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| WV State Standards: |
Math:
M.O.PS.5.1, M.O.PS.5.2, M.O.PS.5.9, M.O.PS.5.11
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Science:
AES.2.1, AES.2.3, AES.2.4, AES.2.5, AES.2.7,
AES.2.8, AB.1.4, AB.6.6
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Technology:
TEC.9-12.3.1, TEC.9-12.3.4, TEC.9-12.1.1
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| National Standards: |
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Science:
5, 6, 11, 12, 13
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| Blooms Taxonomy: Knowledge, Synthesis,
Evaluation |
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21st Century Skills:
Creativity and Intellectual Curiosity
Critical Thinking and Systems Thinking Problem
Identification, Formulation, and Solution
Thinking and Problem Solving Skills
Communication Skills Interpersonal and
Collaborative Skills
Social Responsibility
Self Direction
Adaptability |
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Objective(s)
- Collecting samples of contaminants on both
treated and untreated surfaces
- Inoculating sterile culture media with the
collected samples
- Stating hypotheses about the effectiveness of
treatments
- Observing and summarizing the results of
experiments
- Replicating procedures using different
treatments
Time Required
One 90- minute class or block schedule or Two
45-minute class periods
Pre-Requisite Skills
Proper bacteria collecting procedures
21st Century Tools (Technology Tools)
- Computer lab with Internet access
- PowerPoint software
- overhead projector
Instructional Materials
- Computer lab with Internet access
- 10 Petri dishes with sterile culture medium per student
group;
- 5 sterile alcohol pads/wipes per student group;
- Hand-sanitizing gel;
- sterile cotton-tipped swabs with plastic shafts (such as
Q-tips) that can easily be snipped off;
- one sample of Silestone with Microban per group;
- one Aegis antimicrobial product sample per group;
- 2 rolls cellophane tape per group;
- two pairs scissors per group;
- 2 grease marking pens per group, for labeling glass
Petri dishes;
- one pair latex or other gloves per student.
- Digital cameras – one per group
- Distilled water
Procedure
- In assigned teams of 4-6 members,
students will visit local retail shopping centers.
- Carrying Petri dishes, relevant equipment
and materials, each group of students will randomly select
shopping carts that have been recently and extensively used.
(Carts that have recently been out in the rain and/or
sunlight should be eliminated from the sampling.)
- Using rubber gloves, each group of
students will collect samples of microbes on 2 untreated
handles by using a cotton-tip swab dipped in sterile water
(distilled water) and swiping along the entire top surface
of the cart handle. Using scissors, each contaminated swab
tip will be snipped off onto one opened agar-plate, the lid
immediately replaced, secured with tape, and labeled with a
grease pen as to Group Number, type of treatment (No
Treatment in this case), date, time and place of
collection. Repeat on a second cart using the other end of
the swab.
- AFTER either using the two carts in Step
3, or selecting two more, students will thoroughly wipe the
cart handles with packaged alcohol swabs. After alcohol has
dried, repeat the sampling twice with cotton-tipped swabs,
placing the exposed swab tips on culture medium and again
labeling as in Step 3 above.
- Next, students select two more untreated
carts and clean the handle areas with hand-sanitizing gel.
The same cotton-tip swab sampling is performed and tips
placed on two more agar plates and labeled. This ends the
portion of the experiment performed in a shopping mall.
Students collect their materials and return to class.
- Next, students use the two commercially
available products and without altering their surfaces, both
are swabbed similar to the shopping cart handles. The
cotton-tip swabs from this sampling are also placed on the
surfaces of two agar plates and labeled accordingly.
- All cultures are now taken to the growth
chamber to await the results. At the beginning of each
class period, students should examine their dishes for
evidence of growth – or not!
- Students will wash their hands frequently
when finished working with their samples. Students can
check out the following experiment on
Hand Washing.
- Have students summarize their procedures in a
PowerPoint presentation.
Differentiated Instruction
As IEPs may
dictate; also be aware of students with allergies to latex if
using latex gloves for sampling. Ninth graders may not have
experience with sterile culture media, and may need additional
instruction for handling these laboratory materials. Also, a
guest speaker could be added to the schedule, before, during or
after any of the lessons.
Author's Comments
Reserve a
growth chamber with the biology department; order adequate
number of Petri dishes with culture medium; purchase
Hand-sanitizing gel, cotton-tipped swabs, cellophane tape and
pens; arrange to have students transported to a local shopping
mall to collect samples; remind students to save their
PowerPoint work as they will be adding to it during ensuing
lessons. Contact managers of stores where students will collect
samples and solicit cooperation and permission for this project.
Students groups should be assigned a number for identification
on their culture plates.
21st Century Assessment/Evaluation
Evidence of
successful collection of samples.
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