Pathogens and Transmission (Joshua Junkermeier)
Hook Videos:
NGSS Standards
HS-LS4-5
HS-LS2-2
HS_ETS1-1
Scientific Problems
1. How can we protect population from "germs" or pathogens?
2. What variables impact the size of our population?
3. Is there an "arms-race" between humans and pathogens?
4. How can we improve the designs of hygiene equipment to
reduce the transmission of pathogens?
Activity 1: cleaning produce
Students attempt to clean a potato.
.
Background: the potato is "dusted" with a UV-reactive powder that may or may not be removed from cleaning. The powder simulates a pathogen present on the food (food-borne illness).
Students take their food-potato and examine their effectiven
ess to remove pathogens from their food using a UV-flashlight.Equipment List: potatoes, "UV powder", and available sinks for washing.
Activity 2: Washing Hands to reduce transmission of Pathogens
Participants apply a "clear", UV-reactant paint to their hands.
UV-reactant paint simulates pathogens
Participants proceed to wash their hands as they usually do.
Following their hand rinse, students use the UV-flashlight to determine how effectively they washed their hands.
Followup Video: "best methods for hand washing"
Extensions 1: engineering an effective "air dryer"
Students can develop a design for minimizing the dispersion of pathogens.
Students can run tests with UV-paints (simulation of pathogens) to collect data on dispersion of pathogens.
Incubate cultures from swabbed hand samples.
Extensions 2: transmission of pathogens in the classroom
Video Link: classroom activity
Student volunteer(secretly) to act as a vector for pathogen transfer.
UV-flashlight can track their surface contacts and "infections" during a class period.
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Principles Illustrated:
Organisms interact within an ecosystem
Pathogen populations may increase when a vector population has a high-density distribution (density dependent variables).
Pathogens (bacteria, fungus, and virus) may experience natural selection as a response from human hygiene products and equipment.
Products can be improved in order to solve problems.
Organisms within a rapidly changing environment (pathogens) are likely to exhibit high reproductive rates as an adaptation for survival.
Bacteria may exhibit high mutation rates as an adaptation to selective pressures in the environment (hygiene products)
Prior Knowledge & Experience
This lesson may function as a "hook" into population ecology and density-dependent variables.
This lesson may function as an exploration with a cell biology unit. Students can investigate the relevance of cell-scale organisms sharing their habitat or community.
Students don't require prior knowledge to engage in the content or perform inquiry of the lesson.
Common Misconceptions:
Students may not know how effectively the wash their hands.
Students may not understand how effective the hygiene equipment and products are in restrooms.
Students may not understand the challenges of reducing food-borne illness and cross-contamination due to pathogens from hands and produce.