Germ Wars: The Spread of Disease
Grades 5 through 12
Directions: Main Points/Rationale
During this lesson, students will learn about how certain diseases spread, and do follow
up research to learn about a specific disease.
Objectives
1. Students will participate in an activity to learn about how some diseases spread.
2. Students will research a disease and report their findings to the class.
PA Standards
History: 8.1.12C, 8.1.6A, 8.1.9C, 8.4.9A, 8.4.12A
Health, Safety and Physical Education: 10.1.12A,E
Science and Technology: 3.1.10E, 3.1.2E, 3.2.7A, 3.2.12A, 3.6.7A, 3.6.10A
Materials & Equipment
Small cups
Flour
Baking soda
Vinegar
Research Materials: library, internet
Warm-Up – 3-5 minutes
Ask the students what they know about how diseases spread. Are diseases airborne?
What are some airborne diseases you are familiar with? Do you have to touch the
infected person to catch a disease/ explain? Do you have to come in contact with bodily
fluids? Can a parent pass a disease to a child? How do you know if a disease is bacterial
or viral?
Activity One –– 20 minutes
1. Have one small cup for each student in the class.
2. Have most (90%) of the cups each filled about 1/3 with flour, and fill about 10% of
the cups 1/3 each with baking soda.
3. Distribute the cups randomly to the students, not telling them what is in the cups.
4. Instruct the students that they are going to walk around the room and “meet” other
people in their class. To meet someone, they must mix the contents of their two cups
together and then evenly split it between their two cups.
5. Give the class about 5 minutes to walk around and meet other classmates. When time
is up, have the students return to their seats.
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Now you can tell the class that 90 % of the cups had flour in them, which meant that the
person holding them did not have the mystery disease. Some had baking soda, which
represented the mystery disease. If you met someone with the disease and mixed the
contents of your cup, you are now infected with the disease. How can we test for the
presence of the disease? (Some may know that vinegar causes baking soda to fizz.) Walk
around the room dripping vinegar into everyone’s cups. Those that fizz are “infected.”
Make note on the board of how many cups you started with that were infected, and now
how many cups are infected (contain baking soda). Ask the students to answer the
following questions in writing:
Student Reflections Individually (written):
1. How did you decide who you wanted to “meet and mix” with?
2. How many people did you “meet and mix” with?
3. Could you tell by the physical contents of the cup if the person was infected?
4. What do you conclude about the spread of diseases and infections?
Extension activity for older students: Start with only one cup of baking soda and the rest
filled with flour, again not telling the students what is in the cups. Assign two people to
not participate in the experiment, but to represent the Center for Disease Control (CDC),
who will participate later. This time, the students are to meet only three people. On a
piece of paper, have the students keep track of who they “meet” with and in what order.
Once everyone has “met” with three people they are to sit down. Once all are done, the
CDC people will test each of the cups to see who is infected, keeping track on the board.
Have the CDC people try to figure out who was the original person infected by asking
those who are infected who they met and in what order.
Activity Two – – 15-20 minutes
Discuss your results. Explain that many infectious diseases are spread through contact,
even by shaking hands. This is what we just simulated. This is why washing hands is so
important in the prevention of disease. Go to http://www.collphyphil.org/teachers.html
for downloadable worksheets and information on infectious diseases.
Discussion Questions:
1. Can you tell just by looking at someone that they have an infectious disease?
2. Are there minimal precautions you can take around people to reduce the risk of
disease?
3. What is meant by the words “contagion” and “infection?” (A contagion is a disease
causing agent, such as a virus. An infection is what results in the host after coming in
contact with the contagion.)
4. List different ways that a person can get infected by a disease.
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Activity Three – –one class period (or as much time as needed), could be homework
Have the students each pick an infectious disease. (See list below for some examples)
Have them research the disease, where it originated, is it viral or bacterial, what its effects
are on the body, who is affected by it, and most importantly, how it is transmitted. After
the research is complete, have them report their findings to the class.
Discussion Questions:
1. How many diseases are transmitted by body contact? By sex? Through air? Through
body fluids?
Closing - 2-3 minutes
At your trip to the Mütter Museum, during your lesson, you will learn about some heroes
and heroines in medical history who have made advances in medicine and medical
practices. What medical practice did we learn during our exercise that is key to
preventing contagious diseases? Washing your hands with soap! Soap traps oil and dirt
inside a cluster of soap molecules called a micelle, which is easily rinsed away with
water.
Assessment of Student Performance
1. Are the students working together effectively? While they are “meeting” each
other, walk around the classroom to assess.
2. Were they able to find out the requested information about their chosen disease?
3. Collect their student reflections; use these to make sure you have corrected any
and all misconceptions the students may have.
Preparation for Post-visit lesson:
While at the Museum, be sure to visit the Benjamin Rush medicinal plant garden and see
what plants are growing there.
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List of some Infectious Diseases:
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HIV/AIDS
Tuberculosis
Malaria
Measles
Pertussis
Tetanus
Meningitis
Syphilis
Hepatitis
Smallpox
Cholera
West Nile Virus
Pneumonia
Dysentery
Herpes
Influenza (or flu), including H1N1 (Swine) flu
Mumps
Poliomyelitis
Rabies
SARS
Rubella
Typhoid
Typhus
Additional Information on infectious diseases:
Infections can be caused by such microbial agents as viruses, bacteria, fungi, protozoa,
and parasites. These agents are called pathogens, meaning capable of causing disease,
and are able to cause disease in humans, animals and/or plants. Viruses are very small
and simple microorganisms that consist of a protein coat and a core of RNA or DNA.
Viruses cannot duplicate themselves; they can only multiply inside of a host cell. An
example of a virus is the chicken pox or HIV. Bacteria are one celled organisms that do
not possess a nucleus. They can reproduce themselves by dividing in two. An example is
tuberculosis.
Infections can pass from person to person through several different mechanisms, called
direct and indirect. Direct transmission refers to any infection that occurs as the result of
direct contact between a pathogen and a host, or person. Usually they are closer than six
feet. There may be by “direct contact such as touching, biting, kissing or sexual
intercourse, or by the direct projection (droplet spread) of droplet spray onto the mucous
membranes of the eye, nose or mouth during sneezing, coughing, spitting, singing or
talking (usually limited to a distance of about 1 m or less).”(1) Gastrointestinal diseases
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are often contracted by eating or drinking contaminated food and water. Mothers can pass
certain diseases to their children via childbirth.
Indirect transmission occurs when the host and pathogen are separated, and require
some go-between for the organism to reach the host. This go-between is either called a
vehicle or a vector.
With vehicle-borne transmission, some infectious agents may be spread as a result of
contact with a contaminated inanimate object (known as a fomite), such as a coin passed
from one person to another. The most common fomite is the doorknob! A man sneezes or
coughs and covers his mouth. Then he opens a door. You come along and open the same
door and you have the germs on your hands. You eat a sandwich and you eat the germ!
A vector is any living organism that carries pathogens from one host animal to another
host animal. A vector works in two ways to spread disease: mechanical and biological.
Mechanical transmission involves physical surface contact. An example of a mechanical
vector is a housefly, which lands on the feces or a sick person or other animal and then
lands on food, carrying on its feet the pathogen from the feces. The healthy person eats
the food and gets sick.
A biological vector transmits a pathogen in an exchange of bodily fluids. An arthropod,
usually a mosquito, bites an infected animal. An arthropod is a jointed-legged animal
with an exoskeleton, and includes animals such as ticks, lice, mosquitoes and flies. The
pathogen enters the arthropod. It makes its way to the salivary glands of the arthropod.
The arthropod bites a person and the pathogen enters the body at the site of the bite.
Arthropods acting as biological vectors are often responsible for such diseases as malaria,
viral encephalitis, Lyme disease, yellow fever, African sleeping sickness, Rocky
Mountain spotted fever, and West Nile Virus.
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Resources:
• Notifiable Conditions: glossary of terms concerning communicable diseases,
sponsored by the Washington State Department of Health
o http://www.doh.wa.gov/notify/other/glossary.htm (1)
• MedicineNet.Com: their infectious disease center, with facts on many different
infectious disease topics, from anthrax to whooping cough.
o http://www.medicinenet.com/infectious_disease/focus.htm
• Diseases and Conditions: sponsored by the Centers for Disease Control and
Prevention, a list of top requested diseases and conditions with associated facts and
information.
o http://www.cdc.gov/DiseasesConditions/
• Infectious Disease Special Edition: sponsored by McMahon Publishing, features
cutting edge information in the advances of infectious disease control.
o http://infectiousdiseasese.com/
• Understanding Microbes in Sickness and in Health, sponsored by the National
Institutes of Health, a book entirely dedicated to what microbes are, and how they
make us sick.
o http://www3.niaid.nih.gov/topics/microbes/PDF/microbesbook.pdf
• A series of workbooks on infectious diseases, sponsored by the College of Physicians
of Philadelphia
o “Why Do I Get Sick? How Do I Get Better?” Grades 3-4
 http://www.collphyphil.org/workbookpdfs/gr3_4.pdf
o “Infectious Diseases and the Human Response” Grades 5-6
 http://www.collphyphil.org/workbookpdfs/gr5_6.pdf
o “Infectious Diseases and the Human Response” Grades 7-12
 http://www.collphyphil.org/workbookpdfs/gr7_12.pdf
Reviewed by: Dr. Mindy Langer; Jackie Harris, high school teacher; Michelle Thornton,
high school teacher; Robert Hicks PhD, Director, Mütter Museum/Historical Medical
Library
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