Program Lesson Plan Template
This template should be used to prepare your project-centered lesson plan as a stand-alone .pdf to be distributed. Additional worksheets, diagrams, or pictures
(especially useful for complex setups) must be combined into this single document. This form is designed so you can also use it to copy and paste your responses
directly into the STAR database using the online form.
Lesson Title: How Clean is Clean?
Subject: Life Science
Grade Level: 9-12
Author: (Example was adapted from a contribution by Kyla Bradylong)
Lab Site: NASA JPL
Research Presentation Title: Phylogenetic Diversity of Microbial Isolates from the Mars Pathfinder
Lesson Plan Summary (250 Words Max. Please indicate the expected time period of this Lesson Plan):
In this two-session lesson, students will be introduced to microorganisms and to the idea that they can live on surfaces that have
already been “cleaned.” Students will extract and culture microbes from various surfaces and compete to find the “cleanest” surface
in the room and evaluate a cleaning process. Students will use their findings to brainstorm possible cleaning regimens for spacecraft
assembly rooms and spacecraft that should be sterile and how to account for the organisms that survived certain cleaning regimens.
Students will then retest their location after cleaning to determine if they were able to make a difference.
Unique Research Connections
Briefly describe how your lesson plan utilizes your unique insight and/or resources from your research experience.
This lesson plan uses the idea that even when cleaned, surfaces still foster microbial life that can contaminate experiments and
possibly other planets. NASA, through the Planetary Protection Group [1], is concerned with keeping all spacecraft clean and sending
only minimal living organisms into space and to other planets. They test this by sampling various locations on the craft prior to
launch and isolating any life that grows so they know what has been sent and how much has been sent.
[1] http://mars.nasa.gov/msl/mission/technology/insituexploration/planetaryprotection/ (accessed 15 May 2015)
Prior Student Knowledge
What do you expect students to already know before starting this unit?
Familiar with microorganisms, viruses, bacteria, expected lab report format & scoring rubric, experimental safety [2]
[2] Biosafety guidelines link: http://www.asm.org/images/asm_biosafety_guidelines-FINAL.pdf (accessed 20 May 2015)
Students Objectives / Outcomes
Students will know and be able to…
Students will be able to create a supported hypothesis as to the cleanest surface in the room (or school) and make
conclusions based on quantitative evidence and statistical thinking. Students will develop a cleaning process which
connects life science concepts (e.g. cell wall integrity) with specific tests to address a defined problem. Students will
be able to discuss the need to sanitize and clean surfaces, especially those being moved between ecosystems (such as
planets). At the end of the exercise each student will know how to explore an issue, define a problem, propose a
mechanism, design a test, evaluate the evidence, and communicate an argument based on evidence.
NGSS and CCSS STEM Practices
Choose up to three practice(s) that your students will be engaged in during this lesson. Briefly describe how lesson demonstrates the
practice(s):
[X] NGSS - Asking questions (for science) and defining problems (for engineering)
Students design a cleaning process based on mechanisms of cleaner to address a clearly defined problem. What process removes the most
residual microbes (or types)?
[] NGSS - Developing and using models
________________________________________________________________________________________________________________
[] NGSS - Planning and carrying out investigations
________________________________________________________________________________________________________________
[] NGSS - Analyzing and interpreting data
________________________________________________________________________________________________________________
[] NGSS - Using mathematics and computational thinking
________________________________________________________________________________________________________________
[] NGSS - Constructing explanations (for science) and designing solutions (for engineering)
________________________________________________________________________________________________________________
[X] NGSS - Engaging in argument from evidence
Students must consider possible experimental outcomes as supporting or rejecting hypotheses before collecting data and then report actual
findings.
[] NGSS - Obtaining, evaluating, and communicating information
________________________________________________________________________________________________________________
[] CCSS Math - Make sense of problems and persevere in solving them
________________________________________________________________________________________________________________
[X] CCSS Math - Reason abstractly and quantitatively
Students make numerical comparisons of plates rather than subjectively responding to plate appearances.
[] CCSS Math - Construct viable arguments and critique the reasoning of others
________________________________________________________________________________________________________________
[] CCSS Math - Model with mathematics
________________________________________________________________________________________________________________
[] CCSS Math - Use appropriate tools strategically
________________________________________________________________________________________________________________
[] CCSS Math - Attend to precision
________________________________________________________________________________________________________________
[] CCSS Math - Look for and make use of structure
________________________________________________________________________________________________________________
[] CCSS Math - Look for and express regularity in repeated reasoning
________________________________________________________________________________________________________________
[] None of the above
________________________________________________________________________________________________________________
Suggestions for Special adaptations (e.g. ELL, Special Needs, etc.):
- Vocabulary wall
- Hands-on precursor activities to illustrate that microbes feed and grow (e.g. yeast and sugar inflating a balloon with
carbon dioxide), illustrate cell lysing (e.g. filling a balloon with rice ‘plasma’ and bean ‘ribosomes’ and puncturing it
with a ‘cleaner’) , or other.
- Preferential grouping/seating
- Add supporting diagrams for process steps, organisms, and purpose according to your group’s needs
- Develop basic quantitative reasoning by using various methods to represent numbers within the same topic (e.g.
using tables and graphs to examine the same data). Develop higher-order number representation by comparing
decimal and scientific notation when extrapolating results to spacecraft surfaces.
- RODAC plates (which can be directly pressed against a surface) are a time-saving alternative that also reduces the
complexity of the exercise by removing sampling area and swabbing concerns. (Carolina Biological item #823002 or
Fisher Scientific item #08-757-152)
________________________________________________________________________________________________________________
Formative Assessments (How will you evaluate student learning during the unit? Examples include class discussion, free writes,
etc.):
•
Teacher will monitor student understanding by assessing the groups’ discussions about their surfaces and
hypotheses.
•
Teacher will monitor student understanding by monitoring conversations of what makes a surface “clean”
and what can be done to make sure it is cleaner.
•
Consider using a ‘minute paper’ formative tool where students give you a concise answer (Seriously! 1
minute only) to a short answer question you pose at the end of the first and second sessions. The question
should integrate the major concepts of your session. This tool can provide feedback to you and also serve as
intermediate summation of the big ideas. Consider tech alternatives if your class has ‘clicker’ technologies or
one of the free classroom device alternatives (e.g. http://www.socrative.com/ )
________________________________________________________________________________________________________________
Summative Assessments (How will you evaluate student learning at the end of the unit? Examples include: final project, paper,
exam, etc.):
•
•
Teacher will assess student understanding by assessing their formal lab reports according to a rubric based
on class discussion.
Teacher will assess student understanding by judging the cleanliness competition process and outcomes.
Required Common Materials (Rulers, paper products, etc.):
1. Qty 6-10 per group, Q-tips from new package (assumed to be sterile or at least consistently contaminated). Not required if
ordering kit below (includes sterile swabs)
2. Qty 1 pair per student (optional), latex gloves (have a few non-latex pair in case of latex-allergy)
3. Selection of cleaning agents (may include new sponges or wipes, alcohol, soap, detergents, bleach, 3% hydrogen peroxide, heat
lamp/other heat source, UV lamp, etc.)
4. Qty 1 per student or group, Lab notebook
5. Qty 1 per group, Sharpie marker for dish labelling and colony counting
6. Qty 1 per group, small sterile cup of distilled water (if not available, use room temperature water that had been boiling for 1
minute, 3 minutes at altitudes >3,000 ft.)
Required Less Common Materials (Please suggest sources for these items like reagents, sensors, etc. ):
1. Qty 1 per class, 37C Incubator is ideal (e.g. NASCO Item #SB26217N – Lab incubator) though a closed oven or box with a low
wattage light bulb will also work well. Keep drafts out, ensure that temperature doesn’t drop below 20C and doesn’t go above 40C.
2. Qty 3-6 plates per group, Nutrient agar plates (e.g. Carolina Biological Item #821046 – College nutrient agar media kit or Carolina
Item #776366 - Prepared media if you have your own petri dishes)
3. Qty 1 per group (optional), to ensure that groups swab an equivalently sized surface area you may wish to provide disposable
template of an arbitrary size (e.g. 5 x 5 cm)
Pre-Lesson Preparations Guide (Please indicate timing issues or expectations.)
1.
2.
3.
4.
You may wish to pour agar plates in advance (45 min.) or make part of lesson.
It is advisable to try this experiment yourself before bringing to class. Consider sampling different places not accessible to
students for comparison (e.g. dog dish, teacher’s lounge lunch area, etc.).
A typical bleach cleaning solution can be made by diluting Clorox household bleach (64 ml in 1 L of water) to make a 0.525%
sodium hypochlorite solution (5 min.).
Using sterile, disposable petri dishes is recommended. Glass dishes must be autoclaved (20 min. at 121C) to kill bacteria or
soaked overnight in the 0.525% sodium hypochlorite solution.
Step-By-Step Guide (Be Specific / List the Co – Teach Strategies with each step):
Please be specific and efficient, describe how the teacher will capture students’ engagement and hook them on the concept, describe how to conduct the handson/minds-on activities, list higher-order thinking questions which teachers may use to solicit student explanations and help them to justify their explanations, provide
citations if you include others’ work, and indicate the time required for your steps.
1. Warmup (5 min.)
a.
b.
c.
What is the smallest unit of life? (consider viruses, bacteria, archaea, link to unicellular life units)
Where are these found? (consider what are the requirements of life)
What are the roles of microbes in the environment? (consider pathogenic and non-pathogenic
bacteria)
2. Anticipatory set (5 min.)
a.
Have groups consider room ‘clean’ and ‘dirty’ areas. Have groups map the room and choose the
‘cleanest’ area for testing.
b. Groups write a testable hypothesis for study regarding clean areas.
3. Lesson Introduction/Study Design (15 min.)
a. Discuss what ‘clean’ means as a class. What materials are used to make surfaces clean? What are they
cleaning and what do cleaners do? (consider cleaning options including wipe downs, alcohol, soap,
detergents, bleach, hydrogen peroxide, repeated cleaning, heating, multiple cleaners, UV, etc.). May
link mechanisms to cellular destruction or simple removal of requirements of life.
b. Discuss surfaces (consider surfaces which are smooth vs rough, surfaces which can handle being wet,
or heated, or not).
c. Refine hypotheses with cleaning processes.
d. Discuss ways to MEASURE cleanliness (guide toward bacterial cell counts, colony area, or colony
varieties. You may consider using the accepted colony categories [3]
e. Discuss possible outcomes (pictures or examples are helpful). What outcomes would support or reject
proposed hypotheses?
[3] (http://www.microbelibrary.org/component/resource/laboratory-test/3136-colony-morphology-protocol accessed 20 May 2015)
4. Data collection (25 min.)
a.
Groups discuss cleaning procedures to test.
b.
Neatly label plates (e.g. Group 1 Before Cleaning Swab 1, Group 1 After Cleaning Swab 1). Label the
‘agar side’ of the petri dish as the lids can be swapped accidently.
c. Have groups dip the swab in distilled water, swab the same surface area of a surface, and gently
inoculate REPLICATE plates from selected areas. To aid measurements they should all inoculate the
same way (e.g. narrow zig-zags across each plate). Use a fresh swab for each plate – and no double
dipping.
d. Have groups clean the area with their chosen process.
e. Resample the cleaned area with an equal number of replicates (when cleaning products dry).
5. Incubate samples depending upon your setup, 12-48 hours at 37C, 2-7 days at room temperature.
a. Compare plates using one or more of the measurement plans you discussed.
b. NOTE: Caution students to observe colonies, but DO NOT open plates.
6. Data Analysis & Class Discussion (50 min.)
a. Collate data as a class from group measurements (recorded in notebooks). Assess which process
produced the cleanest surface.
b. Consider an assessment of which process produced the best result in comparison to cost, or simplicity,
or least damaging to the surface, etc.
c. Discuss:
i. Why is making things clean important on Earth?
ii. Why would we want to clean spacecraft before launching into space?
iii. What if the microbes from the area need nutrients or conditions different from the nutrient
agar plates? (One of the greatest challenges in modern environmental microbiology.)
iv. What do we know and what do we not know from our study?
7. Homework
a. Groups or individuals complete a formal lab report according to your class format and rubric.
Agar plat inoculation method.
(http://www.asm.org/images/Education/K-12/Putting%20Disinfectants%20to%20the%20Test.pdf accessed 20 May 2015)
Counting colonies using a marker. Counting colony varieties can be done by considering color or
texture differences as bacteria species differences. Colony area can be measured by placing
dishes over graph paper and counting the covered squares (colony-forming units per cm2).
(Image by AndreasReh from http://www.istockphoto.com/photo/bacteria-density-counting-8273602 accessed on 19 May 2015)