PAEC Biology Partnership
Lesson Plan #5 “Can I Come In?”
Thomas Brewer, Port St. Joe High School
Sam Ezell, Milton High School
Gabrielle Johnson, Jefferson County Middle School
Todd Kallenbach, Freeport High School
Heidi Montgomery, Franklin County School
Travis Moore, Education Student, Chipola College
Nancy Nwakanma, Lincoln High School
Barbara Rutledge, Gateway Military Academy
Group 9
Lesson Plan #5: “Can I Come In?”
52 minute class period, General High School Biology (adaptable for higher
or lower levels)
MOTIVATION:
Pretest ( see attachment )
Prior to the main activity, students will be given a pretest that will be used to assess their
understanding of osmosis and selectively permeable membranes, as well as to compare
comprehension with a post-test. Students will have 5 minutes to answer the pre-test
questions to the best of their ability. The pre-test may be given directly before the laboratory
activity occurs or during the prior class as pre-lab homework the day before.
As a bellringer, review concepts from previous lectures including osmosis, plasma membrane,
selectively permeable, and cell wall. A possible bellringer could be:
“Choose one object that could be described as selectively permeable.
List one type of matter it is permeable to, and one that cannot pass through.”
The teacher will begin this lesson by asking if any students have observed water being sprayed
on fresh produce at the supermarket. The following picture can be displayed after eliciting
responses from class: http://www.corbisimages.com/images/Corbis-4217156894.jpg?size=67&uid=798dc078-da1e-4ab6-a0fc-a81f8e4af969 (or any suitable picture
will suffice). Ask students to speculate about the characteristics of several vegetable items
before and after being sprayed. Additionally, the teacher can choose to discuss the economic
impact of this practice, in terms of what would happen if the produce was not sprayed
regularly.
The day before the lab, teacher will prepare two 1000 mL beakers; one filled with distilled
water, and the other filled with 10% salt water solution. Freshly cut carrot sticks and celery
sticks (12 each) are placed in each beaker and left overnight.
Teacher will request four student volunteers to come to front and take a carrot stick or a celery
stick from beakers. Students should select one carrot stick and one celery stick from each
beaker (one per student). Have each student, one at a time, hold up their vegetable stick and
attempt to bend it in the middle. Ask other students in the class to explain why some sticks
broke crisply, while others appeared limp and rubbery.
NEEDED MATERIALS:
Teacher prep materials:
*IMPORTANT NOTE: This lab does not require a specific molarity of starch and/or iodine. Two
starch solutions are used of dramatically different concentrations, hence referred to as LOW
and HIGH. If desired, teachers can mix up specific molarity solutions. The results, discussion,
and reflection would be essentially unaltered.
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Three clear containers (approx. a 1 liter each) for holding the standard solutions
below:
-Iodine- Purchase drugstore apothecary iodine tincture (1 oz. is under $4). The
iodine will be greatly diluted to make a standard solution for this lab.
-Corn starch- One large box will provide enough for two separate solutions: one high
concentration and one dramatically lower concentration. As noted earlier, specific
molarity is not necessary.
Distilled water- One gallon jug for mixing solutions
Pre- and Post-Test (including ESOL versions)
student group data sheets
whiteboard (projector, chart paper, etc.) for recording brainstorming ideas
dedicated overnight storage space (counter, tabletop, etc.) for all classes cups
a generic experimental set-up, with different colored water instead of starch/iodine
to serve as a model for student predictions and experimental set-up
two different food coloring dyes, for teacher model (very small amount needed)
Each group of 3-4 students at a lab table should be provided the following materials:
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4 rubber bands
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Four plastic cups numbered 1 through 4 ( 8-12 oz cups for holding solutions
overnight)
8-10 sandwich bags (fold-over style)
Paper towels
Lab data/report sheets for recording/ colored pencils for labeling data pictures
a test tube (or small container) with approximately 5mL of low concentration starch
Solution
a small container of iodine solution with pipette
Classroom:
A large sink should be available for rinsing oil residue from sandwich bags, as well as general
cleanup.
Community Resource:
If a local dialysis nurse is available, this professional may introduce to the class the semipermeable materials used to filter the blood of the dialysis patients. If time restraints don’t
allow a guest to present, the acetate diffusion materials may be presented to the class from the
local dialysis clinic.
OUTCOMES:
Dimensions of K-12 Science Education Standards:
Disciplinary Core Ideas:
1. LS 1:From Molecules to Organisms From Molecules to Organisms: Structures and
Processes
Scientific and Engineering Practices:
1. Planning and carrying out investigations
2. Analyzing and interpreting data
3. Engaging argument from evidence
4. Obtaining, evaluating, and communicating information
Crosscutting Concepts:
1. Systems and system models
2. Energy and matter: Flows, cycles, and conservation
3. Structure and function
4. Stability and Change
Next Generation Sunshine State Standards:
Standard 14: Organization and Development of Living Organisms
SC.912.L.14.2 Relate structure to function for the components of plant and animal cells. Explain
the role of cell membranes as a highly selective barrier (passive and active transport).
(MODERATE)
A. Cells have characteristic structures and functions that make them distinctive.
B. Processes in a cell can be classified broadly as growth, maintenance, reproduction, and
homeostasis.
C. Life can be organized in a functional and structural hierarchy ranging from cells to the
biosphere.
D. Most multicellular organisms are composed of organ systems whose structures reflect their
particular function.
SC.912.N.3.5 Describe the function of models in science, and identify the wide range of models
used in science. (MODERATE)
Content Literacy Standards:
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Integration of Knowledge and Ideas
Research to Build and Present Knowledge
Comprehension and Collaboration
Conventions of Standard English
SPECIFIC LEARNING OUTCOMES:
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After analyzing various solutions, the students will be able to explain, with at least 80 %
accuracy, how molecules in a solution are able to move from an area of high
concentration to an area of low concentration, as well as predict examples of diffusion
direction from given situations. Post-Test is used for this data.
Using the data collected from the activity, students must be able to infer correctly, with
at least 80% accuracy, what will happen to different cells (baggies) as they interact with
different solutions of concentration. Reflection questions and/or Post-Test can be used
for this data.
PRESENTATION & PARTICIPATION:
BEHAVIOR - lecture: The teacher will begin the lesson by introducing/reviewing a few details
about the processes students will be experiencing. Teachers will tell students that in this lab
they will be observing the passage of a substance across a semi permeable membrane.
Teachers should remind students that substances want to travel from an area of high
concentration to lower concentration.
COGNITIVE – brainstorming / conversations: Additionally, the teacher will introduce, if not
taught previously in the class, the concept of an indicator. The teacher should ask the class to
complete PART ONE of the data sheet (what the word INDICATE means, as well as examples of
items that are used to indicate some sort of change). Student responses can be written on the
board, simply shared orally, after being written by the students on their lab sheets.
APPLICATION/PROCESS – inquiry based: Pass out student group data sheets. Here is where
students will complete PART TWO To both observe an indicator at work AND to see what
change their experiment will produce, students will observe how iodine indicates presence of
starch.
1. Students will receive a test tube with approximately 5ml of the low concentration starch
solution per group.
2. A student will add three drops of iodine solution.
3. Students will describe any changes observed on their lab sheet. Lab sheet is attached.
APPLICATION / PROCESS – testing hypothesis: Now that students have both seen an indicator
at work AND seen what to expect in their own results, it is time to move onto the bulk of the
activity.
The teacher will hold up their model and ask students to predict what would happen to the
colors of water in the bag if left undisturbed overnight. Predictions are written on the student
group data sheet.
Student groups will receive their lab materials:
-4 containers (plastic cups are best)
-plastic bags
-access to solutions (a dedicated lab manager/materials person is recommended for
retrieving and returning supplies)
-rubber bands
-direction sheet
Students are instructed to read the entire sheet prior to beginning their predictions. When
instructions have been read, student groups are to formulate hypotheses for the four different
cups. Predictions (and justifications) are written in the correct section of the data sheet. Data
sheet is appended.
Student Directions:
In this lab, students will observe the diffusion of a substance across a semi permeable
membrane. The plastic bags, like all man-made plastics, are covered with microscopic pores.
These pores model the permeability of a cell’s plasma membrane. You will be setting up four
experimental containers.
These containers will represent four different
situations. The picture below illustrates what
the set-up should entail, but students MUST read
the directions prior to setting up your experiment:
This is where the teacher will create their model in front of the class. It will serve as both a
model for student experimental design, but as the object that students will use for predictions.
Pour 50mL of food colored water into the cup. Pour 50mL of a different colored water into the
bag. Suspend the bag in the cup, securing the edge with a rubber band. It is now a complete
model. Direct students to question 3 and 4 of part two of the data sheet. Ask students to
predict what they would see if the bag was to sit undisturbed overnight. Challenge them to
justify their answers.
APPLICATION / PROCESS – testing hypothesis:
Now it is time for students to set-up their own experiments.
Please note: ALL four cups will be set up the same general way, with the locations of the
different solutions and different concentrations being changed between cups.
These procedures are written on the student group data sheets, so please refer students to
them throughout the set-up. Additionally, the teacher should require that procedure directions
should be read completely, at least once, before materials are distributed.
Procedure:
1. Set the four cups near the middle of the table.
2. Pour the following material into the correct cup:
a. In cup #1 pour 50mL of the iodine solution.
b. In cup #2 pour 50mL of the iodine solution.
c. In cup #3 pour 50mL of the LOW concentration starch solution.
d. In cup #4 pour 50mL of the HIGH concentration starch solution.
3. You will now put liquid into the bags, suspend the bags in the liquid of the cup, and
secure the edge with a rubber band. There is an example set-up in the front of the
room:
a. Cup #1 bag will receive 50 mL of LOW concentration starch.
b. Cup #2 bag will receive 50mL of HIGH concentration starch.
c. Cup #3 bag will receive 50mL of iodine solution.
d. Cup #4 bag will receive 50 mL of iodine solution.
4. Wait fifteen minutes and record your observations in the data table below.
5. Set your cups in the designated area and return to your tables to work on conclusion
questions.
QUESTIONING:
1. What is the role or function of the plastic bag in the experiment?
2. Which molecules (H2O, starch, and/or iodine) were able to diffuse through the plastic bag?
Justify your answer.
3. Describe how the concentration of the starch solution produced different results in the
experiment?
4. At the end of the experiment, did any of the bags gain water as well as other matter? Justify
your answer.
5. Justify the following statement with at least two specific details from the experiment:
The plastic baggie is selectively permeable.
REFLECTION & REVIEW:
The students will be given a post test. The post-test will be the same as the pre-test and is
simply relabeled “post-test”. The post-test is attached. The teacher will grade the pre and post
tests and hand them back at the beginning of the next class. The teacher will also go over the
post tests with the class, addressing any commonly missed questions.
For homework, students can be given a short reinforcement assignment. This can also help
serve to identify common misconceptions that the teacher can use to decide the appropriate
amount of remediation, either on an individual basis or on the whole class level.
Additionally, the students will be given this question the following class as a bellringer:
Explain how the plastic bag represents a semi-permeable membrane?
Below is a suggested rubric for helping the teacher decide on the appropriate amount of
remediation. It serves both as a diagnostic and a review.
Grading Rubric:
0- No understanding of how the plastic bag represents a semi-permeable membrane.
1- Minimum understanding the students mentions that certain things can move across, but
with no detail.
2- Some understanding the students can explain with some detail what is taking place between
the solution and plastic bag solution.
3- Understands that iodine and water can move across the membrane but the starch cannot.
The student also explains how they know this is taking place.
SAFETY:
There is a posted chart of general lab safety guidelines on the wall of the classroom. The
teacher should make a point to review the general safety practices and the safety related to the
lab.
Teacher should point out the location of the standard iodine and cornstarch solutions on the
materials table, as well as provide paper towels or absorbent towel to wipe up spills.
Safety precautions:
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Be sure there is adequate walk space between lab tables.
Goggles should be worn while working with the iodine solution.
Students should be instructed not to taste the solutions.
Spills should be immediately wiped up to prevent slippage.
TRANSFORMATIVE:
There are 3 special needs students in this classroom: One student has a mobility impairment,
another an attention deficit condition, and the last student is an ESOL student.
Mobility Impairment: Make sure that the lab site is wheelchair-accessible, uncluttered, clear,
wide aisles and adjustable-height work surface.
Attention Deficit: Make sure that this student would have preferential seating to avoid
distractions and minimize extraneous stimuli, repeated demonstration of procedure and
support practice, and combination of written, verbal, and pictorial instructions.
ESOL Students: Make sure that you allow for extended time, use visuals, and rewrite portions
of the lesson to make them more comprehensible. (ESOL version of pre- and post-tests, as well
as data sheets are appended to this document).
UTILIZE:
1. The Pre-Test/Post-Test Challenge. Comparison of Pre-Test and Post-Test will be the first
area of concern. If students do not show measurable improvement, then there may be one or
more problems with the Lesson Plan:
a. Pre-Test and Post-Test may not fit the activity closely. If so, we can revise them to
more closely match the lessons learned in the activity.
b. The activity may fail to demonstrate the concepts explored in the Pre-/Post-Test in a
way that the students can comprehend, if so, we may need to adjust the activity (or the
Teacher’s narrative regarding the activity) until the concepts are more clearly represented.
c. The higher order questions may not challenge the students to effectively grapple with
the information to achieve a deeper understanding of the content. If this is the case, we will
need to work to ask more rigorous questions and guide the students to better understand the
content.
2. The Standards Challenge. We will need to assess the clarity of the coverage of our selected
standards. We will need to ask the following questions and make the necessary adjustments:
a. Do the pre- and post-tests conform well to our standards, and does a good
performance on the pre- and post-tests correlate to mastery of the standards by our students?
This would be measured in the longer term (such as a chapter or unit test)? If the pre- or posttests are found to be inconsistent with our standards, we would need to make adjustments to
the questions to more closely align with the selected standards.
b. Does the activity properly direct students to a deeper mastery of the selected
standards?
c. Do the higher order questions direct students to a deeper understanding of the
standards? If the higher order questions do not aid in the students’ understanding of the
selected standards, we need to edit or rewrite them to fit the standards better.
3. The Time Challenge. From pre-test to post-test and with the motivation piece, there are
several components in this activity. The sum total of these components may take longer than
the allotted time. Included in our plan is the flexibility to move the first component to the
previous day and the last component to the following day. Also every teacher (along with his or
her students and his or her school) creates a unique culture that moves at its own pace. We
must be flexible to adapt this plan to each individual classroom’s culture.
4. The Facilities Challenge. While we can anticipate that the most teachers can quickly fit the
activity to their own space or facilities limitations, there may be spaces that require more
changes to the activity. All teachers will need to prepare space accordingly for their particular
situation. The provided room setting is flexible without impacting the lesson in a negative way.
5. Lesson Strengths: This lesson encourages higher level thinking as described in Bloom’s
taxonomy. It is a brief lab but does an excellent job of helping students visualize the aspects of
diffusion. Results are essentially guaranteed. Materials are inexpensive and readily available
locally. Safety is a minimal concern.