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Hands-on Activity: Protect That Pill
Contributed by: Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

Close-up photo shows a pile of pills.
Pills come in a variety of shapes, colors, sizes and textures.


Students reinforce their knowledge of the different parts of the digestive system and explore the concept of simulation by developing a pill coating that can withstand the churning actions and acidic environment found in the stomach. Teams test the coating durability by using a clear soda to simulate stomach acid.

Engineering Connection

Relating science and/or math concept(s) to engineering

Surprisingly, much design goes in to developing pill tablet coatings and the systems that apply these coatings. Varying the material or thickness of a coating can dramatically affect a medication's effect on the body. Engineers play an integral role in this process, from developing and testing chemicals for coatings to designing the complex systems used to mass produce uniformly-coated pills.


  1. Pre-Req Knowledge
  2. Learning Objectives
  3. Materials
  4. Introduction/Motivation
  5. Vocabulary
  6. Procedure
  7. Attachments
  8. Safety Issues
  9. Troubleshooting Tips
  10. Assessment
  11. Extensions
  12. Activity Scaling
  13. Multimedia
  14. References

Grade Level: 7 (6-8) Group Size: 3
Time Required: 50 minutes
Activity Dependency :None
Expendable Cost Per Group
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Related Curriculum :

Educational Standards :    

  •   Colorado: Math
  •   Colorado: Science
  •   Common Core State Standards for Mathematics: Math
  •   International Technology and Engineering Educators Association: Technology
  •   Next Generation Science Standards: Science
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Related Standards for Common Core State Standards for Mathematics

  •      Common Core State Standards for Mathematics MathRight Arrow
  • Pre-Req Knowledge (Return to Contents)

    A basic knowledge of the parts of the digestive system and how they interact, as provided in the Teacher Background section or in the Intro/Motivation section of the TeachEngineering Digestive System lesson.

    Learning Objectives (Return to Contents)

    After this activity, students should be able to:
    • Describe how simulation is used to test the human body's reaction to medication.
    • Explain how engineers can directly and indirectly help people who are suffering from medical issues, specifically those relating to the digestive system.
    • Describe the function of the stomach in the human digestion process.

    Materials List (Return to Contents)

    Each group needs:
    • 60 mL (¼ cup) flour
    • 30 mL (1/8 cup) corn starch
    • 60 mL (¼ cup) sugar
    • 30 mL (1/8 cup) vegetable oil
    • 1 paper plate
    • 4 small paper or plastic bowls or cups
    • 1 clear plastic cup
    • 1 cup clear diet (to avoid stickiness) soda
    • 1 small plastic spoon
    • 2 pieces of color-coated candy per group (Runts or Skittles work well)
    • Recipe and Fraction Worksheet, one per person
    For the entire class to share:
    • marker, to write team names on plastic cups
    • 1 cup clear diet soda in a plastic cup (for experiment control)
    • timer

    Introduction/Motivation (Return to Contents)

    Sarah is a fifth-grade student with an extremely sensitive stomach that is irritated by certain foods and many medications. Sarah recently came down with an illness that caused her to have a high fever, among other symptoms. Her mother wants to help Sarah fight the fever by giving her some aspirin, but she is afraid that the medicine might make Sarah's stomach hurt. Can you think of some ways you might be able to help Sarah? (Possible answers: Have Sarah take the medication with food, use a different type of medication that does not cause stomach pain, use a coated aspirin, drink fluids and take a cooling sponge bath, have Sarah take the aspirin with another type of medication that helps stomach pain, etc.)
    Many medicines help our bodies fight sicknesses and diseases, but can also make our stomachs hurt. Can anyone tell me where the stomach is in the digestive system and what it does? (Refer to the Teacher Background information in the TeachEngineering Digestion Simulation lesson.) To prevent this stomach pain while still allowing the medication to get into our bodies, engineers and pharmacists have developed pill coatings that do not dissolve until after they have passed through our stomachs. These specially-coated pills are called "enteric-coated" pills or tablets.
    Today, we are going to help Sarah by acting as engineers and developing our own "enteric" coating. We will create a recipe for our coating, and then test it by observing its effectiveness in protecting a piece of candy placed in an environment that simulates the environment found in our stomachs. Before we get started, why is it better to test the pill in a simulated environment rather than testing it on a human? (Possible answers: The coating could fail and make the person's stomach hurt, it is easier to observe how the pill dissolves in the simulated environment, etc.). Then, just like engineers, we will analyze our coating and make suggestions for improvements to our design.

    Vocabulary/Definitions (Return to Contents)

    bioengineering: The use of artificial tissues, organs or organ components to replace damaged or absent parts of the body, such as artificial limbs and heart pacemakers. Source: The Oxford Pocket Dictionary of Current English, http://encyclopedia.com/doc/1O999-bioengineering.html
    biomedical engineer: A person who blends traditional engineering techniques with the biological sciences and medicine to improve the quality of human health and life. Biomedical engineers design artificial body parts, medical devices, diagnostic tools, and medical treatment methods.
    engineer: A person who applies his/her understanding of science and math to creating things for the benefit of humanity and our world.
    enteric: Of or pertaining to the enteron (the digestive tract or intestines). A medicinal preparation treated to pass through the stomach unaltered and disintegrate in the intestines.
    simulation: Imitating the behavior of some situation or process, especially for the purpose of study or experimental testing.
    soluble: Capable of being dissolved or liquefied.


    A protective coating can serve a variety of functions: Protecting the chemical components in a pill during packaging and handling; protecting the pill from temperature, moisture or light during storage; covering the bad taste of the pill chemicals; smoothing the edges so it is easier to swallow; helping the pill resist digestion to protect certain parts of our digestive system; providing an extended dose of medication; providing a surface for printing; and enhancing the image of the drug for marketing purposes. Engineers design coatings and coating systems to fulfill these functions. For more in-depth background, see the attached Protective Pill Coatings Teacher Background Sheet.

    Before the Activity

    • Gather materials and measure specified amounts of flour, corn starch, sugar and vegetable into individual bowls.
    • Make enough copies of the Recipe and Fraction Worksheet to provide one per person.

    With the Students

    1. Divide the class into groups of two or three students each.
    2. Pass out worksheets and materials to each group (see Figure 1).
    3. Discuss with the class the different properties of each ingredient. Oil helps the dry ingredients stick together, helps make the mixture less sticky, and makes the coating less soluble. Flour and cornstarch are thickening agents with fairly similar properties. They also improve the workability of the overall mixture. Sugar thickens the mixture to some extent and makes the texture grainier, but can also make it less soluble when used in the right proportion, thereby improving its performance as a protective coating.
    4. Before any mixing is done, have student teams decide amongst themselves how much of each ingredient (in spoonfuls) they think they want in their coatings. These become their recipes, which they document on their worksheets.
    5. Following their recipes, direct students to begin mixing their coatings on paper plates (see Figure 1). If a team feels that more of a certain ingredient is called for, have them carefully measure it and add it into the mixture, remembering to make the changes to the recipe on their worksheets.
    Photo shows amounts of flour, sugar, corn starch and oil in clear plastic cups arranged around a paper plate and plastic spoon on a desktop.
    Figure 1. The activity set-up for mixing a pill coating.
    1. When a group has finished creating their coating mixture and recipe, have them apply the coating to a piece of candy (see Figure 2). Encourage students to make a thin and sleek design so the pill is easy to swallow, inexpensive to ship, and requires less packaging.
    Photo shows a piece of candy covered with the beige mixture (coated) next to a piece of red candy (uncoated) on a paper plate.
    Figure 2. Example coated candy "pill," ready to test.
    1. When all of the groups are finished, have a representative from each bring their coated candy to the front of the class. For each team, fill a plastic glass half full with clear soda, plus one extra cup of clear soda for an uncoated piece of candy (so students can see their coatings' effect on the dissolving rate of the candy). Label the cups with a marker so each group's cup can be easily identified.
    2. With the timer ready, and at the same time, have students drop their coated candies into their cups of clear soda, while the teacher drops an uncoated candy into its cup of clear soda as a control (see Figure 3).
    Photo shows an uncoated piece of reddish candy and a whitish coated piece of candy in separate cups of clear soda.
    Figure 3. Beginning the timed test.
    1. Allow the candy to sit in the soda for 10 minutes (see Figure 4). After several minutes, if the coatings do not look like they are dissolving, have one student from each group stir their coated candy in its soda cup until the 10 minutes is over. Ask students: How does this step simulates a pill going through the human digestive tract? (Answer: This simulates the acidic environment of the stomach, as well as its churning and agitating movement.) Why is it better to test the pill in a simulated environment rather than testing it on a human? (Possible answers: The coating could fail and make the person's stomach hurt, it is easier to observe how the pill dissolves in the simulated environment, etc.).
    Photo shows two clear drinking cups, one with an unchanged coated candy piece in clear liquid, and the other with an uncoated candy piece surrounded by a cloudy yellow liquid.
    Figure 4. After about eight minutes have passed.
    1. While waiting, keep students busy with another class activity or by having them draw ads that describe the benefits of their pill coatings.
    2. After 10 minutes have passed, have students remove their pieces of coated candy from the soda-filled cups (see Figure 5). As a class, make observations about which coating did the best job of protecting the candy "pill" and compare the coating recipes for each group to see what did and did not work. How did the coatings perform, compared to the uncoated control "pill," and compared to the various team recipes?
    3. Have students calculate on their worksheets the fractions represented by each ingredient in their recipes. Compare recipes among teams, and discuss as a class, as described in the Assessment section. What are the relationships between performance and proportion of certain ingredients? What are the advantages and disadvantages of using certain materials?
    Photo shows three pieces of candy: an untested piece (red), an uncoated piece after testing (white and smaller), and a coated piece after testing (red).
    Figure 5. Comparing results.
    1. Using what they learned from analyzing the testing results and original recipes, direct each group to write down a new and improved coating recipe.
    2. Following their new recipes, have each team mix up a new coating batch. Do not allow them to make changes to their recipes during this stage.
    3. Repeat the same procedure for coating and testing, and then compare the results again as a class. What improvements were made?
    4. Conclude by reflecting on the activity in terms of the universal steps of the engineering design process: Ask, Imagine, Plan, Create and Improve, as described in the Assessment section. These are the steps engineers go through in designing new products and processes.

    Safety Issues (Return to Contents)

    • The activity materials have the potential to be extremely messy, so emphasize cleanliness and keep cleaning materials nearby. Consider laying down newspaper on and around the desks as protection from spills.

    Troubleshooting Tips (Return to Contents)

    To make very sticky concoctions more workable, add extra flour or corn starch.
    To prevent students from making a super-thick coating, set a limit on the maximum thickness permitted. Constraints like this are typical in real-world engineering design projects.

    Pre-Activity Assessment

    Class Discussion: Have students contribute to a class discussion about which foods or medications make their stomachs hurt (Possible answers: Spicy foods, soft drinks, milk, pain medications such as aspirin, Advil or Aleve). Discuss possible solutions to these problems. (Possible answers: Taking pills with food, taking enteric-coated rather than uncoated pills, stomach medications, avoiding certain types of foods, etc.)

    Activity Embedded Assessment

    Recipe Analysis: Have students calculate on their Recipe and Fraction Worksheets the fraction of the entire coating represented by each individual ingredient. Have teams compare their recipe breakdowns to other groups, looking for relationships between performance and the proportion of certain materials in the recipe. Discuss with the students possible drawbacks or advantages to using a higher proportion of certain ingredients, aside from the coating's performance during the test phase. (Possible answers: A high proportion of sugar makes the pill taste better and easier to swallow, a high proportion of flour or cornstarch makes the coating more workable and allows for a thinner application, which decreases packaging and shipping costs, etc.). Ask students to describe the balance that we are trying to achieve with all these variables. (Answer: We're trying "protect the pill," but also get the most other advantages and the fewest other disadvantages.)

    Post-Activity Assessment

    Class Discussion/Design Process: List all of the steps in the engineering design process as a class: Ask, Imagine, Plan, Create, Improve. Use the engineering design process graphic at the Museum of Boston's Engineering is Elementary website as an overhead transparency or slide for depicting the process to the class: http://www.teachersdomain.org/assets/wgbh/eng06/eng06_doc_lpaengprocess/eng06_doc_lpaengprocess.pdf
    As a class, discuss what goes on during each step of the process and relate each step to some part of the activity just performed. (Example: Ask – in this step, we talked about a problem and asked everyone how stomach pain has been treated in the past; Imagine – in this step, we brainstormed ideas for helping Sarah with her stomach pain, chose to make a pill coating, and decided which materials to use in the coating; Plan – in this step, we wrote out a recipe for the coating mixture; Create – in this step, we mixed the ingredients in the planned proportions, made adjustments, and tested the coating; Improve – in this step, we analyzed the recipe based on its performance during testing and compared to other groups' recipes, created an improved recipe, mixed the ingredients together, and tested the new coating.)

    Activity Extensions (Return to Contents)

    Have students research the different materials used as pill coatings and the different mechanical systems used to coat pills.
    Redo the experiment and challenge the students to design their coatings based on taste, marketability, cost and ease of shipping and handling while still meeting a certain benchmark protection time (such as 10 minutes, 15 minutes, etc.) during the test phase.

    Activity Scaling (Return to Contents)

    • For lower grades, eliminate one or two of the dry ingredients to make the recipes simpler.
    • For upper grades, add additional ingredients such as salt, corn syrup or water to make the recipes more complex. Lead a discussion to explore why certain items were better pill coating ingredients than others and try to determine what function each ingredient served.
    • For upper grades, turn this activity into a competition by challenging each group to make their pill dissolve at a specified time (that is, not too early and not too late).

    Additional Multimedia Support (Return to Contents)

    See a photograph of shellac excretions at the Spectroscopy NOW website: http://www.docstoc.com/docs/100688383/Protective-Pill-Coatings
    See a photograph of unprocessed shellac at the Lexportex (India) Pvt. Ltd. website: http://www.indianshellac.com/pics/pic2.jpg
    See a photograph of a supercell tablet coater at the GEA Process Engineering Inc. website: http://www.niroinc.com/images/pharma_systems/supercell_tablet_coater.jpg
    See an engineering design process graphic at the Museum of Boston's Engineering is Elementary website: http://www.teachersdomain.org/assets/wgbh/eng06/eng06_doc_lpaengprocess/eng06_doc_lpaengprocess.pdf

    Dictionary.com. Lexico Publishing Group, LLC. Accessed December 30, 2008. (Source of some vocabulary definitions, with some modifications) http://www.dictionary.com

    Pharmaceutical Glaze. Last updated May 11, 2008. Wikipedia Free Online Encyclopedia. Accessed July 7, 2008. http://en.wikipedia.org/wiki/Pharmaceutical_glaze

    Tablet. Last updated July 5, 2008. Wikipedia Free Online Encyclopedia. Accessed July 7, 2008. http://en.wikipedia.org/wiki/Tablet

    The Tablet Coating Process Design and Control. Last updated January 2008. Invensys, Eurotherm Life Sciences Solutions. Accessed December 30, 2008. http://www.eurotherm.com/industries/life-sciences/applications/tablet-coating/


    Jacob Crosby, Todd Curtis, Malinda Schaefer Zarske, Denise W. Carlson


    © 2008 by Regents of the University of Colorado.

    Supporting Program (Return to Contents)

    Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

    Acknowledgements (Return to Contents)

    The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.
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