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The Engaged Scientist

Monitoring Microplastics in Surface Water—A Pacing Guide for Grades 5–12

Connecting STEM Learning With Real-World Phenomena

Connected Science Learning July–August 2023 (Volume 5, Issue 4)

By Tracy Ostrom, Matthew Ferner, Alessandra Sutti, Stuart Robottom, and Sandro Sutti

Monitoring Microplastics in Surface Water—A Pacing Guide for Grades 5–12

The San Francisco Bay National Estuarine Research Reserve (SF Bay NERR) and the WestEd/University of California Berkeley (UCB) Global Learning and Observation to Benefit the Environment (GLOBE) Partnership created an opportunity for teachers to participate in a pilot study using a pacing guide on microplastics in local water bodies.

Microplastics, emerging pollutants of anthropogenic sources, have been recognized as a pervasive global threat to the health of aquatic and terrestrial ecosystems and are a growing ecological concern. Microplastics are defined as small pieces of plastic (5 millimeters or less) and include objects such as textile fibers and microbeads that are still used in cosmetics in some countries (UNEP 2017). Microplastics are a widespread pollutant in the oceans and have been observed in numerous fresh and saltwater aquatic and atmospheric settings throughout the world (Farady 2019; Zhang et al. 2020). Microplastics can expose organisms and the broader environment to potentially harmful chemicals, especially plastic additives such as flame retardants, plasticizers, or dyes (Rochman et al. 2019), and to the microbial communities that may selectively colonize them, known as the plastisphere (Zettler et al. 2013; Amaral-Zettler et al. 2020). Like many pollutants, microplastics and their harmful chemical and microbial loads can be transferred up food chains (Chagnon et al. 2018). The scientific world is continuing to evaluate the exact extent, concentration, and impact of microplastics in our environment globally. If we are to reduce future inputs of microplastics in the environment, global and individual accountability is needed and science education plays a critical role in communicating reliable information about the extent, fate, and transport of microplastics in the environment (Raab and Bogner 2020). One challenge the scientific world is facing is that of measuring the concentration of microplastics in the hydrosphere, pedosphere (soils), biosphere, and the atmosphere. A priority for the educational community is to communicate the urgency of tackling microplastics pollution when this scientific field is itself changing rapidly.

The GLOBE Program

There are numerous theoretical foundations of science, technology, engineering, math (STEM) learning. In the context of this pilot study, STEM learning refers to providing in-school and out-of-school classroom environments that provide students with equitable experiences and multiple student-led opportunities to engage, explore, explain, elaborate, and evaluate scientific phenomena. Furthermore, effective STEM learning environments provide meaningful integration of STEM subjects, encourage collaboration, and provide students with authentic and realistic situations in which to engage with the STEM content (Glancy and Moore 2013).

The GLOBE Program is a formal and informal science program that provides a hands-on approach to science learning. Since 1995 GLOBE has provided students and the public worldwide with the opportunity to meaningfully contribute to our understanding of the Earth system and global environment by generating homogeneous data at a global scale. GLOBE gives teachers access to scientifically rigorous environmental monitoring protocols. Teachers, students, and citizens collect data in accordance with GLOBE Protocols and share them with the GLOBE community. The data collected helps validate scientific observations made by science agencies such as NASA and NOAA. In the GLOBE context, newly proposed protocols are evaluated to ensure currency of their educational and scientific monitoring “offer.” A draft of the Microplastics Monitoring Protocol (MMP) used in this project is available for public use. It is anticipated that within the next year this protocol will be submitted to GLOBE for approval as a protocol.

The MMP was devised by GLOBE Italy and Labter-CREA (S. Sutti) and Deakin University (A. Sutti, S. Robottom) in 2019. This protocol aims to incorporate best practice and approaches from similar scientific protocols, while enabling students and teachers to apply advanced scientific approaches using tools that may be available in schools. The MMP contains a teacher guide that summarizes key scientific concepts, contextualizes the issue and the protocol itself, and is accompanied by a database of hundreds of reference images (and a guide to recognizing microplastics under the microscope dichotomous key) (A. Sutti 2021). The draft MMP has been under teacher and student testing worldwide since 2020 and has benefitted from informed recommendations from over 300 participating teachers from 16 countries. During the first two years of testing, teachers tailored their students’ participation to study a locally relevant water body that aligned with their curriculum. Localized optimization of the educational experience included cross-curricular examples as well as science-class-only examples.

Microplastics Pacing Guide and the Pilot Study

The four-day pacing guide is designed to give teachers confidence, procedural standardization, and consistency in delivering scientific content. The pacing guide is also likely to facilitate incorporation of new content in time-sensitive settings, while providing sound scaffolding for incorporation of longer-term activities in more flexible curricula. The pacing guide also encourages broader participation in the school and its community and accelerates the uptake of new approaches and protocols that may be emerging at a pace that is higher than that of curriculum evolution. These aspects were included in this pilot study.

Three experienced GLOBE teachers expressed an eager interest in participating in the pilot study using the pacing guide for microplastics analysis and together they demonstrate its application for the first time within the context of the US curricula. A fifth-grade teacher sampled water from Old Mill Creek in Mill Valley, California. Another teacher sampled water from the Tidewater Boating Center in Oakland, California, for analysis with her seventh-grade students. A high school chemistry teacher from Sacramento guided his students in analyzing water from Jenkinson’s Lake in Pollock Pines, California. While all three piloting teachers are GLOBE-trained in performing hydrosphere protocols with their students, they were unfamiliar with investigating microplastics in local surface water samples. All three teachers were interested in being a part of the pilot study due to the recent elevation of microplastics in the news and their interest in bringing relevant STEM learning into their classrooms.

The microplastics pacing guide is designed to combine a student experience of an out-of-school GLOBE water quality investigation with in-school science content delivery and a formal microplastics lab. The pacing guide provides a connection between outdoor and indoor STEM learning experiences for students that concludes with a student storytelling opportunity whereby students share their cumulative STEM learning experiences through a poster presentation. The pacing guide consists of the following class periods, each lasting approximately 50 minutes:

Pacing guide overview

Day 1: Sink or Float Activity

  • How do we use plastics in our everyday life? Sink or Float Activity – Students place various plastics into sample water to determine whether they sink or float using a Claim, Evidence, Reasoning strategy. See Appendix for full lesson.

Day 2: Why Should We Care?

  • Microplastics and Science Content – Teacher-led targeted science content connecting grade-level topics with plastics/microplastics in the environment. See Appendix for overview and sample slides for fifth-grade, seventh-grade, and high school students.

Day 3: Investigating Microplastics

  • Investigating Microplastics Lab – Students filter water samples and evaluate the presence and types of microplastics. See Appendix for field guides, student worksheets, and full MMP.

Day 4: Storytelling - Putting It All Together

  • Students prepare storyboards of their STEM learning about microplastics using a poster-presentation format. See Appendix for storyboard template, sample, and link.

Extra Day (optional and encouraged)

  • Hydrosphere analysis was performed on water samples using the GLOBE Program Protocols. See Appendix for links to GLOBE hydrosphere protocols (including field guides, student worksheets) and learning activities.

Spring 2022 pilot study goals

The main goals of the pilot study were to:

  • Receive feedback from piloting teachers on their ability to implement a STEM learning pacing guide that includes both out-of-school field investigation and in-school science content delivery and formal microplastics lab.
  • Refine microplastics lab protocols, field guides, and instructional materials to include tailored grade-appropriate language.
  • Prepare a project-findings report to the GLOBE Implementation Office summarizing the feasibility of adding the MMP as an additional hydrosphere protocol to the GLOBE program.

Pacing guide activity details

Day 1 Activities – Sink or Float. All piloting teachers completed Day 1 activities within the estimated 50-minute time frame. There was evidence in the seventh-grade classroom that the student teams classified plastics as sinking and floating using a data table and were able to analyze the class data (Figure 1). It is important to note for this day that water samples (approximately 1000 ml) can be brought in from the previously completed field investigation event and used to determine whether the plastics sink or float in the water body that students previously investigated. Tap water (instead of field water samples) was used in the pilot study.


figure 1. seventh-Grade Class Sink or Float Data

Day 2 Activities – Content Connections. Teacher presentations for Day 2 clearly showed the connection between microplastics and Bay Area water bodies. Teachers reported that they were easily able to connect targeted science content to microplastics for their students. The fifth-grade teacher connected microplastics to using science solutions to protect the Earth’s resources and environment (5-ESS3-1) (NRC 2013). The seventh-grade teacher connected the microplastics pacing guide to the study of matter and its interactions (MS-PS1) using the health of local watersheds (NRC 2013). The eleventh-grade teacher connected microplastics to the study of the structure and properties of matter and chemical reactions (HS-PS1) (NRC 2013).

Day 3 Activities – Microplastics Lab. All three grade levels completed Day 3 activities with the support of the guest scientists from the San Francisco Bay National Estuarine Research Reserve and University of California Berkeley. Guest scientists guided students in both the water filtration and microscopy portions of the lab in less than 60 minutes. More time is preferred for the microscopy portion of the lab. Guest scientists are available virtually and in-person through the GLOBE International STEM Network.

Each class was divided into groups of two to four students. All students participated in the field activities. Students with special needs were grouped with mainstream students. All students had a responsibility within their group to ensure equal participation. Once students finished filtering the sample water, they removed the filter paper and placed it on a petri dish viewed under a traditional school microscope. Using four N/E/S/W quadrants on the filter paper, students identified what they saw using a dichotomous guide. Students could discern between abiotic (microplastics) and biotic (plankton and algae) specimens. A few students initially mistook the filter paper grid lines for microplastics. Most students were inexperienced with using microscopes and questioned their ability to identify the true category of microplastics, but with a bit more practice and time, they likely could have completed their identifications with confidence (Figure 2). All students were asked to draw the microplastics they saw, which helped them stay engaged with their STEM learning (Figure 3).

Figure 2. 11th-Grade Student Photo of Microplastics
microplastics image
Figure 3. fifth-grade Student Drawing of Microplastics
student drawing

Day 4 Activities. Unfortunately, none of the three grade levels completed this activity in the pacing guide, which was for each student team to create a STEM-learning poster about microplastics. All teachers expressed an interest in doing the poster but cited the need for more class time, which they didn’t have. Teachers explained that this summative activity required more time to frame with their students since they had never incorporated a learning poster into their curricula.

Extra Day Activities. All three piloting teachers opted to include GLOBE Protocols into the pacing guide. Students tested and analyzed water samples for pH, alkalinity, dissolved oxygen, nitrates, temperature, and transparency. Temperature, dissolved oxygen, and transparency protocols were performed at the sample collection site.


Overall, a pacing guide on microplastics, following complementary field investigation of local surface waters using GLOBE hydrosphere protocols, provides an opportunity to link California science standards to local (community) real-world problems. This combination of out-of-school and in-school STEM learning serves as an example of how to engage students in environmental justice by exploring water quality in local water bodies to give students a local reference point for their learning. It also encourages students to provide possible explanations of poor water quality due to the presence of microplastics in water, elaborate on the cause-and-effect relationship microplastics have with biotic and abiotic factors in the water, and evaluate possible solutions to environmental impacts resulting from the use of plastics.

One teacher observed, “They [students] really saw the applicability of microplastics in their lives. They researched fun facts such as how much plastics they use … in a week and what happens to it when they throw it away.” “It [the pacing guide on microplastics] was very helpful.” “I want to see if there’s a way for my students to get more tools to test [water in] our neighborhood park.” According to the WestEd/UCB 2022 annual program report to NASA for the GLOBE Mission Earth Program, “A bright spot that sparked student participation was the new microplastics protocol that… teachers piloted with their … students. The teachers who piloted this new protocol said it was accessible, popular, and engaging. Students participated in filtering water and identifying and describing microplastics from the local watershed using filtration pumps, worksheets, and light microscopes. Students and teachers valued the opportunity to collaborate with scientists.

The feedback and information gathered from the teachers who applied the pacing guide was consistent with that provided by teachers during the 2020–2022 international MMP trial, where teachers introduced the MMP into their local STEM or cross-discipline curricula using a variety of timelines (in some cases across seven months).

Some implementations and adaptations, which were independently developed by teachers in this study (e.g., drawing images of observed microplastics), also match effective solutions developed by teachers in the global trial. Similarity was also observed in the difficulties encountered by students approaching microscope observations and interpreting local evidence-based results that challenge common beliefs (e.g., plastics float). This indicates that the microplastics pacing guide is a highly relevant tool from the educational and pedagogical perspective, as it allows teachers to not only rapidly and effectively guide delivery of new and current educational content for the students in their classes, but it also provides STEM and STEM-education researchers a rapid method to gather reliable data on the educational and scientific experience by teachers and students, and to rapidly prototype and introduce new solutions to local challenges.

The MMP and the pacing guide together are a tool that enables students to make connections to Earth system science, system thinking, cause-and-effect relationships, and identifying patterns in scientific data. The MMP provides key lab skills for students and answers the “why do I need to know this” question students often have. Students can determine the amount of microplastics in their local water body and they can use those findings as standardized data suitable for submission and sharing—and comparison with analyses of locally significant water bodies by students located elsewhere around the world. The efforts of these teachers to contextualize the MMP within the US educational setting demonstrate both the protocol’s suitability and the importance of teachers’ informed participation to guide their students.

Microplastics findings can be compared to (and correlated with) water quality indicators such as transparency, pH, and temperature. From their out-of-school field testing experience and their in-school laboratory investigation, students can share their story about their STEM learning journey of relating microplastics in surface waters to the protection of Earth’s resources and environment, the study of matter and its interactions, and/or the processes of chemical reactions. Data collection and analysis from these experiences can be used to support data literacy skills such as data organization, visualization, analysis, interpretation, and storytelling. Data gathered in these experiences is also directly supporting international research efforts toward establishing the extent of microplastics pollution in surface waters, especially in small water bodies such as bays, rivers, and lakes. The study of microplastics in the environment provides a very promising platform for data-rich STEM learning. The pacing guide is a tool that catalyzes students’ and teachers’ curiosity and lowers local barriers to approaching otherwise highly complex and rapidly evolving STEM subjects.

Recommendations for Teacher Implementation

  1. The microplastics investigation can be paired with related science content and phenomena such as, but not limited to: Biology—aquatic biology, ecosystem balance, hydrology cycle, biomagnification, bioaccumulation; Chemistry—acids and bases, covalent bonding, carbon compounds and composition, chemical reactions; Earth/Environmental Science—systems thinking, waste fate and transport; and Physics—density, Earth’s energy budget.
  2. Prior to starting the microplastics investigation, ensure students are familiar with using a dichotomous key. This can be accomplished by using slides prepared with reference abiotic materials (plastic pieces such as glitter, textile fibers of different types, etc.). Once students have identified the plastic using the key, ask them to compare/contrast their findings to the photos in the microscopy guide.
  3. Many students (and teachers) are unfamiliar with student storytelling as a pedagogical practice. Digital storytelling is one of the latest pedagogical approaches that can engage K–12 learners in computational thinking. Prior to introducing the microplastics investigation, give students an opportunity to use storyboards to demonstrate what they have learned. For the last day of the pacing guide, post the student storytelling poster on a Google Slide and have students make a copy of the slide for their own storytelling. The poster mimics scientific posters by STEM professionals and has separate panels to guide students through their storytelling.
  4. Classrooms accommodating students with special needs will need to group students based on abilities. Both the filtration and microscopy portions of the investigation can be completed by all students, regardless of their abilities. For example, a special needs student can take their turn pulling the plunger during water filtration. Also, a special needs student can verify microscope identification of microplastics, draw what they see in the microscope, or be responsible for participating in clean-up activities.
  5. While most schools have standard microscopes for the microplastics investigation, few have the necessary equipment to filter water samples. An equipment list is included at the end of the Appendix. School financial support or fundraising is recommended.

For more about the GLOBE Program, visit The SF Bay NERR and WestEd/UCB collaboration is a part of a wider-reaching Earth System Science collaborative called California Strong. This collaborative consists of a group of scientists, researchers, outreach specialists, and educators who work together to spread Earth system science initiatives throughout California using the tools and resources of the GLOBE Program. The WestEd/UCB partnership primarily operates thanks to a grant from the National Aeronautics and Space Administration (NASA) awarded to GLOBE Mission Earth (#NNX16AC54A) This project was supported by GLOBE Italia, Labter-CREA MN, and Associazione GLOBE Italia APS, GLOBE Europe-Eurasia Region Coordination Office, and partly funded by the Australian Research Council Research Hub for Future Fibers (IH210100023) and Deakin University.

Tracy Ostrom is a former high school science educator and environmental scientist serving as GLOBE Mentor Trainer and Northern California GLOBE Coordinator at the University of California Berkeley, Department of Chemistry and Atmospheric Sciences in Berkeley, California and a PhD student in the Graduate School of Education at the University of California Davis in Davis, California. Matt Ferner is with San Francisco State University and is the Research Director at the San Francisco Bay National Estuarine Research Reserve in San Francisco. Alessandra Sutti is an Associate Professor and Team Leader at Deakin University's Institute for Frontier Materials in Geelong, Victoria, Australia. Stuart Robottom is a Manager at Deakin University's Institute for Intelligent Systems Research and Innovation in Geelong, Victoria, Australia. Sandro Sutti is the GLOBE Italy Country Coordinator and the Scientific Coordinator at the Territorial Laboratory-Reference Centre for Environmental Education, LabTer-CREA, in Mantova, Italy.


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