Download Activity 2 - Web Adventures

Episode One Debriefing: Teacher Guide
AN IRRITATING PROBLEM
The student will examine how the same medication
(aspirin) has been developed in different ways in
order to counter its most common side effect –
stomach irritation.
Background
Willow bark extract, used at least since the time of Hippocrates, relieves pain
because it contains the chemical salicin. Salicin and other salicylates are useful as
mild pain medications but produce stomach upset as a side effect. The need for a
new drug prompted Felix Hoffman of Friedrich Bayer and Company to develop
acetylsalicylic acid, an analgesic with the pain relieving ability of salicin but with
less stomach irritation. Bayer marketed its new discovery in 1899 under the brand
name Aspirin.
Aspirin proved to be a success with the public, but it too can upset the stomach of
some people. Since 1899, new types of aspirin have been developed which
attempt to solve this problem by altering the interaction of the drug with stomach
acid.
Buffered aspirin contains an antacid to reduce stomach acid and lessen irritation.
However, claims about the effectiveness of this drug are disputed.
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Plaguing Problem
Episode One Debriefing: Teacher Guide
Regular aspirin will dissolve in water, which
has a pH of approximately 7.0. This pH is found
in the mouth.
Regular aspirin or buffered aspirin will
dissolve in acid. An acidic pH is found in the
stomach (pH < 4.0).
Enteric aspirin will dissolve in a base. A
basic pH is found in the intestines (pH >
8.0).
Enteric aspirin is covered by a special coating which allows it to resist stomach acid and
and allows it to dissolve in the small intestine, which has the pH level of a base. Enteric
aspirin doesn’t cause stomach irritation, but the coating slows down the absorption of the
drug.
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Episode One Debriefing: Teacher Guide
Learning Objectives
The student will:
• Discuss the parts of the human digestive tract and their functions.
• Conduct an experiment to determine the solubility of different types of aspirins.
Materials
• Human Digestive Tract Transparency
Per each group of students:
• An Irritating Problem Student Activity Sheets
• safety goggles
• rubber gloves
• aprons
• one enteric (coated) aspirin (use a coated aspirin that is colored such as
Ecotrin® to help distinguish it from the other aspirins)
• one twist tie (used to seal plastic bags)
• one regular aspirin (try to differ the shapes of the regular and buffered or
label with markers)
• one buffered aspirin
• three plastic cups
• one marker
• one piece of cheesecloth
• two graduated cylinders
• 150 ml water
• 100 ml vinegar
• 50 ml bleach
• one watch or timer
Procedure
1. Prior to class, make a transparency of the Human Digestive Tract diagram.
2. State that there is a problem with willow bark extract (salicin). Using the digestive
tract transparency, trace the route of willow bark extract from the mouth to the
stomach. Discuss with students the function of the mouth, saliva, esophagus,
peristalsis, stomach, and gastric juice. Describe how willow bark extract can
interact with stomach acid to produce irritation. Continue the discussion with
information on the small and large intestines and anus.
3. Tell students that aspirin was developed for the people to use instead of willow
bark, but research indicates that it too can irritate the stomach. Discuss the
development of aspirin and the different uses of aspirin.
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Episode One Debriefing: Teacher Guide
4. Hand out the student activity sheet, “An Irritating Problem,” and the diagram of
the human digestive tract. Present Beta's challenge: test the three new types of
aspirin and determine which aspirins dissolve in an acidic environment and
determine which could potentially irritate the stomach.
5. Explain that they will take all three aspirins and dip them into three different
solutions that mimic the environment of the digestive tract. The water will
represent the mouth, the acidic solution will represent the stomach, and the basic
solution will represent the small intestine.
6. Divide the class into groups of two or three students to perform the experiment
described in the student activity sheet, “An Irritating Problem.” Give each group
of students three aspirins to test (aspirins A, B, and C). Each group should get
one enteric (coated) aspirin, one buffered aspirin, and one regular aspirin.
This activity is an adaptation of the Simulated Stomach by David Robson of The
American Chemical Society.
Extension Activities
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Science: Examine the digestive tract of the earthworm.
History: Research the life of Felix Hoffman, the developer of aspirin.
Language Arts: Replace the lyrics of a popular rap, country, jazz, or rock song
with a poem about the parts of the human digestive tract and how they work.
Mathematics: Analyze statistics on the use of aspirin compared to other nonsteroidal anti-inflammatory drugs for a period of time. Create a graph presenting
this information.
Mathematics: Research the development of a new drug and create a pie chart
showing the cost of each phase.
Visual Arts: Create a model of the human digestive tract from common household
items.
Standards
National Science Education Standards, Grades 5-8
• Science Content Standard A: All students should develop abilities necessary to do
science.
• Science Content Standard C: All students should develop understanding of the
structure and function of living systems.
• Science Content Standard F: All students should develop understanding of science
and technology in society.
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Episode One Debriefing: Teacher Guide
Books
•
Graedon, J., Graedon, T., and Ferguson, T. 1993. The Aspirin Handbook: A User's
Guide to the Breakthrough Drug of the '90s. New York: Bantam Books.
•
Gordon, M.A. 1999. Drug Interactions: Protecting Yourself from Dangerous Drug,
Medication, and Food Combinations. New York: Rosen Pub. Group.
•
Hardman, J. G., et al., (Eds.). 1996. Goodman and Gilman's: The Pharmacological
Basis of Therapeutics. (9th ed.). New York: McGraw-Hill.
•
National Research Council. 1996. National Science Education Standards.
Washington, DC: National Academy Press.
Web Sites
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How Stuff Works: Aspirin
http://www.howstuffworks.com/aspirin.htm
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Milestones in Neuroscience Research
http://faculty.washington.edu/chudler/hist.html
•
American Chemical Society (Search for the “Simulated Stomach” Activity)
http://www.chemisty.org
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Useless Information: Aspirin
http://home.nycap.rr.com/useless/aspirin/index.html
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What is the Buffer System in Buffered Aspirin?
http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/buffered-aspirin.shtml
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Episode One Debriefing: Teacher Guide
mouth
esophagus
stomach
sm. intestine
lg. intestine
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Episode One Debriefing: Student Activity Sheet
AN IRRITATING PROBLEM
The student will examine how the same medication
(aspirin) has been developed in different ways in
order to counter its most common side effect –
stomach irritation.
Materials
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two graduated cylinders
rubber gloves
safety goggles
aprons
one twist tie
cheesecloth
three plastic cups
100 ml vinegar
100 ml water
100 ml of a bleach solution (50ml bleach and 50ml water)
Aspirin A
Aspirin B
Aspirin C
one marker
watch or timer
Procedure
1. Before starting, put on safety goggles, rubber gloves, and an apron.
2. Pick one Aspirin A, one Aspirin B, one Aspirin C, and one piece of cheesecloth.
3. Pick 3 cups and label one cup “Neutral”, one cup “Acid”, and one cup “Base”.
4. Using a graduated cylinder, measure 100 ml tap water and pour it into the cup labeled
Neutral.
5. Using a graduate cylinder, measure 100 ml vinegar and pour it into to the cup labeled Acid.
6. Get a new graduated cylinder or clean out the one that was used before. Add to it 50 ml water
and 50 ml bleach. Pour this solution into the cup labeled Base.
7. Line up the cups (in order from left to right): Neutral, Acid, Base.
8. Place Aspirin A, Aspirin B, and Aspirin C in a small square of cheesecloth and twist closed.
Use twist ties to make sure the cheesecloth stays closed. Make sure you are able to tell the
difference between each aspirin. You may want to use a permanent marker to label each
aspirin A, B, and C.
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Plaguing Problem
Episode One Debriefing: Student Activity Sheet
9.
Dip the cheesecloth containing the three aspirins into the cup labeled Neutral – Swirl the
cheesecloth around for 10 minutes.
10. At the end of 10 minutes, record any changes to the aspirins on the “An Irritating Problem”
data sheet.
11. Repeat steps 9 and 10, this time dipping the cheesecloth containing the three aspirin into the
Acid cup.
12. Repeat steps 9 and 10, and this time dipping the cheesecloth containing the three aspirin into
the Base cup.
13. Answer the questions on the data sheet.
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Episode One Debriefing: Student Activity Sheet
Name
Class
Date
An Irritating Problem Data Sheet
Observations In Solutions
Solution in which it
dissolved
(water, acid or base)
Time it took to
dissolve
Other observations
Aspirin A
Aspirin B
Aspirin C
Draw Conclusions
1. Which aspirin is most likely to dissolve in the mouth or stomach? Why?
2. Which aspirin is most likely to dissolve in the small intestine? Why?
3. Which type of aspirin is least likely to irritate the stomach? Why?
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