Sheila M. Martin-Corbin
Objectives
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Students will be able to understand how infectious disease spread through a population.
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Students will be able to identify behavior that increase or decrease the risk of infection.
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Identify and use the elements of scientific inquiry to solve problems.
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Use and interpret data collected to formulate conclusions.
Introduction
Pathogens are spread by a variety of vectors including the air, food, water and physical contact. This activity simulates disease transmission through exchange of bodily fluids in a manner similar to HIV and hepatitis. An infected person may or may not show symptoms of the disease and is referred to as a 'carrier' of the virus. Thus, a person being unaware and misinformed regarding his or her health, can impact the spread of a virus within a population.
Materials
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disposable cup
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disposable pipette
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tap water
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sodium bicarbonate
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phenolpthalein (indicator
Lab. Safety Measures
Students must wear safety eye goggles. Students must wash their hands after the lab. simulating activity. If there is a spill, students must wash the affected area with water. Students must NOT taste or smell any of the liquids used in the laboratory investigation.
Procedure
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Each student obtains a small vial containing a clear liquid and an eyedropper. Tell students that each vial represents their body and that one student is "infected" with a contagious disease. It is unknown to the students who that person is.
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Students will interact with a partner and simulate the exchange of body fluids by placing five drops of their liquid into their partner's vial without making contact with the other students' liquid or vial. (Both partners will fill up their eyedropper with liquid from their vial and place five drops into the vial of their partner).
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Students will move around the classroom and find another partner to exchange liquid with and avoid contamination with the liquids. Students will empty the remaining liquid into their vial and use their eyedropper to mix the liquid. Students will repeat steps #2 and #3 with five different students. and then return to his or her seat. Students can hypothesize the number of infected students for each interaction.
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Each student will test his or her liquid for the infectious disease by placing 1-2 drops of phenolphthalein, the indicator into his or her vial. If he or she tested positive, the liquid will turn pink. If tested negative, the liquid will remain clear.
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Have students record the cup number of the students that they interacted with in their charts, and create a flow chart to help them figure out who infected them and whom they subsequently infected. Also, eventually identifying the origin of the disease.
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The teacher will then record the results in a data chart on the chalkboard. Have students graph the number of infections versus the number of interactions. Students may estimate the number of infected students after 5 interactions. Students will notice that the number of infections seem to double with each additional interaction.
Exit Pass
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Students will discuss how this type of activity compare to the transmission of a real disease such as HIV.
Students will determine who infected them and who they subsequently affected.
Students will explain how an airborne disease would spread differently and why? Discuss ways of preventing or 'catching' an airborne disease.
Students will suggest precautionary measures that can be taken to prevent the transmission of infectious diseases.
Exchange Activity Sheet
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CUP Number
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Test Results (+/-)
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Your Cup
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First Exchange
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Second Exchange
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Third Exchange
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Fourth Exchange
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Fifth Exchange
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