Egg Osmosis
Megan Hollingsworth
Fox Tech High School
San Antonio, Texas
Summer 2004
Research Host:
Dr. John M. Johnson
University of Texas Health Science Center
Lesson # 11
Appropriate citation:
Hollingsworth, M. Egg Osmosis (APS Archive of Teaching Resources Item #8680).
[Online]. Bethesda, MD: American Physiological Society, 2004.
http://www.apsXarchive.org/resource.cfm?submissionID=8680.
Editor’s notes:
Website URLs listed in this resource were current as of publication, but may now be
obsolete. If you know of a replacement URL, please suggest it in the resource’s
“Comments” section.
Disclaimer:
This activity was created by the author and reviewed by the American Physiological
Society. Any interpretations, statements, or conclusions in this publication are those
of the author and do not necessarily represent the views of either the American
Physiological Society or the funding agencies supporting the professional development
program in which the author participated.
Frontiers in Physiology
www.frontiersinphys.org
© The American Physiological Society
Permission is granted for workshop/classroom use with appropriate citation
Egg Osmosis
Teacher Section
To determine the effects of various liquids on a model of the cell membrane.
Students will be able to:
Work cooperatively in a group setting.
Successfully navigate the Internet to find answers.
Develop a working definition of osmosis, diffusion, hypertonic,
hypotonic and isotonic.
Design a lab procedure to test a hypothesis.
Collect and analyze data.
Create a poster or other multimedia presentation and share it with an
appropriate audience.
Thoughtfully critique a peer's poster/presentation.
This activity is geared for 9th - 10th grade students.
K-12 Unifying Concepts & Processes:
Grades 9-12:
Evidence, models, and explanation
Change, constancy, and measurement
Science as Inquiry:
Abilities necessary to do scientific inquiry
Understandings about scientific inquiry
Physical Science:
Structure and properties of matter
Life Science:
The cell
Texas Essential Knowledge and Skills: Biology
1A: Demonstrate safe practices during field and laboratory investigations
2A-D: The student uses scientific methods during field and laboratory investigations by
planning and implementing investigative procedures including asking questions, formulating
testable hypotheses, and selecting equipment and technology; collecting data and making
measurements with precision; organizing, analyzing, evaluating, inferring and predicting trends
from data; communicating valid conclusions.
3A: Analyzing, reviewing, and critiquing scientific explanations, including hypotheses and
theories, as to their strengths and weaknesses using scientific evidence and information.
3E: Evaluate models according to their adequacy in representing biological objects or events.
4A: Identify the parts of eukaryotic cells
4B: Investigate and identify cellular processes including homeostasis, permeability, and
function of cellular parts.
11A: Identify and describe the relationships between internal feedback mechanisms in the
maintenance of homeostasis.
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
Teacher Section
This lab activity takes five-seven days to complete.
Students should be somewhat familiar with the structure of a cell and that the
cell membrane is semi-permeable. Students should also have some background
in scientific methods and the importance of a control group. Students should
have skills in using a balance, ruler, graduated cylinder, beakers, etc.
This activity allows for auditory, visual, and tactile learners to participate and
understand fully. Auditory learners gain from the presentations and group
discussions. Visual learners gain from the web quest and poster session.
Tactile learners gain from the experimentation and enjoy the daily
measurement of the eggs. Groups should be heterogeneous and students should
alternate tasks daily. Be sure not to allow the females to only be recorders or
poster-makers. Everybody in a group should be encouraged (and required) to
get their "hands dirty."
Use care when handling raw eggs as they may contain Salmonella. Be sure
students always wash hands thoroughly after handling eggs. The solutions the
students choose will likely not be harmful, but always follow standard safety
precautions when handling any chemicals. Goggles and aprons may be worn to
prevent splashes from harming eyes and clothing.
What about using different concentrations of the liquids rather than
different liquids?
How do thicker solutions affect the egg compared to thinner solutions? Is
it just a matter of "thickness?"
Can you stretch an egg, shrink it, and then stretch it even more?
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
Teacher Section
Copies of KWL handout
Internet Access & Copies of Internet Treasure Hunt
Raw Eggs
Fresh orange
Vinegar
Distilled water
Various solutes, solvents, and solutions (salt, sugar, oil, syrup, milk, soda,
and sports drinks, for example)
Paper towels
Food coloring
String
Standard lab equipment (balances, rulers, tongs, beakers, graduated
cylinders)
Raw potato
Knife
Spray water bottle
Slice at least 3 equal sized pieces of raw potato. Place one piece in each
of the following solutions: tap water, distilled water, and salt water. Allow
students to observe for a few days before you begin with the egg
experiments.
Raw eggs should be de-shelled with vinegar 24-48 hours before
experiments. I suggest using 400mL beakers with enough vinegar to cover
the egg with 250mL beakers placed on top (gently) to keep egg submerged
to allow for even shell dissolving. If the teacher prefers, he/she could
allow the students to help with this step to incorporate some chemistry
(chemical changes) into the lesson.
The entire activity will take 5-7 days, depending on the solutions your
students choose to test and if you allow for students to revise their
protocols and retest.
Teachers will also need to arrange to use a computer lab to research the
Treasure Hunt questions. It is a good idea to look over the websites prior
to taking the class. It is ideal to have one computer per student, but two
students to a computer will also be sufficient.
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
Teacher Section
Day 1: Engage
Demonstrate diffusion by peeling an orange at the front of the room. Have
students put their thumbs up when they smell the orange in their part of the
room. Why does this happen? (It moves from an area of high concentration to
an area of low concentration.)
Discuss what they know about movement of particles/water by completing the
K of the KWL chart.
Explore
Use a pre-set up demonstration of the raw potato pieces in distilled water, tap
water, and salt water to stimulate questions about how different solutions
affect cells. Complete the W of the KWL chart.
Day 2: Explain
Internet Treasure Hunt (Handouts in Student Section)
Pair students by ability levels (high level with low level) if there are not
enough computers for the whole class. If you only have one 45-60 minute
class period for internet research, you may want to assign specific questions
or websites to the students. If you could add in an extra day for research,
groups should be able to look over all websites and answer all questions.
This day can also be used to refine the W section of the KWL. Student should
generate more knowledge as well as curiosity that can be applied to the KWL.
Day 3-4: Elaborate
Students should test the question, "What effect do various liquids have on a
model of the cell membrane?" Student groups form a hypothesis about what
will happen to the eggs, write a detailed protocol, get approval from the
teacher and perform the experiment. Teachers should step away from
controlling the students as much as possible. It is during this experimentation
time that the students will be working independently. Teachers should only
serve as a resource and a facilitator. Encourage students to compare different
liquids, different concentrations of the same liquid, etc. Be sure students have
a plan for measurement and set a schedule for different members to come by
the classroom to measure eggs before school, after school, at lunch, etc.
More measurements allow for better data analyses.
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
Teacher Section
Day 3-4: Elaborate, contd.
*Teachers only: A sample plan would be to compare two eggs: one in tap water
and one in syrup. Over 2-3 days, students would check the size/volume of the
egg a few times a day. You do not need to share this information with the
students, but use it to guide them while checking their ideas.*
Data is collected in a chart and students compare results. The methods for
gathering data are very important in this lab, as most students will realize:
Do we dry the egg before measuring? How do I handle the egg and measure it
without harming it and destroying my data? What if I measure differently
than my lab group? How are volume and mass related?
Day 5-7: Evaluate
Students generate a rubric for presentation/poster expectations (see sample
rubric in the Student Section). Students create posters/Power Point
presentations and present to the class. Teacher should guide discussions with
the class about individual groups' scientific methods and help students see if
comparisons can be made between groups.
Teacher should guide a class discussion to complete L of the KWL chart upon
completion of all presentations.
Oral group presentations
Poster or Power Point presentations
Student-generated rubrics and student-graded presentations (they grade
each other with the rubrics)
Journaling daily to track experiment progress
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
Teacher Section
Investigate the cell membrane more thoroughly through web quests.
Discuss permeability and the advantages and disadvantages for cells.
Describe the differences between hydrophilic and hydrophobic and why
the bilayer is important in the cell membrane.
Guest speakers such as transport mechanism physiologists could come give
a presentation and discuss methods of membrane transport other than
osmosis.
Barbara E. Goodman, Ph.D. "Cell-ebration: How Cells Work"
(http://www.usd.edu/~bgoodman/cell-ebration.html)
"Rubistar" (http://rubistar.4teachers.org/index.php)
"Osmosis" (http://arbl.cvmbs.colostate.edu/hbooks/cmb/cells/pmemb/
osmosis.html)
"Osmosis" (http://physioweb.med.uvm.edu/bodyfluids/osmosis.htm)
"Homeostasis and Transport"
(http://www.sirinet.net/~jgjohnso/homeostasis.html)
"Virtual Cell" (http://www.life.uiuc.edu/cgi-bin/plantbio/cell/cell.cgi)
"Diffusion, Osmosis, and Cell Membranes"
(http://biology.arizona.edu/sciconn/lessons/mccandless/reading.html)
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
Student Section
This info search will help you find information about osmosis. You will be looking
at pre-selected web sites to answer questions.
Review each web site for information and consider who wrote the site, what their
purpose is in writing it, and the credibility (accuracy) of the information.
Why is osmosis important to a cell?
Web Site
URL
Site 1:
Site 2:
http://arbl.cvmbs.colostate.edu/
http://physioweb.med.uvm.edu/
hbooks/cmb/cells/pmemb/osmosis.html
bodyfluids/osmosis.htm
Who created
this web site ?
Why did they
create it?
(check all that
apply)
†
†
†
†
To provide factual information
To influence the reader’s opinion
To sell a product or service
I’m not sure
†
†
†
†
To provide factual inform ation
To influence the reader’s opinion
To sell a product or service
I’m not sure
How credible
(accurate) do
you think the
info is?
†
†
†
†
Very accurate
Somewhat accurate
Not very accurate
I’m not sure
†
†
†
†
Very accurate
Somewhat accurate
Not very accurate
I’m not sure
What did you
learn?
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
Student Section
This info search will help you find information about hypertonic and hypotonic
solutions. You will be looking at pre-selected web sites to answer questions.
Review each web site for information and consider who wrote the site, what
their purpose is in writing it, and the credibility (accuracy) of the information.
How are hypertonic solutions and hypotonic solutions related?
For Site 2, go to the "Osmosis" section and
stop after #24. Be sure to look at table 5.1.
Web Site
URL
Site 1:
http://arbl.cvmbs.colostate.edu/
hbooks/cmb/cells/pmemb/osmosis.html
Site 2:
http://www.sirinet.net/~jgjohnso
/homeostasis.html
Who created
this web site ?
Why did they
create it?
(check all that
apply)
†
†
†
†
To provide factual information
To influence the reader’s opinion
To sell a product or service
I’m not sure
†
†
†
†
To provide factual inform ation
To influence the reader’s opinion
To sell a product or service
I’m not sure
How credible
(accurate) do
you think the
info is?
†
†
†
†
Very accurate
Somewhat accurate
Not very accurate
I’m not sure
†
†
†
†
Very accurate
Somewhat accurate
Not very accurate
I’m not sure
What did you
learn?
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
Student Section
This info search will help you find information about cell membrane regulation.
You will be looking at pre-selected web sites to answer questions.
Review each web site for information and consider who wrote the site, what
their purpose is in writing it, and the credibility (accuracy) of the information.
How does a cell membrane regulate its contents, that is, what moves into
and out of the cell?
For Site 1, click "cut" to see plasma membrane,
then "zoom" to get closer. Click "write" for details.
Web Site
URL
Site 1:
http://www.life.uiuc.edu/cgibin/plantbio/cell/cell.cgi
For Site 2, go to section "How Cells Deal
with Osmosis" and read down from there.
Site 2:
http://www.sirinet.net/
~jgjohnso/homeostasis.html
Who created
this web site ?
Why did they
create it?
(check all that
apply)
†
†
†
†
To provide factual information
To influence the reader’s opinion
To sell a product or service
I’m not sure
†
†
†
†
To provide factual inform ation
To influence the reader’s opinion
To sell a product or service
I’m not sure
How credible
(accurate) do
you think the
info is?
†
†
†
†
Very accurate
Somewhat accurate
Not very accurate
I’m not sure
†
†
†
†
Very accurate
Somewhat accurate
Not very accurate
I’m not sure
What did you
learn?
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
Student Section
This info search will help you find information about homeostais and osmosis.
You will be looking at pre-selected web sites to answer questions.
Review each web site for information and consider who wrote the site, what
their purpose is in writing it, and the credibility (accuracy) of the information.
What happens when homeostasis is not being maintained by osmosis?
Web Site
URL
Site 1:
http://physioweb.med.uvm.edu/
bodyfluids/osmosis.htm
Site 2:
http://biology.arizona.edu/sciconn/
lessons/mccandless/reading.html
Who created
this web site ?
Why did they
create it?
(check all that
apply)
†
†
†
†
To provide factual information
To influence the reader’s opinion
To sell a product or service
I’m not sure
†
†
†
†
To provide factual inform ation
To influence the reader’s opinion
To sell a product or service
I’m not sure
How credible
(accurate) do
you think the
info is?
†
†
†
†
Very accurate
Somewhat accurate
Not very accurate
I’m not sure
†
†
†
†
Very accurate
Somewhat accurate
Not very accurate
I’m not sure
What did you
learn?
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
water transport through
membranes.
What I Learned about
What I Know about
water transport through
membranes.
Name:
water transport through
membranes.
What I Want to know about
Period:
Student Section
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
Student Section
Teacher Name:
Student Name:
CATEGORY
4
3
2
1
Idea
Independently
identified a question
which was interesting
to the student and
could be investigated.
Identified, with adult
help, a question which
was interesting to the
student and which
could be investigated.
Identified, with
adult help, a question
which could be
investigated.
Identified a question
that could not be
tested/investigated or
one that did not merit
investigation.
Hypothesis
Development
Independently
developed an
hypothesis well substantiated by a
literature review and
observation of similar
phenomena.
Procedures were
outlined in a step -bystep fashion that could
be followed by anyone
without additional
explanations. No adult
help was needed to
accomplish this.
Independently
developed an
hypothesis somewhat
substantiated by a
literature review and
observation of similar
phenomena.
Procedures were
outlined in a step -bystep fashion that could
be followed by anyone
without additional
explanations. Some
adult help was needed
to accomplish this.
Independently
developed an
hypothesis somewhat
substantiated by a
literature review or
observation of similar
phenomena.
Procedures were
outlined in a step -bystep fashion, but had
1 or 2 gaps that
require explanation
even after adult
feedback had been
given.
Needed adult
assistance to develop
an hypothesis or to do
a basic literature
review.
With adult help,
identified and clearly
defined which
variables
were going to be
changed (independent
variables) and which
were going to be
measured (dependent
variables).
Adult help needed to
identify and define
almost all the
variables.
Each element had a
function and clearly
served to illustrate
some aspect of the
experiment. Most
items, 6, graphs etc.
were correctly labeled.
The display seemed
incomplete or chaotic
with no clear plan.
Many labels were
missing or incorrect.
Student provided a
conclusion with some
reference to the data
and the hypothesis
statement(s).
No conclusion was
apparent OR
important details were
overlooked.
Description of
Procedure
Variables
Display
Conclusion/
Summary
Independently
identified and clearly
defined which
variables were going
to be changed
(independent
variables) and which
were going to be
measured (dependent
variables).
Independently
identified which
variables were going
to be changed
(independent) and
which wer e going to
be measured
(dependent). Some
feedback was needed
to clearly define the
variables.
Each element in the
Each element had a
display had a function function and clearly
and clearly served to served to illustrate
illustrate some aspect some aspect of the
of the experiment. All experiment. Most
items, 6, graphs etc. items, 6, graphs etc.
were neatly and
were neatly and
correctly labeled.
correctly labeled.
Student provided a
Student provided a
detailed conclusion
somewhat detailed
clearly based on the
conclusion clearly
data and related to
based on the data and
previous resear ch
related to the
findings & hypothesis hypothesis
statement(s).
statement(s).
Megan Hollingsworth
Egg Osmosis
©2005 The American Physiological Society.
Procedures that were
outlined were
seriously incomplete
or not sequential,
even after adult
feedback had been
given.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
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