Hands-on Activity: If You're Not Part of the Solution, You're Part of the Precipitate!

Contributed by: Bio-Inspired Technology and Systems (BITS) RET, College of Engineering, Michigan State University

Photo from above looking into a glass beaker shows a pool of cloudy white material at the bottom of the vessel.
Students separate solid calcium phosphate from solution.
Copyright © 2012 Angela D. Kolonich, Michigan State University


Students continue the research begun in the associated lesson as if they were biomedical engineers working for a pharmaceutical company. Groups each perform a simple chemical reaction (to precipitate solid calcium out of solution) to observe what may occur when Osteopontin levels drop in the body. With this additional research, students determine potential health complications that might arise from a new drug that could reduce inflammatory pain in many patients, improving their quality of life. The goal of this activity is to illustrate biomedical engineering as medical problem solving, as well as emphasize the importance of maintaining normal body chemistry.
This engineering curriculum meets Next Generation Science Standards (NGSS).

Engineering Connection

Biomedical engineers often gather information by observing experiments that have already been performed, or performing simple lab experiments. After completing the research phase of the design process, which includes reading scholarly articles for already discovered information, engineers find other methods of obtaining information before developing a design proposal. Performing simple experiments to understand the information gathered in the reading phase is another way to obtain information about the engineering challenge.

Pre-Req Knowledge

Conduct the associated lesson before starting this activity.

Having background knowledge of the human body (as studied in anatomy) makes this activity a richer experience, for example, an understanding of the importance of body chemistry and electrolytes, and basic knowledge of the functioning of each body system.

Learning Objectives

After this activity, students should be able to:

  • Describe the importance of research in technological advancements.
  • Explain the importance of maintaining body chemistry homeostasis.

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Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

  • Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Making decisions about the use of technology involves weighing the trade-offs between the positive and negative effects. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • The design process includes defining a problem, brainstorming, researching and generating ideas, identifying criteria and specifying constraints, exploring possibilities, selecting an approach, developing a design proposal, making a model or prototype, testing and evaluating the design using specifications, refining the design, creating or making it, and communicating processes and results. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Requirements of a design, such as criteria, constraints, and efficiency, sometimes compete with each other. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Technological problems must be researched before they can be solved. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Synthesize data, analyze trends, and draw conclusions regarding the effect of technology on the individual, society, and environment. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Biotechnology has applications in such areas as agriculture, pharmaceuticals, food and beverages, medicine, energy, the environment, and genetic engineering. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Identify, research, and summarize current, topical advances in biomedical research and healthcare areas. (Suggested areas of initial focus including fetal tissue research, legalization of drugs, drug abuse, euthanasia, research fraud, use of non-human animals in research, genetic engineering, and universal health care. DOK 4
    • Biomedical science areas of personal interest
    • Key areas of human physiology towards which a major commitment of United States federal funding of biomedical research is applied
    (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
Suggest an alignment not listed above

Materials List

Each group needs:

Note: Chemical and lab materials available at science supply stores such as Flinn Scientific at http://www.flinnsci.com/

To share with the class:


Yesterday, we reviewed and practiced what biomedical engineers do during the research phase of the engineering design process, and today we are going to use the information we gathered to determine what the exact effects Osteopontin has on the body, and what health complications might occur in humans if we were to administer this drug.

(Spend a few minutes reviewing the answers to the three exit questions students completed the previous day as part of the associated lesson.)

We will begin by conducting a simple experiment to see what happens when solid calcium precipitates out of solution, and then think about how this may apply to the solutions present in our bodies.


biomedical engineering: The application of science, math and engineering principles to problem solving design that involves medicine and biology.

dissociate: A general process in which ionic compounds separate or split into smaller particles or ions, usually in a reversible manner.

electrolyte: Any substance that dissociates into ions when dissolved in a suitable medium.

engineering design process: A series of steps used by engineering teams to guide them as they develop new solutions, products or systems.

homogenous: Uniform in structure or composition.

precipitate: To separate (a substance) in solid form from a solution.

solution: A homogeneous, molecular mixture of two or more substances.



During the associated lesson, Pharmaceutical Research Design Problem, students read a scholarly article to learn what other researchers have already discovered about Osteopontin in the human body. During this activity, students continue the research phase of the engineering design process as it relates to developing a new pharmaceutical drug by conducting a simple illustrative lab experiment.

Once the lab experiment is done, use the Pharmaceutical Research Presentation to show students photographs of a precipitate as well information on forming a precipitate and research implications to help wrap up a discussion of how this change in calcium may affect the human body.

Before the Activity

  • Gather materials and lab supplies.
  • From conducting the associated lesson, students should already each have an Osteopontin Research Activity Worksheet with page 1 completed.
  • Prepare two solutions for each group, as described below. Note: The goal is to mix enough of each solid with 100 ml of distilled water so that it all dissolves and no solid remains in the bottom of the beaker. Start with a small amount (the size of a quarter) and add more until it takes some time for it all to dissolve. The more saturated the solution, the more precipitate will form. It may take 5-10 minutes of stirring to get it to dissolve. Add a little at a time to make sure it all dissolves and when it starts to take a long time to dissolve, stop adding and continue stirring until all the solid is dissolved.
  1. In one beaker, add 100 ml of distilled water. Add CaCl2 slowly and stir vigorously to dissolve the CaCl2. It may take 5-10 minutes of stirring until the solid dissolves to produce a saturated solution of CaCl2. Use a marker and a piece of masking tape to label the beaker: Ca+ and Cl-.
  2. In the other beaker, add 100 ml of distilled water. Add K3PO4 slowly and stir vigorously to dissolve the K3PO4. It may take 5-10 minutes of stirring until the solid dissolves to produce a saturated solution of K3PO4. Use a marker and a piece of masking tape to label the beaker: K+ and PO4 -.

With the Students

A young girl wearing safety glasses stirs a cloudy liquid in a glass beaker.
A student mixes the solutions to observe the phenomenon of a precipitate.
Copyright © 2012 Angela D. Kolonich, Michigan State University

  1. Distribute a Ca+,Cl- and a K+, PO4 - beaker, stirring rod and safety glasses to each group.
  2. Direct students to carefully mix the two solutions together and stir.
  3. It may take five minutes or so for the precipitate to form. Expect the solution to appear cloudy.
  4. Direct students to stop stirring and observe as the solid falls out of solution.
  5. Have students record their observations on their worksheets.
  6. Facilitate a discussion of the phenomenon. A double replacement reaction occurred with the following balanced equation: 3 CaCl2 + 2 K3PO4 = Ca3(PO4)2 + 6 KCl and solid calcium phosphate precipitated out.
  7. Remind students that we humans have all of these ions in our blood at all times. Certain molecules, like Osteopontin, help keep them in solution.
  8. Have students draw on their article research from the lesson to discuss worksheet questions 3 and 4 in their groups, and write down their answers.
  9. Bring together the class and show students slides 10-15 of the presentation to wrap up the activity.
  10. On slide 11, have students use their knowledge of anatomy to postulate what happens in the blood, urine and blood vessels when calcium salts precipitate out of solution. Biomedical engineers must have a good knowledge of anatomy and/or conduct further research to understand reactions consequences in the human body.
  11. Read slide 12 to students, the resulting research implications for what happens in the blood, urine and joint fluid.
  12. Show the remaining slides, which talk about vascular calcification and include images of kidney stones and gout.
  13. Facilitate a discussion of the effects of solid calcium salts on the blood, urine and synovial fluid. Expect students to use their knowledge of the human body to contemplate potential health complications from calcium salts forming in each of these three fluids.
  • In the blood, solid calcium can cause calcifications to occur, such as the depositing of solid calcium into vessel walls, making them hard and inflexible.
  • In urine, solid crystals can lead to the formation of crystals and eventually kidney stones.
  • In joint fluid, crystals can develop from the solid calcium causing inflammation and pain (gout).
  1. Conclude by collecting the completed worksheets and assigning the exit questions, as described in the Assessment section.


Safety Issues

  • Make sure students wear safety glasses so chemicals do not splash into their eyes during the lab.
  • For all other safety concerns, refer to the MSDS for the chemicals used.


Opening Review: Begin the activity by reviewing with the class their answers to the exit questions from the associated lesson, conducted the previous day. Clarify any misconceptions.

Observations: During the lab activity, observe student progress. Make sure students are following instructions accurately, completing their worksheets (page 2) and participating in discussions.

Worksheet: At activity end, collect the Osteopontin Research Activity Worksheets with students' research notes on page 1 (from the lesson) and lab observations and conclusions on page 2. Review their notes and answers to assess their understanding of the subject matter.

Written Exit Questions: To conclude, assign students to individually answer the following questions and submit for points. The next day, review the answers with students to clarify any misconceptions.

  1. Why is the maintenance of stable body chemistry important? Do you find this surprising? (Answer: Even a slight change in body chemistry can initiate a chain reaction that causes a diverse set of problems in the body. We do not understand all the chemicals and their complex interactions in our bodies. The natural chemical balance in our bodies is very important and we do not want to disturb it and cause problems.)
  2. Describe in your own words how extreme changes in Osteopontin levels can lead to kidney stones. (Example answer: Lowering levels of Osteopontin increases the chance that calcium salts will precipitate out of solution in the body. If solids form during the body's production urine, they can collect in the kidneys where they may become stuck in the tiny tubes. So extreme changes in Osteopontin levels can cause more solids to accumulate until kidney stones form.)
  3. (optional; for bonus points) If you were a biomedical engineer, what sort of design projects would you like to work on that would help in the care of human health? (Possible answers: As a medical problem solver, I would like to design medical implants [replacement joints, limbs, tissues or organs], develop pharmaceutical drugs, design surgical tools and methods, create diagnostic equipment, etc.)


Angela D. Kolonich


© 2013 by Regents of the University of Colorado; original © 2012 Michigan State University

Supporting Program

Bio-Inspired Technology and Systems (BITS) RET, College of Engineering, Michigan State University


The curricular material was supported by an NSF CAREER award (grant no. CMMI 1150376) and an NSF RET program (grant no. EEG 0908810) at Michigan State University. However, these contents do not necessarily represent the policies of the National Science Foundation and you should not assume endorsement by the federal government.

Last modified: August 23, 2017