# immune system lab

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Achooooo
Introduction
A particular type of curve is common in investigating situations such as the rate of bacterial
growth and the spread of disease. For example, as a virus spreads over time, the rate starts
increasing slowly, accelerates rapidly and then levels off to a maximum value.
Procedure
1. Assign everyone a number from 1 to the total number of participants. This is your number.
Whenever it is called out, you must stand to indicate that you’re infected. We will use the number
generator found on this site: http://www.random.org/integers/
2. For each infected person a new random number must be drawn. This person represents the
newly infected person, who must now stand.
3. After each trial, record in a table the total number of people infected (standing).
4. Repeat this process for 10 trials.
5. Repeat entire experiment, but this time draw 5 numbers to indicate the students who have
received a vaccine to the disease. Whenever their numbers come up, they remain uninfected (seated).
Data
Trial
0
No vaccine
1
1
2
3
4
5
6
7
8
9
10
# sick
Vaccine
1
# sick
Graph data on EXCEL spreadsheet using trial number on x axis and # sick on y axis.
Analysis
1.
2.
3.
4.
5.
Using the shape of the graphs, explain how disease seems to progress in both scenarios.
How do you think increasing the number of people will affect the shape of the graph?
What is the impact of vaccination on public health?
What other factors can individuals do to prevent the spread of disease?
How can you apply the spread of this viral disease to the spread of a bacterial disease?
Conclusion
1. Write a paragraph explaining why you think the number of people being infected by a disease
seems to “level out” over a period of time.
2. In a real world situation, what factors increase the rapid spread of disease? What factors reduce
its rapid growth rate?
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