to strive towards the following Benchmarks for Science Literacy (see bibliography):

    By the end of second grade, students should know that:

    1B - People can often learn about things around them by just observing those things carefully, but sometimes they can learn more by doing something to the things and noting what happens.

    - Describing things as accurately as possible is important in science because it enables people to compare their observations with those of others.

    1C - In doing science, it is often helpful to work with a team and to share findings with others. All team members should reach their own individual conclusions, however, about what the findings mean.

    2C - Numbers and shapes can be used to tell about things.

    4C - Change is something that happens to many things.

    4D - Objects can be described in terms of the materials they are made of (clay, cloth, paper, etc.) and their physical properties (color, size, shape, weight, texture, flexibility, etc.)

    - Things can be done to materials to change some of their properties, but not all materials respond the same way to what is done to them.

    6D - People can learn from each other by telling and listening, showing and watching, and imitating what others do.

    6E - Eating a variety of healthful foods and getting enough exercise and rest help people to stay healthy.

    8E - Letters and numbers can be used to put things in a useful order.

    9A - Numbers can be used to count things, place them in order, or name them.

    - It is possible (and often useful) to estimate quantities without knowing them exactly.

    - Simple graphs can help to tell about observations.

    9B - Sometimes changing one thing causes changes in something else. In some situations, changing the same thing in the same way usually has the same result.

    9D - Some things are more likely to happen than others. Some events can be predicted well and some cannot. Sometimes people aren't sure what will happen because they don't know everything that might be having an effect.

    11C - Things can change in different ways, such as in size, weight, color, and movement. Some small changes can be detected by taking measurements.

    12A - Raise questions about the world around them and be willing to seek answers to some of them by making careful observations and trying things out.

    12D - Describe and compare things in terms of number, shape, texture, size, weight, color, and motion.

    - Draw pictures that correctly portray at least some features of the thing being described.

    12E - Ask "How do you know?" in appropriate situations and attempt reasonable answers when others ask them the same question.

    By the end of 5th grade, students should know that:

    1B - Scientific investigations may take many different forms, including observing what things are like or what is happening somewhere, collecting specimens for analysis, and doing experiments. Investigations can focus on physical, biological, and social questions.

    - Results of scientific investigations are seldom exactly the same, but if the differences are large, it is important to try to figure out why. One reason for following directions carefully and for keeping records of one's work is to provide information on what might have caused the differences.

    - Scientists do not pay much attention to claims about how something they know about works unless the claims are backed up with evidence that can be confirmed and with a logical argument.

    1C - Clear communication is an essential part of doing science. It enables scientists to inform others about their work, expose their ideas to criticism by other scientists, and stay informed about scientific discoveries around the world.

    - Doing science involves many different kinds of work and engages men and women of all ages and backgrounds.

    2A - Mathematical ideas can be represented concretely, graphically, and symbolically.

    6C - From food, people obtain energy and materials for body repair and growth. The indigestible parts of food are eliminated.

    6D - Humans can use the memory of their past experiences to make judgments about new situations.

    6E - Food provides energy and materials for growth and repair of body parts. Vitamins and minerals, present in small amounts in foods, are essential to keep everything working well. As people grow up, the amounts and kinds of food and exercise needed by the body may change.

    - Tobacco, alcohol, other drugs, and certain poisons in the environment can harm human beings and other living things.

    9B - Tables and graphs can show how values of one quantity are related to values of another.

    9D - Some predictions can be based on what is known about the past, assuming that conditions are pretty much the same now.

    12A - Keep records of their investigations and observations and not change the records later.

    12C - Measure and mix dry and liquid materials in prescribed amounts, exercising reasonable safety.

    - Keep a notebook that describes observations from ideas and speculations about what was observed, and is understandable weeks or months later.

    12D - Make sketches to aid in explaining procedures or ideas.

    - Use numerical data in describing and comparing objects and events.

     

    Introduction:

    Many students know that vitamins are important to their health. However, they may not know why. Because vitamins cannot be experienced through the senses, students may not know that foods they may commonly eat contain vitamins. They also may not understand the importance of vitamins in their diets.

    Ascorbic acid, commonly known as Vitamin C, is important to the human diet. It helps the body form connective tissue, bone, teeth, blood vessel walls, and assists the body in assimilating iron and amino acids. A diet deficient in Vitamin C may cause a person to develop scurvy. Symptoms of this disease, which include joint stiffness, nose bleeds, swollen and bleeding gums, livid spots on skin, and prostration (extreme physical weakness), can be prevented by adding Vitamin C to one's diet. Plants and some animals make their own Vitamin C, but humans do not. For this reason, humans need to seek Vitamin C from other sources.

    Vitamin C is also an anti-oxidant. This means that it will help prevent oxidation. Consider foods that contain little or no Vitamin C, such as apples and bananas. After exposure to the air, these fruits turn brown. Now consider foods that contain a large amount of Vitamin C, such as oranges, lemons, and limes. When these fruits are exposed to the air, they do not turn brown. This is due to Vitamin C's ability as an anti-oxidant. (Students will observe this phenomena in Activity #7.)

    Children and adults should gain knowledge as to why they need to choose foods rich in Vitamin C, not just the "junk food" they enjoy eating. They should also learn that there are things we cannot see contained in foods and other things around us. Most people are probably unaware that in the United States, 60 milligrams of Vitamin C is the recommended daily allowance. The following lessons and experiments can be used to introduce children to this knowledge in an exciting manner.

    In some of the experiments, a commonly used hands-on laboratory technique known as titration will be introduced to students. A titration involves adding one solution dropwise into another solution until a color change is observed. When a color change is noted, the titration process has reached the end point.

    In order to perform the titrations, an indicator solution is usually used. Two different indicators are described in this unit, but only one needs to be used. The two indicators are indophenol, and cornstarch-iodine solution. Both indophenol and iodine are dangerous substances. However, with much caution and supervision, any problems can be avoided.

    Indophenol is a blue powder, which is mixed with water to form a deep blue indicator solution. The color changes (blue to purple to pink to colorless, and various shades in between) that can be observed during a titration using indophenol are vivid and exciting. However, indophenol is a toxic substance, and the indophenol solution should be made by the teacher, not the students. Students should wear gloves and safety goggles when handling indophenol solutions. Disposal of the waste solutions containing indophenol may also be a problem. It should not be poured down a school drain. If you plan to use the indophenol solution, check with your school, area colleges, local chemical companies, or your local government for advice or information on collection possibilities before you begin these experiments. Indophenol must be purchased through a chemical supplier. Also, if you plan to use indophenol instead of the cornstarch-iodine solution, you may skip Activity #1, which is a starch test that will help introduce the alternate indicator solution.

    Iodine is also a toxic chemical, but has less potential dangers. It is a common household item, which is often used on skin to help heal cuts. Iodine and cornstarch are both easily available in supermarkets, and iodine can also be found in drugstores. Because iodine is used on the skin, gloves are not necessary, though they are helpful. The cornstarch-iodine solution can be made by the students themselves, allowing them to exert more power and independence in the experiment. The color change observed may not seem as exciting as that observed using indophenol, but it can still be quite intense. The cornstarch-iodine solution may be poured down the drain, though you may still want to check with your school before doing so.

    Cornstarch is a household food item, and does not pose any potential dangers in classroom use.

     

    Activity 1: Testing for Starch

    (Possible activity prior to testing for Vitamin C. Complete this activity if you plan to use the cornstarch-iodine solution for testing for Vitamin C.)

     

    Objectives:

    Students will:

    1. learn a chemical testing procedure for the presence of starch in a food.

    2. recognize by color which foods contain starch.

    3. participate in hands-on activities.

    4. learn that science can be fun.

     

    Background:

    Foods that contain starch will turn a blue-black when a drop or several drops of the indicator are added to the food. The more starch a food contains, the deeper the color will appear. The teacher can add other foods containing starch that students do not bring in, or students can investigate on their own on another day. Examples of foods containing starch include potatoes, rice, and cornstarch. Paper contains starch to make it stronger and smoother. Confectioner's sugar contains starch to prevent caking.

    Iodine is a poison and discussion with students at this time as to safety precautions is most important. Also, discuss the method of disposal for the food samples.

     

    Materials:

    bread
    crackers
    potatoes
    other foods or items that contain starch (see background)
    paper towels
    tincture of iodine
    samples of food to be tested, brought by the students
    pipets, eyedroppers, or straws (one for each student)

    (You may use a straw in place of a pipet by placing one end of the straw into the solution and your finger over the other end. To transfer the solution from the straw to a food, keep your finger on the straw until you are ready to release the solution.)

     

    Procedure:

    1. Children put samples of food to be tested on their paper towel.

    2. If this is their first time using a pipet, instruction will need to be given so students can get only one drop at a time on their food samples. (It might be helpful to practice with water if additional pipettes are available.)

    3. Students should allow a few drops of iodine to fall directly on the sample and observe the results.

    Students should record the results of each sample of food by writing and/or drawing in their notebook.

     

    Critical Thinking Questions:

    1.What samples contain starch?

    2.How can you tell which samples contain starch?

     

     

    Activity 2: Testing for Vitamin C in Juice

    Objectives:

    Students will:

    1. demonstrate the chemical procedure of titration.

    2. learn that the end point of titration will be a colorless solution.

    3. discover sources of Vitamin C.

    4. collect data as to how many drops were needed for the indicator to become colorless.

    5. participate in hand-on activities.

    6. learn that science can be fun.

     

    Background:

    The chemical procedure of titration will be used to test for Vitamin C. Titration involves adding a test liquid, drop by drop, to an indicator solution that undergoes a series of color changes as Vitamin C is added to it. Students will work with a partner recording the number of drops required to change the color of the indicator. The point at which the indicator becomes colorless is called the end point.

    Two different indicators will be shared.

    Cornstarch-iodine solution - Even though iodine is a poison, it is used in water treatment and much safer for children to use and dispose of. On a previous day the teacher should make the cornstarch-iodine solution. Mix 2 tablespoons of cornstarch in 500 ml of water to make a cornstarch solution. Filter the starch solution through 2 to 4 of the thicker brand paper coffee filters until you have a clear liquid. The solution may be clear to slightly cloudy, but should not be milky white. Now add tincture of iodine by drops with constant stirring until the solution turns a deep, dark blue. If you add too much iodine, the solution will become brownish.

    Di-chloro-indophenol solution - The indophenol solution used in class is so dilute that it is safe for students to use. However, the concentrated powder can be harmful, and you will need to be careful not to get the powder on your skin or in your eyes when mixing the solution. Tell the students to avoid getting the indophenol solution on their skin. If they do get some solution on their skin, they should wash the area immediately. Caution all students against tasting anything in the science lab. Also, do not allow students to pour any chemicals down the drain. They should be poured into a proper receptacle. Contact your school district, a chemical company, or township recycling for proper disposal. To prepare the indophenol indicator, use a flat, wooden toothpick as a scoop. From the wide end of the toothpick, mark a half inch (1.25 cm). Place the toothpick into the indophenol powder up to the mark and scoop up as much powder as will fit on that area of the toothpick. Place ten toothpick scoops of indophenol in a gallon container and fill with tap water. Test the approximate concentration of the solution by adding a few drops of fresh orange juice to about 10 ml of indophenol solution. The indophenol solution should become colorless with about 4-8 drops of juice. Fewer drops indicate a dilute solution (add a scoop of indophenol), and more than 8 drops indicates a solution which is too concentrated (add more water). This solution should be stable for about a month, and should be enough to complete the tests with a class of about 25-30 students.

    Both solutions will work for Vitamin C testing. Though the colors of the two solutions are about the same, the intensity of the indophenol is much brighter than that of the cornstarch-iodine solution.

    Make sure you "swirl" the indophenol/cornstarch-iodine solution after the addition of each drop of juice. (A swirl is when you hold the container at the top and circle the bottom of the container to stir the liquid.)

    Make sure that all bottles are labeled.

    This lesson could be completed over several days. Day 1 could include a teacher demonstration of titration, with students repeating it as modeled. Other days could involve the testing of various juices.

     

    Materials:

    cornstarch-iodine solution or indophenol solution. Pour 10 ml of the indicator solution into clear glass or plastic vials or containers. One container for every 2 students, but a new container of solution will be needed for every titration test.

    container of 500 ml of water in which a 500-mg Vitamin C tablet has been dissolved.

    a variety of juices, including juices with and without Vitamin C (avoid using red or purple colored drinks - see the procedure) (Students can bring the juices in from home.)

    pipets - 1 for each pair of students

    white construction paper - 1 sheet for each pair of students

    data sheet - 1 for each student

     

    Procedure:

    1. The teacher will demonstrate the technique of titration and end point using a vial of indicator and dissolved Vitamin C tablet.
    2. Using a clean pipet, drop one drop at a time of juice into the indicator solution. One student can hold the vial of indicator solution, while the partner adds one drop of the dissolved Vitamin C tablet solution.
    3. The teacher should observe and swirl the container as a model for the students. Students must count each drop of juice that is added to the indicator until the indicator is colorless against a white background. This is the end point. (Please note: artificial colors in some drinks may tint the colorless solution. Avoid using red or purple colored juices, as it may be extremely difficult to see a color change in the indicator.)
    4. Demonstrate how students should record their results on their data sheet.
    5. Using the juices, students in groups of two should repeat this same experiment as modeled. The teacher will be observing the students, checking for their ability and understanding of the use of titration and end point.
    6. Students are now ready to titrate and test fruit juices for Vitamin C. Review the necessity for accurate note keeping using the data sheet.

     

    Critical Thinking Questions:

    1. Discuss the results of their experimentation. Possible questions may include: How many drops did it take to titrate the indicator with the Vitamin C solution? How many drops did it take to titrate the indicator with orange juice?, and How many drops did it take to titrate a juice with very little Vitamin C?

    2. What is the relationship between the number of drops of juice needed to titrate the indicator solution and the amount of Vitamin C in the juice? (The fewer drops required to titrate the indicator, the greater the amount of Vitamin C in the liquid.) (This may be confusing to some students, especially the younger ones, but more experimenting and other activities should reinforce this relationship and make it less confusing.)

     

     

    Activity 3: Analyzing and Graphing the Results

    Objectives:

    Students will:

    1. develop skills in analyzing and interpreting data.

    2. use a calculator to find averages.

    3. make a bar graph to show their results.

    4. learn scientific and nutritional information about Vitamin C.

     

    Background:

    The students will combine data from Activity 2, calculate averages, and construct a bar graph. Make one copy of the graphing sheet for each student. (Older more experienced students can make their own bar graph.) If an overhead transparency will be used to guide students with graphing, make necessary preparations ahead of time.

     

    Materials:

    calculators - 1 for each student, if possible
    completed data sheets from Activity 2
    graphing sheets - one per student
    colored pencils or crayons
    optional: overhead projector and transparency

     

    Procedure:

    1. In a class activity, the teacher will make a list of each drink that was tested on the board or chart paper.

    2. As the teacher goes through each drink listed, each group will report how many drops of the drink were needed to titrate the indicator, and the teacher will record that on the board next to the name of that drink.

    3. Students may notice that different groups have different results, even though they have tested the same juice samples. Have students explain why they think this occurs, and ask them what they think scientists would do if they had different results for the same experiment. Explain to students that scientists may redo the experiment, or they may investigate to find if there were any differences in the experimental procedure. They may also average their results, which is what the students are about to do.

    4. Have students average the class results using a calculator. If students do not know how to compute averages, you may want to explain how to do them and allow the students to practice.

    5. Have the students report the average results for each drink as the teacher writes the averages on the board or chart paper next to the name of each drink.

    6. Students will use the average results for each drink to make a bar graph. If students do not know how to make a bar graph, demonstrate by using the first drink listed on the board or chart paper, writing the name of the drink on the graph sheet, and coloring in a block for each drop that was needed to titrate the indicator (remember to use the average result). Now have students work in pairs to complete the graph sheet.

     

    Critical Thinking Questions -

    1. Have the students rank the juices in order from the juice containing the most Vitamin C to the juice containing the least amount of Vitamin C. Remind students that the more Vitamin C a drink contains, the lower the number of drops it takes to titrate the indicator.

    2. In their notebooks, have students describe what the results mean to them, and what conclusions they can make from the results. (They may describe what drinks they would choose if they wanted the most Vitamin C, and which they would avoid.)

    3. Why do we need Vitamin C in our diet? (See background material in the introduction of this article.}

     

     

    Activity 4: Testing Fruit and Food for Vitamin C

    Objectives:

    Students will:

    1. learn alternative sources of Vitamin C.

    2. practice the technique of titration.

     

    Background:

    See Activity 2: Testing for Vitamin C in Juice

     

    Materials:

    a variety of fruits, vegetables, and potatoes (Try to include a mix of foods that do and do not have Vitamin C such as oranges, apples, strawberries, bananas, lemons, tomatoes, etc.)

    indicator solution (cornstarch-iodine or indophenol)

    blender

    coffee filter paper

    pipets

     

    Procedure:

    1. Make solutions for each food either by squeezing the juice directly from the foods (such as with oranges and lemons), or by blending with water and filtering the pulp of the food through coffee filter paper. Place each food sample in a different, labeled container.

    2. Pour indicator fluid into enough bottles to test each food sample.

    3. Titrate food samples into the indicator solution dropwise, counting the number of drops needed to reach the endpoint of the titration.

    4. Record your data.

    5. Graph the recorded data.

     

    Questions for Critical Thinking:

    1. Which foods contain the most Vitamin C?

    Journal Writing:

    2. If you were planning a meal rich in Vitamin C for your family, which foods would you want to include?

     

     

    Activity 5: Another Vitamin C Test using Potatoes

    Objectives:

    Students will:

    1. learn sources of Vitamin C

    2. participate in hands-on activities.

    3. learn that science is fun.

     

    Background:

    In Activity 1, students learned that potatoes contain starch. In Activity 4, they learned that potatoes also contain Vitamin C. In this experiment, instead of using titration, the students will put the potato slice in the indicator solution and mash it until the indicator becomes colorless.

     

    Materials:

    For each pair of students:

    indicator solution (cornstarch-iodine or indophenol) in a clear container

    a slice of potato (Idaho potatoes work best for mashing)

    utensil for mashing (i.e. wooden skewers)

     

    Procedure:

    1. Place potato slice in indicator solution, which should be blue.

    2. Begin to mash the potato in the solution until the blue indicator solution turns clear. This color change indicates the presence of Vitamin C.

    (Precaution: Avoid splattering of indicator solution. Caution children against vigorous mashing to avoid splattering of indicator solution. Eye goggles are a must!)

     

    Questions for Critical Thinking:

    1. Should potatoes be considered an important part of many meals? Why?

     

     

    Activity 6: Analysis of Vitamin C Lozenges

    Objectives:

    Students will:

    1. develop an understanding of the importance of Vitamin C in their diet.

    2. name a commercial source of Vitamin C.

    3. participate in a hands-on activity.

    4. learn that science is fun.

     

    Background:

    This lesson provides an opportunity for students to learn that in the United States, the recommended daily allowance (R.D.A.) of Vitamin C is 60 milligrams. In today's society, you may purchase lozenges that contain the U.S.R.D.A. of Vitamin C.

     

    Materials:

    Vitamin C lozenges, 60 mg
    water
    indicator solution (cornstarch-iodine or indophenol)
    pipet

     

    Procedure:

    1. Dissolve the lozenge in 60 ml of water.

    2. Pour the indicator solution in a separate container.

    3. Children should predict how many drops will be needed to reach the end point.

    4. Using a pipet, add the lozenge solution to the indicator bottle dropwise.

    5. Count and record the number of drops needed to observe a color change in the indicator solution.

    Optional: If you are using indophenol as the indicator, you may want to save one titrated indophenol solution for reoxidation using an aquarium air pump. This may revert the color of the solution to blue. In a less concentrated solution, this may also occur in the bottle of solution overnight without the use of the air pump.

     

    Questions for Critical Thinking:

    Journal writing:

    1. Why would manufacturers produce a lozenge that you can carry on your person?

    2. Why would manufacturers produce a lozenge that contains exactly 60 mg of Vitamin C?

     

     

    Activity 7: Food Oxidation Tests

    Objectives:

    Students will:

    1. develop an awareness of the use of Vitamin C in helping our environment.

    2. participate in hands-on activities.

    3. learn that science is fun.

     

    Background:

    In previous activities, students learned that potatoes contain Vitamin C. In this activity, students will learn that potatoes and some other foods do not contain enough Vitamin C to prevent oxidation (which will cause them to turn brown). In Part A of the Procedure, both sets of potatoes will eventually turn brown due to oxidation. The slow rate of oxidation of the potatoes covered with ascorbic acid powder is due to the ascorbic acid (Vitamin C), which is an anti-oxidizing agent. (Please refer to paragraph #3 of the Introduction.) Students will see how Vitamin C can be useful to our environment by protecting food from oxidation. Note: Apples may contain preservatives for shipping purposes, which may deter the apple from browning.

     

    Skit:

    To help students understand the processes of oxidation and anti-oxidation that will be observed in this activity, they may perform the following skit. The teacher should prepare (or have the students prepare) signs (1 for each person) with one of the following words: ASCORBIC ACID (VITAMIN C), POTATO, APPLE, BANANA, and OXYGEN.

     

    Part 1

    Each student holds up their sign and acts out their part as the teacher narrates what will happen in the process of oxidation, and then anti-oxidation. Students portraying the roles of POTATO, APPLE, and BANANA will assume a position somewhere in the classroom. Those students portraying the role of OXYGEN will surround the foods, and "attach" to them by holding their hands. This represents oxidation. Students may return to their seats for a discussion.

     

    Part 2

    Foods will assume their original skit positions, but this time, those portraying the role of ASCORBIC ACID will "attach" to the foods by holding their hands. OXYGEN will try to penetrate the foods, but they will not be able to "attach" to them because ASCORBIC ACID is already attached, and will prevent the oxygen from attaching to the foods. This represents anti-oxidation. Students will return to their seats for a discussion.

    Now students will have an opportunity to witness these processes through a hands-on experiment.

     

    Materials:

    Part A

    For each pair or group of students:

    potato pieces, mashed up and divided into two separate containers (Idaho potatoes work best)

    ascorbic acid (Fresh Fruit brand powder)

     

    Part B

    For each pair or group of students:

    1 apple

    1 potato (Idaho potatoes work best)

    1 banana

    1 lemon or lemon juice (use with a pipet)

    ascorbic acid powder (Fresh Fruit brand powder)

    knife (should be used by the teacher, not the students)

     

    Procedure:

    Part A

    1. In one container of mashed potato, cover the potatoes with the ascorbic acid powder.

    2. Do nothing to the other container of mashed potatoes.

    3. Let the two containers sit for a while.

    4. Notice any changes and continue to check on the potatoes every 15 minutes or so, recording your observations.

     

    Part B

    1. Cut the apple, potato, and banana in thirds.

    2. Sprinkle 1 third of the apple, the potato, and the banana with ascorbic acid powder.

    3. Sprinkle 1 third of the apple, the potato, and the banana with the lemon juice.

    4. Leave the final third uncovered.

    5. Leave the food slices exposed to the air overnight.

    6. Next day, examine the food slices for browning, due to oxidation, and record your results.

    Please note: Oxidation is an irreversible process. Make sure students understand that once fruits have been browned (due to oxidation), adding ascorbic acid powder will not return the foods to their original freshness.

     

    Questions for Critical Thinking:

    Journal writing

    1. Tell what the results of this experiment mean to you.

    2. How could we model the oxidation of food in a labeled drawing? (Refer students to the skit.)

     

    Assessments:

    Pre-assessment - To find out what your students know about Vitamin C, you can use a KWL chart. KWL represents What you Know, What you Want to know, and What you Learned. This can be completed individually or as a class.

    On-going assessment - The teacher should be listening, observing, asking questions, and possibly using a checklist to keep account of student achievement.

    Post-assessment - Several assessments have been included here for your choice.

    1. Students can complete the L part of the KWL chart.

    2. "What are the Big Ideas (important concepts) that you feel are important from our study of Vitamin C?" (This could be discussed with the entire class or as an individual assignment.)

    3. A more formal written assessment is included. This could be changed to suit your needs.

    1. You are eating corn-on-the-cob and wonder if it contains starch. Describe how you would test the corn to see if corn has starch in it. Use drawings to help explain your description. (Use this assessment only if you used the cornstarch-iodine solution.)
    2. Explain the process of titration so a new student can test for Vitamin C.
    3. Write an advertisement for a radio show telling why Vitamin C is important to human health.
    4. Make a list of foods you would suggest to your parents to make sure your family gets its recommended daily requirement of Vitamin C.

    4. Checklist or Rubric

    1. Worked cooperatively with partner.
    2. Completed his/her science notebook and made labeled drawings.
    3. Participated in class discussions.
    4. Demonstrated the chemical process of titration.
    5. Explained what was done.
    6. Made reasonable predictions.
    7. Followed directions.
    8. Completed a graph.
    9. Analyzed and interpreted data.

     

    Teacher and Student Resources:

    Benchmarks for Science Literacy

    American Association for the Advancement of Science
    Project 2061
    1993

    My Side of the Mountain

    Author: Jean Craighead George
    Puffin Books, Viking Penguin, New York 1991
    E.P. Dutton, New York 1959

    Grades: 5-12

    This story tells of a boy's adventures alone in the mountains of New York. He suffers symptoms of scurvy (a Vitamin C deficiency), such as nosebleeds, during the winter as his food is running out. This experience is described in depth on page 142 (Penguin) or page 134 (Dutton).

    This book won the Newberry Honor, ALA Notable Book, and the Hans Christian Andersen International Award.

    * This story would be an excellent introduction into investigating Vitamin C. Just be aware that the scurvy section is toward the end of the book. Students really enjoy the story.

    There is a video of the story, which is excellent, but does not include the Vitamin C deficiency section.

    Russell Sprouts

    Author: Johanna Hurwitz; Illustrated by Lillian Hoba
    Morrow, New York 1987
    Viking Penguin, New York 1989

    Grades: 1-4

    In this last chapter, "The Science Project", Russell's first grade class learns about plants and vitamins. Since potatoes contain Vitamin C, Russell chooses to sprout a potato. His positive attitude that science is fun involves his whole family in his project.

    * This is an easy chapter book that could be used as an introduction to the study of Vitamin C, especially for younger students.

    Oranges

    Author: Zack Rogow, Illustrator: Mary Szilagyi
    Franklin Watts, New York 1988
    Grades: K-5

    In this book, the process of taking an orange from the tree through getting it to one's home is described.

    The book also tells how people must work together so that people in all areas and during all seasons may have constant sources of Vitamin C rich foods.

    June 29, 1999

    Author: David Wiesner
    Clarion Books, Houghton Mifflin Co., New York 1992
    Grades: 3-6

    As a science project, Holly grows vegetable seeds in space. Students may realize from this book that sometimes there may be unexpected experimental results.

    Elliot's Extraordinary Cookbook

    Author: Christine Bjork, Illustrator: Lena Anderson
    Farrar, Straus & Girroux, New York 1990

    Grades: 3-6

    This is a good book for teaching about food and nutrition. With the help of a neighbor, Elliot cooks wonderful recipes, and investigates foods that are healthy and not healthy. Elliot also learns about proteins, carbohydrates, the history of chickens, and how cows produce milk.

    Vitamin C Testing, Teacher's Guide

    Author: Jacqueline Barber
    Lawrence Hall of Science, University of California, Berkeley, California 1988

    Grades: 4-8

    This book gives a complete investigation of Vitamin C testing using the chemical indophenol.

    The Science Chef

    Authors: Joan D'Amico and Karen Eich Drummond, R.D.
    Illustrator: Tina Cash-Walsh
    John Wiley & Sons, New York 1995

    Grades: 2-6

    This book contains 100 fun food experiments and recipes for kids. It answers the question, "Why does a cut apple turn brown?", with an experiment preventing browned fruit. Then there are four recipes using orange juice to prevent the fruits being used from turning brown. Another experiment related to this theme answers the question, What's so special about potatoes? This is a good book for teacher and students.

    Kitchen Chemistry

    Authors: John Bath, Ph.D. and Sally Mayberry, Ed.D.
    Illustrated: Catherine Yuh
    Carson-Dellosa, NC 1994

    Grades: 4-6

    This book contains 39 basic science experiments designed around readily available, inexpensive materials found in the home. Two experiments related to this theme would be Testing for Vitamin C and Testing for Starch. Younger children could complete these experiments under proper guidance.

    First Connections, CD-ROM Children's Encyclopedia

    A Renaissance in Learning
    Jostens Learning

    Under Vitamins and Minerals there is information that would be quite suitable for students to find and read.

     

    Web Sites:

    http://www.apsu.edu/sites/apsu.edu/files/chemistry/SP11_1021_ANALYSIS_OF_VITAMIN_C.pdf - Analysis of Vitamin C

    http://chem.lapeer.org/Chem1Docs/VitCAnalysis.html - Analysis of Vitamin C

    http://chemmovies.unl.edu/chemistry/beckerdemos/BD047.html - Vitamin C in Fruit Juices

    This experiment is courtesy of 



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