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Grades 9 - 12


One of our country's greatest health challenges is infection with HIV, the virus that causes AIDS. Today most of the people with AIDS are young adults. In this lesson, students will discuss ways to avoid contracting HIV and then participate in an activity which models the rate of growth of a communicable disease within the community. Students will collect data, display a graphical representation of the results of the simulation, and make predictions about future results based on the logistics function they discover.

[AIDS education may be controversial in your community. Parent permission may be desirable before using this lesson. The mathematics used in this lesson could also be adapted to any communicable disease (such as hepatitis).]
ITV Series
Right Turns Only: Alcohol and Other Drugs and At-Risk Behavior Concerning AIDS & Teenage Pregnancy (Lesson #105)
Learning Objectives
Students will be able to:
Per student group of 3-4 students

Per student

Pre-Viewing Activities
The teacher should set a serious tone for the classroom by saying, "It has been said that making small mistakes in life are good learning experiences, but making large mistakes can take years to recover. We also know that taking major risks in the way we live our lives can be very costly for ourselves and our families. These risks have been changing over the years. Think about the lives your parents and grandparents led. How do they compare with the experiences you encounter? Let's take a few minutes and work in groups of 3-4 students to generate a list of Life's Difficult Challenges faced by people in the 1960's and those faced by you today in 1996." Provide each student group with 10 pieces of colored paper (5 each of two different colors) and a marker. Give students approximately 10 minutes to brainstorm the difficulties people faced during the 1960's and those they face today, in 1996. Each group will record a different 'Life Challenge-'60s' on one color of paper and a different 'Life Challenge-'96' on a different color. During this discussion, the teacher should make two large category headings on the board. The headings are Life Challenges-1960's and Life Challenges-Today.

After students have completed recording their ideas say: "Now let's share your ideas. Go to the board and tape your ideas beneath each heading so that other students can see them."

Begin with one group. Discuss the ideas as they are posted. Allow the second group to tape their ideas to the board. If they have the same or similar idea shared by the Group 1, they should tape their colored paper over that matching Group 1. Continue until all groups have shared their 10 ideas. Allow for student discussion. In most cases, students will suggest a medical life challenge, particularly the HIV virus and/or AIDS. If this was not suggested, the teacher should offer it as a possibility and allow students to share ideas around AIDS as a life challenge. Suggest that education can have a dramatic effect in helping reducing the risk of contracting this very serious disease.

Say, "One of the ways we can educate others about HIV and AIDS is through video programming. We are going to watch a video that was produced to help students recognize risks we all face in life. This educational product can provide information to help each of us make good decisions about avoiding hazardous life challenges."
Focus Viewing
To give students a specific responsibility, say: "As you watch the segment Right Turns Only, write down any information you hear that would help someone understand more about HIV and AIDS." START tape at the beginning of the Right Turns Only heading.

Viewing Activities
PAUSE tape after TV teacher explains how AIDS is transmitted. Say, "Were you aware of the ways in which AIDS is transmitted?" Allow students to answer and encourage discussion. Say, "What other questions might be in the minds of these students in this class?" Write suggested questions on the board and say, "Let's see if these students thought of the same questions. " RESUME tape and PLAY until the end of the first question, "So we can't really get AIDS just being around somebody?"

PAUSE tape and verify that students had included that question or add it to their list of questions.

RESUME tape and play until the end of the second question: "What about kissing?" Compare this question to those generated on the board. Discuss possible answers to this question.

RESUME tape and verify the answer to the 'kissing' question. PLAY until the school bell rings and the street sign Right Turn Only appears. STOP tape.

Say, "In your groups, make a list of the dangers encountered when participating in the activities which transmit AIDS. These should be ideas that these students could include to make a more powerful video presentation about the dangers of sex and needle-sharing. " As students are discussing these connections, FAST FOWARD tape through the separate discussions between the young men and the young women. When the Right Turn Only sign appears again, PAUSE tape. Have students share their ideas and record this list on the board. (Be sure the list includes teenage pregnancy and dangers to unborn babies by drug-using mothers.)

To compare the class list to the ideas generated by the video project, RESUME tape and play until the doctor says, "Don't take the chance. Don't roll the dice with your life or your baby's life." PAUSE tape.

Say, "We are now going to see how the 'roll of the dice' can help us understand how quickly a disease, such as AIDS, can spread in our community. Our class will assume the role of a group of doctors at a medical convention. As a doctor, you are involved with the prevention and cure of AIDS. During this convention, each of you will represent one of your patients who may be at risk of contracting HIV. We will assume that you have no information about this patient."

Distribute Medical Convention Worksheet and one die to each student. Have one of the students read the introductory paragraphs on page 2 of the worksheet. (Students should complete the sentence listing the two main ways of spreading HIV.)

Say, "We are now going to create a mathematical model that shows how the HIV virus can affect our patients. As doctors, we must respect the confidentiality policies of our patients. To do this, we will refer to our patients using case numbers only. You will be unaware of the age, gender, and behavior patterns of the person you represent. Now, roll your die five times and record each roll as one of the digits of your case number. " After students have completed this step, have them list each case number in a matrix on the board, organizing the list by the first digit of the case numbers. Example Matrix:
1 2 3 4 5 6

Say, "We will now examine the growth of HIV/AIDS, using a die to simulate the behavior of our case study patients. During each of the five timed intervals, you will circulate through the room and meet several different subjects (other people). As the music begins, introduce yourself to someone in the room. Each of you will record one another's case number in 'Timed Interval 1.' To simulate patient behavior, have one person toss one die. If a 1 or a 6 appears, both individuals circle the case number recorded on the worksheet. This represents Risky Behavior. If a 2, 3, 4, or 5 appears, each person will cross off the case numbers they recorded. This represents Safe Behavior. Then move on to a different individual, repeating the same simulation, recording case numbers and indicating Risky or Safe Behavior (by circling or crossing off the case number) in Timed Interval 1. Continue meeting new people until the music stops. " The teacher will play one 2-3 minute song (or time 2-3 minutes). (As students participate in the simulation, the teacher should FAST FOWARD the video tape through the student dance and the interviews with the teenage moms. As the young man asks for the video camera to make an AIDS commercial, stop the tape - to be resumed at this point after the viewing activity.)

Say, "We will now continue the simulation but will record our data in Timed Interval 2. Continue in this same manner, meeting new people as well as previous encounters, recording case numbers and safe and risky behavior as you did during the first timed interval."

PLAY a second song or time 2-3 minutes. At the end of this time period, direct students to continue in the same simulation, but record data in Timed Interval 3. PLAY a third song. Continue in this manner through five timed intervals. This should take approximately 15 minutes.

Upon completion of the data collection, discuss the following questions: 1. What are the probabilities associated with the Risky Behavior and the Safe Behavior of our case studies? Does this numerical value seem reasonable? 2. How many case studies do you think will be infected at the end of each timed interval? Record prediction. 3. Do you think an aggressive education program may change these results?

After a discussion of these questions, say: "We are now ready to record the results of our simulation on the graph on page 4 of your Medical Convention Worksheet. Let's suppose that one of the case studies was actually infected with the HIV virus. We will select that person randomly."

The teacher should toss a die, matching each digit of the case numbers until a unique individual is determined. Say, "Since we have made the decision to begin the growth of this function with 1 infected individual, plot the value 1 for the beginning of our experiment (Timed Interval 0)." Direct attention to the case study numbers recorded in the matrix on the board. Circle the case number of the randomly selected infected person.

Say, "Look at the information you gathered during Timed Interval 1. Raise your hand and report your case number if you had RISKY BEHAVIOR with the infected person." Circle these new case numbers in the matrix and plot the total number of infected patients on the graph at Timed Interval 1. Direct students to Timed Interval 2 and say, "Raise your hand if you had RISKY BEHAVIOR with any of the infected patients from Timed Interval 1." Circle these newly infected patients and record the cumulative number of reported cases on the graph at Timed Interval 2.

Continue in the same manner through the remaining Timed Intervals. Complete the graph by plotting the remaining points and then discuss the results. (If the mathematics background of the students is appropriate, use a graphing calculator to determine the equation of the regression line. Discuss predications and the logistics curve.)

Say, "We can see how quickly an infectious disease can spread through a community. We can help reduce the risk of contracting a disease like AIDS by educating others. We must help everyone understand how a partner's former or current behavior can affect our own health." To give students a specific responsibility while viewing, say: "As you watch the commercial made by the young students in this program, decide if the message is strong and clear enough to encourage viewers to eliminate Risky Behavior in each of their lives"

RESUME tape and play to the end of the show. Have students discuss the strengths and weaknesses of this student-made commercial.
Post-Viewing Activities
Repeat the simulation using only 1 number to represent Risky Behavior. Ask students to predict the growth of this function with a risk factor of 17% rather than the 33% used in the first simulation. Compare and discuss these two models. Discuss the following questions in small groups and share the ideas with the entire class: 1. Do you think a good educational program around these risks would help save lives? 2. What type of educational program would be most effective?

Have students make a brochure that educates their peers about the dangers of the RISKY BEHAVIOR which could result in the HIV virus. Include graphs, information, and research that would impact the reader. Share these brochures with other students in the school.
Action Plan
Design a Town Meeting in your school to help educate all students about one of our country's greatest health challenges--HIV/AIDS. Obtain a speaker phone and provide students with the opportunity to make a Classroom Call to the CDC National AIDS Hotline at 1-800-342 AIDS.

Make your own video, similar to the one made by the students in Right Turns Only, which helps educate your community about these issues. Contact your local television station for possible distribution on a local access channel.
The growth of infectious diseases is an exponential function. Explore other real-life applications of exponential growth and decay.

Use a spreadsheet to make radical and subtle changes in the parameters of the 'growth problem.' Compare and contrast the results of these changes.

Research other communicable diseases which have affected communities. How has medical research intervened in these situations?

Language Arts
Read current prose and poetry written by people who have contracted AIDS.

Master Teacher: Marilyn Stor

Click here to view the worksheet associated with this lesson.

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