Biology - HOT Science Lab

Teacher
b. An asterisk (*) is placed next to each name in the Class Data Table who
was found positive for the simulated disease. The Data Table above shows
that Bob exchanged with Beth, Mary, and Janet. This shows that in round 1,
Bob did not have the disease when he exchanged fluids with Beth (because
she tested negative), but received it in Round 2.
c. The Class Data Table is then used to devise a flow chart and to trace the
route of transmission. In Round 1, Dave and Mary, have tested positive for
the disease. This indicates that these two people were involved in the
original exchange.
d. In Round 2, Mary and Dave exchanged ―Simulated Bodily Fluids‖ with Bob
and Andrew. The flow chart now shows two rounds of exchanges and a
total of four infected people.
e. For Round 3, the names of the individuals that exchanged with Bob,
Andrew, Mary, and Dave are filled in. They were janet, Jennifer, Karen, and
john, respectively. This completed flow chart shows that in Round 2, four
people had the disease, but in Round 3, the number of infected people has
doubled to a total of eight people. Thus, the disease has passed from an
original exchange of two people, to a total of eight people.
Example Route of Transmission Flow Chart
The chart above shows that in Round 1, Mary and Dave exchanged fluids.
Since they are both positive in Round 1, they pass on the disease to Bob and
Andrew in Round 2, and to Karen and Jennifer in Round 3. Then Bob and
Andrew pass it onto Janet and John, respectively. In an actual epidemic
situation, one cannot trace a disease as easily as in this simulation. In an open
system, it is almost impossible to trace a disease back to an original carrier.
Because the class is a closed system, we can trace back to an original
exchange. If you had completed another round of ―Simulated Bodily Fluid‖
exchange, then 16 people would be infected; with each round of transmission
the number of infected people doubles.
Extension:
Gizmo: Disease Spread
Biology HSL Page 147
Curriculum and Instruction