Diffusion or Not?
Suzanne Goedeken
Silver Lake High School
Roseland, Nebraska
Summer 2004
Research Host:
Dr. Janet E. Steele
University of Nebraska-Kearney
Lesson # 7
R#8570
Appropriate citation:
Goedeken, S. Diffusion or Not? (APS Archive of Teaching Resources Item #8570).
[Online]. Bethesda, MD: American Physiological Society, 2004.
http://www.apsXarchive.org/resource.cfm?submissionID=8570.
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
Diffusion or Not?
Teacher Section
To understand the principles behind diffusion and osmosis.
Upon completion of this activity, students will be able to:
Understand the mechanisms behind diffusion.
Develop an inquiry lab to explain diffusion.
Create a poster to be displayed in a poster session communicating the
results of the experiment in a manner that is appropriate for the
audience.
Describe where in the body diffusion occurs.
This lab was designed for high school students and could be adapted for junior
high classes if the fourth objective is left out.
Grades 9-12
Science as Inquiry:
Abilities necessary to do scientific inquiry
Understandings about scientific inquiry
Life Science:
The cell
Matter, energy, and organization in living systems
This lab will take two days in block schedule and three-four days in a regular
schedule.
This lab should fall during a unit on cells.
Suzanne Goedeken
Diffusion or Not?
©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
Individuals from different professions could come in and speak to the class
about how and where diffusion is used in their profession (For example, the
medical profession and the human body, agriculture and plant growth). This
activity addresses different learning styles with visual and hands-on activities.
Make sure that students are familiar with the equipment that will be used.
If need be, review how to use the equipment.
Students should demonstrate and abide by all regular safety policies
established in the classroom.
The chemicals in this lab need to used with some caution as with any
chemicals. Goggles should be worn. If a student gets some on the hands,
he/she should wash them promptly.
Were the weights of the bags the same at the beginning and the end of the
experiment? Why or why not?
What could be occurring with the glucose/starch solution?
Why did we use a color solution inside the bag?
Is the digital camera helpful? Why?
Suzanne Goedeken
Diffusion or Not?
©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
For each lab group (2-3 students):
Dialysis tubing (8”-12” soaked in water overnight)
String for tubing
Balance
2 12 oz. clear plastic cups
Sharpie pen/permanent marker
1 funnel
15 ml Glucose/starch solution*
100 ml distilled water
5 ml IKI solution
1 Glucose TesTape**
1.0 Molar sucrose solution
Graphing calculator/computer
For the class:
Digital camera
Lugol's solution**
1 Tape measure
5 drops peppermint extract
Benedicts solution**
1 Orange
4 Stopwatches
1 Balloon
* You can make this instead of purchasing it. Dissolve 10 g of soluble starch in 1 liter of water.
Add 150 g of glucose.
** If you do not have TesTape: Two-three drops of Lugol's Solution turns brown in the presence
of starch and two-three drops of Benedicts Solution turns blue in the presence of glucose.
Anticipatory Activity:
1. Mark off 1 meter, 2 meters, and 3 meters.
2. Place students at each mark. Each group will be given a stop watch.
3. Students close their eyes while the teacher stands at 0 meters and peels an
orange. As the orange is peeled, each group begins their stop watch.
4. When each group smells the orange they stop their stopwatch.
5. The data from each group is then placed in a table on the board.
6. Each student will graph the data.
Adapted from "My Health, My World: My World Indoors, There’s Something in the AIr"
Or
1.
2.
3.
you can do a similar activity with peppermint oil placed inside of a balloon.
Place 3-5 drops of peppermint oil inside of a balloon.
Blow up the balloon and tie the end.
Time how long it take the smell to permeate the 1 meter, 2 meter and 3
meter marks.
Suzanne Goedeken
Diffusion or Not?
©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
Part 1: Diffusion Analysis
1. Place students in groups of 2-3. Have each group fill a plastic cup 2/3 full
of distilled water, and add a 5 mls of IKI solution to the cup. Test the
contents with TesTape (or alternate solutions).
2. Tie of one end of piece of dialysis tubing in a knot. Rub the other end
between the fingers to open it up. Do this only when ready to fill it.
3. Place the funnel into the open end of the tubing and pour 10-15 ml of
glucose/starch solution into the tube. Repeat the "tying-off" procedure on
the open end. Test a small sample of the glucose/starch solution with
TesTape to see the results. Rinse off and blot dry.
4. Place an empty, dry plastic cup on the electronic balance, tare the balance
EACH TIME, blot of the outside of the bag and weigh. Record the initial
mass.
5. Place the dialysis bag into the plastic cup and let it stand for 15 - 20
minutes.
6. Measure the final weight of the bag.
7. Test the liquids in the beaker and in the bag with TesTape.
8. Have students chart (paper, computer or graphing calculator) the initial
observation, then have them explain (orally or in writing) what happened in
this part of the activity. You may want to perform this activity again and
switch the location of the solutions. In this case take into account how
much of each solution you will need.
Extended exploration:
You can add 2-3 drops of food coloring to the solution in the dialysis tubing.
Use a digital camera and take images as the process occurs. Take an image
at the beginning of the process, every minute until the process is complete.
You can try Part 1 with different concentrations of sucrose solution as well.
Suggested concentrations are 0.2 molar, 0.4 molar, 0.6 molar, 0.8 molar and
1.0 molar. Have the class compare results.
You can also try to Part I with different fruits/vegetable/meat products.
You only need a sample the size of a cork for this experiment. It would be
interesting to mix the sample types with different concentrations.
Suzanne Goedeken
Diffusion or Not?
©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
Part 2
1. Complete an Internet Info Search to find information on osmosis.
2. Start a KWL, at this point answering only the “K” & “W.”
3. Using their questions in the “W” section (what you want to know), students
come up with one question they would like to answer. Examples of possible
student questions include:
How does osmosis occur? Where does osmosis occur? Why does osmosis
occur?
4. Students then develop a hypothesis and design an experiment that will
answer their question with the equipment provided.
5. Students create a poster or Power Point presentation to explain their
experiment and results.
6. As a class, return to the KWL to fill in "L" section (what I learned) and
check for understanding.
Part 2 can be integrated into an Anatomy & Physiology class. This can
be used to fulfill Objective 4.
A "real world" application of this would be dialysis. A professional that
deals with dialysis could come in and discuss this process with the
students.
Have students research other examples of osmosis in the body. A question
to think about "Why do we have wrinkled skin when we get out of the
swimming pool?"
Suzanne Goedeken
Diffusion or Not?
©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
Part 1:
Each group will be required to fill out the Student Data Sheet. After each
group has completed its Data Sheet, the class will collectively prepare
one poster, which includes all steps of the scientific method.
Part 2:
Each group will produce a poster showing the steps and results of its
experiment. It should follow the grading rubric and include all parts. This
poster will be presented to the other groups.
"Diffusion & Osmosis with Data Analysis"
(http://accessexcellence.org/AE/AEC/AEF/1995/lukens_analysis.html)
Moreno, N. et al. "My Health My World: My World Indoors". (1997). Baylor
College of Medicine.
Preview materials at http://www.carolina.com/baylor/
Suzanne Goedeken
Diffusion or Not?
©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.
As you review each site, consider who wrote the site and how credible
(accurate) you think the information is.
Web site #1
http://www.purchon.com/biology/osmosis.htm
Describe how osmosis occurs.
Web site #2
http://www.vivo.colostate.edu/hbooks/cmb/cells/pmemb/osmosis.html
Explain the difference between isotonic, hypertonic, and hypertonic. Explain
one place in the human body where osmosis occurs.
Web site #3
http://www.web.ukonline.co.uk/webwise/spinneret/life/osmdia.htm
Describe how osmosis is an example of active transport. Describe how and
why osmosis occurs in plant cells.
Suzanne Goedeken
Diffusion or Not?
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
What I Learned about
osmosis.
What I Want to know about
osmosis.
What is osmosis? Why does it occur in living organisms?
What I Know about
osmosis.
Name:
Period:
Student Section
Suzanne Goedeken
Diffusion or Not?
©2005 The American Physiological Society.
2004 Frontiers in Physiology Research Teacher
Works in Progress
Permission is granted for duplication for workshop/classroom use.
This page is intentionally left blank.