Mitigating Microplastics

Development and Evaluation of a Middle School Curriculum

by Marie Kowalski and Tracy Crews



Microplastics are plastic marine debris less than five millimeters across. Microplastics are a threat to the health of our ocean. One important way to reduce microplastics in our ocean is to educate people about the issue, particularly future decision-makers. A middle school curriculum was developed using current scientific data and evaluated using the Context, Input, Process, Product (CIPP) model. The curriculum includes lessons on sources, impacts, and solutions to microplastics. Students participating in the curriculum demonstrated detailed knowledge and awareness of microplastics as well as increased feelings of personal responsibility.


Microplastics, marine debris, curriculum, middle school, curriculum evaluation


Our ocean is a valuable resource that provides important services including fisheries, recreation, and habitat for many organisms. The global health of our ocean is threatened by marine debris or litter in the ocean. Most marine debris is plastic (Thiel et al. 2013) and can range in size from abandoned boats to microplastics less than five millimeters across (Law and Thompson 2014). Marine debris is everywhere, and it is largely preventable through changes in people’s behaviors. Reducing marine debris, however, is a complex problem.

While picking up litter is important, education and scientific research are also critical components of reducing marine debris (Thompson, Moore, vom Saal, and Swan 2009). Awareness of marine issues is associated with feeling concern for the environment (Gelcich et al. 2014). Inspiring and empowering young people to take action is an important part of reducing marine debris.

This article describes a three-part middle school curriculum incorporating current research on microplastics. An overview of the curriculum development and evaluation is discussed. An excerpt from the curriculum is included with access to the full curriculum available online. While the curriculum was designed and evaluated with a formal middle school classroom in mind, the lesson activities can also be adapted for use in informal settings.



Sources and Sinks

It was estimated that more than five trillion pieces of plastic are floating in the ocean and over 90% are microplastics (Eriksen et al. 2014). Most marine debris (estimated 80%) originates on land (Derraik 2002). Microplastics primarily enter the ocean when larger plastic marine debris fragments (and small plastics) are directly deposited in the ocean (Browne 2015). Small plastics in personal care products such as some face washes and toothpastes, as well as plastic fibers in laundry lint, go down household drains and are not removed by water treatment facilities (Fendall and Sewell 2009).

PHOTO – Small plastic particles in personal care products called microbeads enter household drains and are not removed by water treatment facilities. Courtesy of Marie Kowalski.

Possible Impacts

Once in the ocean, the impacts of microplastics are largely unknown. Ongoing research has identified potential impacts such as the accumulation of toxins on the surface of microplastics (Mato et al. 2001) and organisms’ ingestion of plastics. Microbes have also been shown to colonize on the surface of microplastics, possibly being transported to new parts of the ocean or sinking plastic to deeper waters (Zettler, Mincer, and Amaral-Zettler 2013).

Organisms such as plankton (Cole et al. 2013) and filter feeders such as oysters (Van Cauwenberghe and Janssen 2014) have been reported to ingest microplastics along with several species of fish and seabirds (Codina-García, Militão, Moreno, and González-Solís 2013). The impacts of microplastics after consumption is unclear. Microplastics are found from the surface to the bottom of the ocean all over the world, making their impacts on the marine environment a global concern.



For an issue that has no one solution, effective methods to address marine debris will require creativity and collaboration among many groups. Three categories of solutions include legislation, education, and individual actions.

  • Legislation: The federal Microbead-Free Act of 2015 banned the manufacture and sale of personal care products with plastic microbeads.
  • Education: Educating people about marine debris has the potential to inspire reduction of marine debris at multiple scales.
  • Individual Actions: Individual actions such as recycling and avoiding plastic products can reduce our personal plastic contribution and inspire others to change, thereby having a larger impact.




The microplastics curriculum was created through the backwards planning design of Wiggins and McTighe (2005). Lessons were grounded in enduring understandings and learning objectives aligned with middle school Next Generation Science Standards (NGSS), Common Core State Standards (CCSS), and Ocean Literacy Principles (OLP). Lessons were developed using data provided by researchers working in the field.


The curriculum consists of three lessons designed for sixth through eighth grade students:

  1. “Bags, Bottles, and Beads: Sources of Microplastics”: Students investigate personal care products with microbeads, explore major sources of microplastics, and work with data on microplastics abundance in the Pacific Ocean.
  2. “Small Plastics, Big Problem”: Students simulate the fragmentation of plastic marine debris to determine how its surface area changes and then work with data from the Columbia River Estuary in Oregon to explore potential impacts of plastics in waterways.
  3. “Mitigating Microplastics”: Students work in groups to generate solutions to the problem of microplastics and implement their ideas. The curriculum available online contains a set of teacher lesson plans with aligned standards, materials, lesson outlines, extension and adaptation suggestions, and background content information. A presentation slide show is also available along with student handouts and an answer guide.



Evaluation Model

The evaluation of this curriculum was based on the Context, Input, Process, Product (CIPP) model (Stufflebeam and Coryn 2014). This model was chosen because of its flexibility and ability to be used as a model for both the formative and summative evaluation.

The goal of the formative evaluation was to get feedback on the initial curriculum from students and assess its usefulness to teachers. Data collected during the formative evaluation was used to revise the curriculum.

The goal of the summative evaluation was to evaluate the effectiveness of the final curriculum and document changes in participants. The summative evaluation was guided by two questions:

  1. To what extent do knowledge, attitudes, and beliefs change after participating in this microplastics curriculum?
  2. How does understanding and behavior change after participating in this microplastics curriculum?


Data Collection

Formative evaluation data was collected in two parts: pilot teaching and a teacher focus group. The pilot version of the curriculum was taught at two marine science summer camps with a total of 47 students between the ages of 12 and 15. Data on student questions and responses were collected via researcher fieldnotes and used to revise the curriculum. The revised curriculum was reviewed by agroup of four middle school teachers, a curriculum resource liaison, and a K-12 liaison at a marine education facility. A focus group was held to obtain feedback on the content, layout, usability, and likelihood that the curriculum would be used in the classroom. This feedback was also used to revise the curriculum.

Summative evaluation data was collected using pre- and post-surveys before the first lesson in the curriculum and after the last lesson of the curriculum was taught by the researcher. The survey was used with 110 students and three teachers in a total of seven classes. The concepts addressed in the survey included awareness, attitudes, beliefs, understanding, and behaviors, which are considered by Allen et al. (2008) to be components of science education “impact.” Data on student knowledge was collected using questions embedded in student materials.


Data Analysis

Quantitative data (awareness, attitudes, beliefs, numberof behaviors, and knowledge) was coded and analyzed in SPSS using descriptive and nonparametric statistical tests. Qualitative data (understanding, behaviors, and some knowledge items) was coded in Dedoose, a web application for mixed methods analysis, using a combination of in vivo (bottom up) coding and axial (top down) coding (Berg and Lune 2012).


Evaluation Results

The evaluation results are from the summative evaluation of the curriculum. Of the seven classes and 110 students who participated in the evaluation, 24% were in fifth or sixth grade, and 76% were in eighth grade. More than half (53%) of the students had not heard of microplastics before participating in the lessons.

Overall, eighth grade students scored higher on knowledge questions (defining marine debris and microplastics, articulating the abundance of microplastics, and explaining how surface area changes when an object fragments), with the exception of identifying sources of microplastics.

Additionally, all students struggled with explaining how the total surface area changed as marine debris fragmented over time. The mean score for students on this objective was 65%. The challenge was possibly due to the fact that Common Core State Standards do not include calculating the surface area until seventh grade or may reflect students’ reliance on mathematical formulas (Zacharos 2006). This section of the curriculum is most appropriate for students who are already familiar with calculating surface area.

The shifts in student misconceptions and types of behaviors suggest that the curriculum did get students thinking about the issue in a more accurate way, correcting some misconceptions.

Generally, attitudes about the scope and severity of the microplastics issue and beliefs that students could influence the problem increased after participating in the curriculum.

Students were more worried about the issue, but concern is important when combined with knowledge of solutionoriented behaviors. Self-efficacy was generally high among students, which can be an opportunity to engage them in creating and implementing solutions in the classroom and beyond. Selected evaluation results are highlighted in Table 1 below.

Concept Results


Post lessons, students scored 80% or above on every objective, except in surface area students scored 65%.



After the lessons, students did list more behaviors to reduce microplastics in the ocean than listed previously. The mean number of behaviors listed per student increased from 3.52 to 3.83.

Pre-survey behaviors were focused on managing waste (recycling and not littering).

Post-survey behaviors were focused on managing consumption (buying non-plastic items or reducing their use of plastics).



After the lessons, students tended to include fewer misconceptions (the mean number of misconceptions per student decrease from 0.51 in the pre-survey to 0.35 in the post survey) and more detailed explanations in their responses. Some students showed misconceptions after the lessons that all plastic floats and microplastics kill all marine life.



Students tended to believe they could make a difference in the microplastics issue both before and after the lessons.



After the lessons, students tended to:

  • Be significantly more worried about the issue (p < .001, Z = 3.43)
  • Think microplastics are a more challenging problem
  • Be unsure about the impacts of microplastics on people


This middle school microplastics curriculum was developed and evaluated using formative and summative techniques. Because the curriculum was evaluated in a rural, coastal school district in Oregon, the results cannot be generalized to other communities.

In this context, however, the microplastics curriculum was effective in raising awareness, knowledge, and feelings of personal responsibility among students as well as developing more specific understanding of microplastics. The first lesson from this curriculum is outlined here, with images of the supporting student materials. The full curriculum is available online. A link is available in the resources section of this article.



Next Generation Science Standards

ESS3.C: Human Impacts on Earth Systems Human activities have significantly altered the biosphere, sometimes damaging or destroying natural habitats and causing the

extinction of other species. But changes to Earth’s environments can have different impacts (negative and positive) for different living things. (MS-ESS3-3)


Patterns Graphs, charts, and images can be used to identify patterns in data. (MS-ESS3-2)

Ocean Literacy

6.D Human activity contributes to changes in the ocean and atmosphere.

6.D.18 Pollutants move from the land into the ocean as water flows through watersheds via runoff and rivers.


Enduring Understandings

Everyone’s actions have an impact (both positive and negative) on the environment.



  • Students will define marine debris and microplastics
  • Students will explain sources of microplastics


  • One 90-minute lesson


  • Two sealing jars for each group/pair
  • Water (enough to fill each jar about half full)
  • Liquid soap or face wash with microbeads
  • Liquid soap or face wash with natural exfoliators
  • Student notebook: “Bags, Bottles, and Beads”
  • Sink
  • Coffee filters
  • Jar/bucket for microbead disposal


  • Divide students into groups of 2-3
  • With two jars for each group, label half the jars “A” and the other half “B”
  • Place about a tablespoon of soap in each jar
  • Soap with microbeads in jar “A”
  • Soap with natural exfoliators in jar “B”
  • Have a disposal jar/bucket for microbead soap when the activity is over




Say: Look around the room and silently find as many plastic objects as you can in 10 seconds…go! Time students for 10 seconds, then have students share some of the objects they identified.


Ask: Raise your hand if you agree that there is a lot of plastic in this classroom? If you agree that we use a lot of plastic in our daily lives?

Say: We use plastic every day, and many of the plastics are single-use. They are designed to be thrown away after being used once. We might not realize which products have plastic, and we don’t always know what happens to them after they are thrown away.


Explore—”Soap, Suds, and…Plastic?”

Say: Some products with plastics might surprise you. First, we will talk a little about plastic itself, and then you will have a chance to investigate for yourself. Students complete guided notes in their notebooks.


Presentation: Slides include the text from the notebook with the blanks filled in.

Say: Polyethylene is the plastic most microbeads are made of, and you can identify products with microbeads by looking at the ingredients for polyethylene. Repeat after me, “polyethylene.”

Handout: an “A” and “B” jar to each student group, don’t tell them which soap is which.


Students compare the size, shape, color, and any additional properties of the two soaps to determine which one contains plastic.

Courtesy of Marie Kowalski



As an alternative to the first activity “Soap Suds and… Plastic,” consider completing the challenge using just face wash with natural exfoliators. Have students observe and draw the particles, and then explain that some soaps used to have plastic instead of the natural material. Ask students to imagine that those particles are plastic to get an idea of the number of microbeads that might enter the ocean from one product. Emphasize that there are other sources of microplastics that enter waterways, including plastic fibers from clothing.

Students read and follow the directions in their notebooks.

Presentation: Slides also have activity directions for reference.

  • Students first make observations of the two jars (color, texture, size and shape of particles, etc.).
  • Students fill jars halfway with water, close it tightly, and shake the jars to dissolve the soap (there shouldn’t be any soap stuck to the bottom).
  • Students write down what they observe and draw pictures in their notebooks of how the particles behave inside the soaps. Students answer the questions in their notebooks.

Ask: What did you notice that was different between the two jars? How did the particles in the soaps behave? Which one do you think has plastic in it? What evidence do you have? Reveal the answer, that “A” has microplastics in it!

Misconception Alert! Plastic microbeads will float in the water, but not all microplastics float! Microplastics can be found at many depths, including the ocean floor. Before moving on to the next part of the lesson, clarify that while the plastic microbeads in the investigation floated, not all microplastics float in the ocean.

  • Students read the “newspaper clipping” from their notebook and answer the question.

Discuss: Why is the problem of microplastics not solved? Do you think this is a helpful law? Why or why not?

Debrief: “How do microplastics make it to the ocean?”

Say: One of the reasons the microplastics problem is not solved by this law is that there are many other ways microplastics get into the ocean.

Presentation: Slides show “main sources of microplastics.” See student example for notes. Students complete guided notes from their notebooks.

Say: There are two main ways that microplastics enter the ocean. One is directly as small pieces (show microplastics definition and have a student read it aloud). Plastics in toothpaste, face wash, and laundry lint can go directly into the ocean. Most microplastics are from larger plastic marine debris items that are fragmented once they get to the ocean (show marine debris definition and have a student read it aloud). Nurdles are small plastic pieces used in factories to make plastic products.

Practice: “Real Researcher: Angel White”

Say: Now that we know about microplastics and where they come from, we are going to learn about a researcher who studies microplastics.

This diagram describes the flow of the curriculum evaluation, beginning with the needs assessment and ending with the dissemination of the curriculum. Courtesy of Marie Kowalski


Students will read “Real Researcher: Angel White” from their student notebook as an introduction to her data. Students will answer the questions about Angel’s data. See student example for correct responses. Answers are based on the data table and reading.

Ask: Why do you think scientists study microplastics in the ocean? What should scientists like Angel do with their results?

Clean Up

To keep microbeads from going down the sink drain, you can use a coffee filter to remove the microbeads from the soap. You can dry them and put them in a container to show the amount of plastic in the product!




Mitigating Microplastics:

Marine Debris

NOAA Marine Debris Program: http://marinedebris.noaa. gov/info/plastic.html

Study on the abundance of plastic marine debris: http://

Article on plastic fibers in laundry:


National Science Foundation Report: /framework-evaluating-impactsbroadening-participation-projects_1101.pdf



Allen, S., P.B. Campbell, L.D. Dierking, B.N. Flagg, C. Garibay, R. Korn, D.A. Ucko. (2008). Framework for Evaluating Impacts of Informal Science Education Projects. (A. J. Friedman, Ed.). National Science Foundation. Retrieved from

Berg, B.L., and H. Lune. (2012). Qualitative Research Methods for the Social Sciences (8th ed.). Upper Saddle River, NJ: Pearson Education.

Browne, M.A. (2015). Sources and pathways of microplastics to habitats. In Marine Anthropogenic Litter. M. Bergmann, L. Gutow, and M. Klages (Eds.). Cham, Switzerland: Springer International Publishing.

Codina-García, M., T. Militão, J. Moreno, and J. González-Solís. (2013). Plastic debris in Mediterranean seabirds. Marine Pollution Bulletin, 77(1-2): 220-226.

Cole, M., P. Lindeque, E. Fileman, C. Halsband, R. Goodhead, J. Moger, and T.S. Galloway. (2013). Microplastic ingestion by zooplankton. Environmental  Science & Technology, 47(12): 6646–6655.

Derraik, J.G.B. (2002). The pollution of the marine environment by plastic debris: A review. Marine Pollution Bulletin, 44(9): 842-852.

Eriksen, M., L.C.M. Lebreton, H.S. Carson, M. Thiel, C.J. Moore, J.C. Borerro, and J. Reisser. (2014). Plastic pollution in the world’s oceans: More than 5 trillion plastic pieces weighing over 250,000 tons afloat at sea. PLoS ONE, 9(12): e111913.

Fendall, L.S., and M.A. Sewell. (2009). Contributing to marine pollution by washing your face: Microplastics in facial cleansers. Marine Pollution Bulletin, 58(8): 1225-1228.

Gelcich, S., P. Buckley, J.K. Pinnegar, J. Chilvers, I. Lorenzoni, G. Terry, and C.M. Duarte. (2014). Public awareness, concerns, and priorities about anthropogenic impacts on marine environments. Proceedings of the National Academy of Sciences, 111(42): 15042-15047.

Glatthorn, A.A., F. Boschee, B.M. Whitehead, and B.F. Boschee. (2015). Curriculum Leadership: Strategies for Development and Implementation (4th ed.). New York, NY: SAGE Publications, Inc.

Law, K.L., and R.C. Thompson. (2014). Microplastics in the seas. Science, 345(6193): 144-145.

Mato, Y., T. Isobe, H. Takada, H. Kanehiro, C. Ohtake, and T. Kaminuma. (2001). Plastic resin pellets as a transport medium for toxic chemicals in the marine environment.  Environmental Science & Technology, 35(2): 318-324.

Microbead-Free Waters Act of 2015, 21 U.S.C. § 301.

Thiel, M., I.A. Hinojosa, L. Miranda, J.F. Pantoja, M.M. Rivadeneira, and N. Vásquez. (2013). Anthropogenic marine debris in the coastal environment: A multi-year comparison between coastal waters and local shores. Marine Pollution Bulletin, 71(1–2):307-316.

Thompson, R. C., C.J. Moore, F.S. vom Saal, and S.H. Swan. (2009). Plastics, the environment and human health: Current consensus and future trends. Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1526): 2153-2166.

Van Cauwenberghe, L., and C.R. Janssen. (2014). Microplastics in bivalves cultured for human consumption. Environmental Pollution, 193: 65-70.

Wiggins, G., and J. McTighe. (2005). Understanding by Design (2nd ed.). Upper Saddle River, NJ: Pearson.

Zacharos, K. (2006). Prevailing educational practices for area measurement and students’ failure in measuring areas. The Journal of Mathematical Behavior, 25(3):224-239.

Zettler, E. R., T.J. Mincer, and L.A. Amaral-Zettler. (2013). Life in the “plastisphere”: Microbial communities on plastic marine debris. Environmental Science & Technology, 47(13): 7137-7146.


MARIE KOWALSKI is a recent graduate of the Marine Resource Management program at Oregon State University. Her research interests include incorporating authentic science in classroom settings and communicating marine science.

TRACY CREWS oversees Oregon Sea Grant’s marine education programs at Hatfield Marine Science Center. Tracy holds a bachelor of science degree in marine biology, a master of science degree in marine science, and has worked in fisheries research, resource management, and education for over 25 years.


This article originally appeared in Currents, the journal of the National Marine Educators Association. Reprinted with permission.