Setting the Context: What Are Waves?

The ideal kickoff for this unit is a trip to a real coastline, to observe the behavior and impact of waves. With the teachers in the professional development institute, we were able to start in just this way, sitting in silence on a beach, observing waves, and recording ideas in science journals with the prompts “I notice” and “I wonder.” In the camp and school settings, the children traveled to a shoreline at the end of the unit rather than the beginning, so we built initial knowledge of waves through recall of past experiences, video examples, and exploration of the waves in the simple wave tanks we would be using in our design challenges (large plastic bins fitted with plexiglass “wave makers” the width of the bin, see Supplemental Resources for safety guidelines). They practiced making and measuring waves of different sizes in the bins, which allowed them to observe wave action and to practice making consistent waves, a skill they would need for testing in later challenges. The children also recorded “I notice” and “I wonder” responses in their notebooks, shared them with partners, and used them to engage in a whole-group discussion of what we knew and did not know about the motion, cause, and impacts of waves. This opening lesson is particularly important in creating an equitable learning environment, as students may come to this unit with a wide range of prior experience. In our fourth-grade class, given our proximity to the ocean, all students had spent time at the shore and were able to share firsthand knowledge, but in classes with a wider range of experience, practice making waves in the wave tanks and observe video examples to build initial understanding of the phenomenon.

After our initial exploration of waves and their properties, we turned to the question of how scientists measure and track waves, weather, and other features of a changing ocean. This led to our first design challenge, designing a model ocean observing station.

Design Challenge 1: Ocean Observing Station

This design challenge was inspired by an article in Science Scope (Love and Deck 2015) that described a challenge for middle school students to design, build, and test ocean monitoring platforms. We modified this challenge to fit the elementary school context and content, focusing on how scientists design monitoring stations to withstand ocean conditions. We began this session with a gallery walk of photos of scientific buoys used to monitor ocean conditions. We noted similarities and differences in design and discussed how different features might help the buoys both survive ocean conditions and accurately collect data about the water, waves, and weather. We then presented student teams with the design challenge specifications (see Supplemental Resources).

Teams of three received a resealable bag of sample materials, which they could handle and test in the wave tank as they planned their design. By providing only a sample of the materials, we allowed students to explore the properties that might make an effective station while encouraging them to focus on creating a design before they actually started building. We asked students to spend 10 minutes working independently “dreaming and drawing” about possible effective designs. They then worked as a team to make an initial plan in the form of a labeled drawing and supply list. This plan needed to receive approval from the “chief engineer” (the teacher) before the group could gather materials from the supply table and begin building their first model. As groups completed their first iterations, they tested them in the wave tank under three conditions: 1 cm, 2 cm, and 4 cm waves. The whole class stopped to observe and discuss each of these tests, noting what design features seemed most effective and what needed improvement.

Because students had several ways to engage in planning and design, as well as ample time, prior to building, many of their first attempts met the basic specifications of the project. This allowed them to focus their second round of refining and re-building on “fine tuning” their designs, for instance making them more materials efficient or sturdy during even higher waves. This correlates to what engineers most typically do: Significant planning and discussion generally happens before using costly materials to test their ideas!

At the end of this activity, each child received a photo of their most successful design, which they glued into their science notebook. They used this as a prompt for reflective journaling on what they had learned about ocean monitoring, waves, and engineering design. Children also engaged in a discussion around why scientists would monitor the ocean and what specific issues scientists in our local area might need to know. In both the camp and classroom settings, children brought up monitoring ocean life, reducing pollution, and ideas about how weather and oceans interact. The teacher then asked children to return to the idea of waves and how scientists might use their knowledge of waves to study shorelines. This led to the second investigation and engineering challenge, zooming in on one strategy for mitigating the impact of waves on shorelines.

Design Challenge 2: Comparing and Improving Artificial Oyster Reefs

An exciting development in shoreline management is the increasing use of nature-based structures to protect and maintain shorelines. Traditionally, structures such as seawalls have protected vulnerable coastal communities, at great cost to natural habitats. More recently, scientists and engineers have focused on ways to restore natural shoreline protectors, including marshlands and reefs, as part of communities’ coastal management plans (SAGE 2015; see Sidebar). We introduced learners to these ideas through a video on living shorelines. We then focused on one element of living shorelines, the restoration of oyster habitats (see Online Resources). Scientists have built and tested a variety of artificial oyster reefs to grow and restore native oyster populations, a key element of shoreline protection in our local area. After a read-aloud and discussion of an article about local living shoreline projects (Greene 2014), we did another gallery walk, this time of different artificial reef designs that scientists have tested in different near-shoreline settings (See Latta and Boyer 2012 for photos of current artificial reef designs).

Our oyster reef design challenge had two phases: (1) each team replicated one of the existing designs, so that we could measure how effectively the design attenuated (reduced the force of) the waves and (2) teams then used the data from the initial tests to propose and test their own designs of artificial oyster reefs. We used a series of notebooking prompts (see Supplemental Resources) to focus groups on specific phases of this engineering process: evaluating existing models, identifying areas for improvement, designing and testing new models, and using data from testing to determine the effectiveness of a design and again identify ways to improve outcomes.

As we focused this second challenge more closely on analysis of quantitative data, the students found that gathering and interpreting reliable data from a model posed some challenges. We found that children needed to spend quite a bit of time working with the wave tanks to agree on a fair way to produce waves of different heights and to accurately measure the size of the wave before and after it encountered the artificial reef models. Calculating wave attenuation led to an extended discussion in which the children initially struggled to determine what the numbers meant and whether a higher or lower number indicated greater success (we used the simple ratio: attenuation = wave height before/wave height after). We should note that the concept of wave attenuation is beyond what is included in the NGSS standards at the elementary level. However, we found this simplified measure of change to be accessible to children and a useful way for them to quantify the impact of their reef models. We took the pride they showed in being able to explain how waves were measured (after their initial struggle) as a positive sign of building stronger identities as doers of science and engineering.

After analyzing data from all groups, teams had the opportunity to reflect upon and improve their designs. To assist with this, they read and discussed an additional article about how local scientists were designing and testing artificial reefs (Latta and Boyer 2012). Our intent here was to facilitate students’ consideration of evidence from multiple sources. One unintended consequence was that some groups decided their revised design should imitate as closely as possible the photos from the article and seemed to feel uncomfortable in proposing other possible designs. In future teaching, we would like to continue to consider the balance between encouraging innovative design and the important role of replicating and re-testing findings from other scientists.

Design Challenge 3: Living Shoreline Models

The final design challenge involved student teams synthesizing their knowledge and results thus far to design and test models of living shorelines that could effectively protect coastal communities from erosion and storm surges. To build content knowledge and seed ideas, we first gathered information about living shorelines from text and videos (see Resources) and made a list of features of living shorelines discussed in the video (such as: pliable, provides habitat for many living things, and layers of protection: oyster reefs, rooted plants, floating plants). The class then took a “tour” of available materials with which to build models of living shorelines, and we discussed the properties of the non-natural materials available for building, such as waterproof clay, plastic plants, and pipe cleaners, to decide which natural materials these supplies could represent.

We repeated the process of individual “dreaming and drawing” followed by collaborative written designs in teams of three. This time, rather than testing as groups finished, there was a standard time limit (30 minutes to plan, 45 minutes to build), and then we tested all of the models one after another, again collecting data on wave attenuation. Because of time and material constraints, rather than re-do the designs, all of which were at least moderately successful at attenuating waves, we asked children to first write reflections of what had worked well and what did not work as expected. They then drew plans for how scientists and engineers might use the results of their model testing to design real living shorelines. Their final activity, which served as a summative assessment (see Supplemental Resources), was a detailed drawing of their plan for a living shoreline in a nearby community and a written explanation of how information from scientists and from students’ design challenges informed their plan and why they thought it would work.

Final Thoughts

Our goal was to integrate the engineering design process into locally relevant content. Each of the design challenges required students to acquire content knowledge about the shoreline’s interaction with waves and to use their understanding in increasingly complex ways. Situating these challenges in a context that is of immediate and visible importance to our own community helped learners not only better understand engineering and ocean science but also see the importance of these fields to their everyday lives. ●

Supplemental Resources

Download safety guidelines, design brief, notebooking prompts, and assessment at https://bit.ly/3vhawt5.

Online Resources

Living Shorelines and Eelgrass

https://www.youtube.com/watch?v=mpaZdRP4vhM

Oyster reef video 1

https://www.youtube.com/watch?v=PbFQ5EndLso

Oyster reef video 2

http://reefinnovations.com/services/ecosystem-restoration/living-shoreline-reef-balls-are-being-used-across-the-coast