Students are presented with a short lesson on the Coulter principle—an electronic method to detect microscopic particles and determine their concentration in fluid. Depending on the focus of study, students can investigate the industrial and medical applications of particle detection, the physics of fluid flow and electric current through the apparatus, or the chemistry of the electrolytes used in the apparatus.
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- International Technology and Engineering Educators Association: Technology
- F. Many tools and devices have been designed to help provide clues about health and to provide a safe environment. (Grades 3 - 5)  ...show
- North Carolina: Math
- Use units as a way to understand problems and to guide the solution of multi-step problems; choose and interpret units consistently in formulas; choose and interpret the scale and the origin in graphs and data displays. (Grades 9 - 12)  ...show
- Graph linear and quadratic functions and show intercepts, maxima, and minima. (Grades 9 - 12)  ...show
- North Carolina: Science
- Analyze the nature of moving charges and electric circuits. (Grades 9 - 12)  ...show
- Analyze systems with multiple potential differences and resistors connected in series and parallel circuits, both conceptually and mathematically, in terms of voltage, current and resistance. (Grades 9 - 12)  ...show
- Describe qualitatively how a particle changes the resistance between two electrodes as it moves through an aperture and how that resistance is measured.
- Describe the basic functioning of a Coulter counter, how the original Coulter counters improved blood cell counts, and how these improvements benefited patients and medical staff.
Lesson Background and Concepts for Teachers
Coulter Electric Sensing Zone Method
- Simple Coulter Counter - Student teams build their own Coulter counters using simple materials and data acquisition equipment. They take data, make graphs and count particles in prepared "paint samples."
- What is the relationship between current and voltage? If the voltage over a circuit is increased, what happens to the current? (Answer: The voltage is the electrical potential difference between two points that cause charged particles, the current, to move through a circuit. You can visualize the voltage difference as a height difference of a hill, and the current as water flowing downhill. A battery or other electrical energy source can be visualized similar to a pump in a fountain to cause a continuous flow. If the voltage is increased, the water moves faster.)
- What is the relationship between current and resistance? If the resistance over a circuit is increased, what happens to the current? (Answer: Resistance is a measure of how difficult it is for current to move through the circuit. If the resistance in a circuit is increased, the current decreases.)
- How do the length, cross-sectional area, and material composition of a resistor affect its resistance? (Answer: You can visualize this question by thinking of a school hallway. A long, skinny hallway is harder to move students through than a wide, short hallway. [Think of examples in your school building.] The material composition can be thought of as the obstacles in the hallway. A room filled with desks is harder to move a lot of students through than an empty hallway. Length of a resistor increases resistance, cross-sectional area decreases resistance and conducting materials have less resistance than insulating materials.)
Lesson Summary Assessment Homework
Additional Multimedia Support
The Coulter Counter Model A Showcases at Chemical Heritage Foundation Exhibit. Beckman Coulter, Inc. Accessed August 31, 2010. http://www.beckmancoulter.com/resourcecenter/diagtoday/articles/DTO_Issue5_08/DTO_Issue5_08_ModelA.asp.
The Coulter Particle Counter/Sizer. Science-Projects.com. Accessed August 31, 2010. https://www.science-projects.com/Coulter/Coulter.htm
Graham, M. D. "The Coulter Principle: Foundation of an Industry." Journal of the Association for Laboratory Automation. December 2003: 72-81. Accessed January 8, 2014. https://jla.sagepub.com/content/8/6/72.full.pdf+html
Houwen, Berend. "Fifty years of hematology innovation: the Coulter Principle—Retrospective." Published November 2003. Medical Laboratory Observer, CBS Business Network. Accessed February 2011. https://findarticles.com/p/articles/mi_m3230/is_11_35/ai_111351102/
The ingredients of paint and their impact on paint properties. Published November 2005. Buildings.com. Accessed September 1, 2010. http://www.buildings.com/ArticleDetails/tabid/3321/ArticleID/2846/Default.aspx
Our Heritage—Wallace H. Coulter. Beckman Coulter, Inc. Accessed August 2009. http://www.beckmancoulter.com/hr/ourcompany/oc_WHCoulter_bio.asp.
U.S. Patent 2656508. Means for counting particles suspended in a fluid, October 20, 1953, Wallace H. Coulter.
Wallace H. Coulter (1913-1998) – Automated Blood Analysis. Updated August 2000. Lemelson—MIT Program. Accessed August 31, 2010. http://web.mit.edu/invent/iow/coulter.html
Jean Stave, Durham Public Schools, NC, Chuan-Hua Chen, Mechanical Engineering and Material Science, Duke University
© 2013 by Regents of the University of Colorado; original © 2010 Duke University
NSF CAREER Award and RET Program, Mechanical Engineering and Material Science, Pratt School of Engineering, Duke University
Last modified: February 11, 2016