THE SPREAD OF AIDS
1993 Woodrow Wilson Biology Institute
This is a hands-on activity that simulates the spread of a disease such as AIDS. Students will become aware of the rate at which AIDS can spread within a population.
TARGET AGE/ABILITY GROUP:
Secondary level, all ability levels
STUDENT/CLASS TIME REQUIRED:
- bathroom (paper) cup/student
- disposable pipette/student (If pipettes are
unavailable, students can carefully pour a small
amount of the liquid between cups.)
- graduated cylinder
- 10 ml of 0.1 M NaOH for one student who is the
only one to be a carrier/class (0.4 grams of NaOH
dissolved in enough water to make 100 ml of
solution) or 10% solution of Liquid Drano (10 ml
of Drano plus 90 ml of water)
- 10 ml of water each for all other students
- phenolphthalein solution in dropper bottle or
with a pipette (indicator for basic solutions)
TEACHER GUIDE FOR
For each 24 students, select one student to be the "carrier"; this student will receive the cup with the 10 ml of NaOH solution. Do not tell this student that the contents of his cup are different. From this one student, a maximum of 12 other students can receive the "infected" solution. Into all other cups put 10 ml of water.
PREPARATION OF MATERIALS:
- Hand out cups and pipettes (optional); one
student gets "infected"cup and all others get
- After students have made exchanges of fluids,
walk around and pipette several drops of
phenolphthalein solution into each student's cup.
- Students are to transfer "body" fluids three
times by using pipettes to exchange a small
amount of liquid between cups with three other
- Keep track of those students with whom you
exchanged solutions by writing their names on
- After three exchanges are made, teacher
will put indicator solution (phenolphthalein)
into each student's cup. A pink color indicates
- Those students whose solutions changed to a
pink color should determine from whom they
received the "infection" (really the NaOH
* Eventually the class can determine the one
student who had the original "infection."
- Determine the number of students who had pink
solution in their cups at the end of the activity.
- Calculate the percent of those students in the
class who have the "infection".
- Make a drawing to show the pyramiding effect
of the spread of the "infection" within the
- Discuss reasons why diseases can spread
so quickly and ways to control the spread of
diseases such as AIDS.