Numerous reports suggest an increase in white shark encounters* in the United States in recent years and the public is worried.
*Encounters include sightings and census estimates, as well as physical interactions between humans and sharks.
Develop and use a model to show how device function is influenced by the properties of waves.
Devices that emit different types of waves will perform differently in air, without air, and when submerged in water.
Click here for NGSS, CCSS (ELA), and California ELD standards.
Prior to this, students applied understanding of how sharks have electrosensitivity to components of tracking devices. In learning this, students explored magnetic fields, currents, and the relationship between the two.
This lesson provides students the opportunity to conduct an investigation to learn more about the various types of devices used to track white sharks (those that transmit and those that receive information/data) and the influence of different mediums on the performance of the wave used by those devices. Students build iterations of a model, based on evidence, to show their understanding of both observable and unobservable phenomena and how differences in a system impact the phenomena. They use this model to show complex and microscopic structures and systems and visualize how their functions depend on the composition and relationship among parts and properties of different materials. The purpose of this lesson is to introduce waves in a context that is motivating for students, giving them partial understanding of PS4.A (a sound wave needs a medium through which it is transmitted). Ideally, students would enter this learning sequence having a foundation in wave properties as they will be able to apply that knowledge to find deeper understanding here.
In the next lesson, students will explore the concept that digital signals are more reliable than analog and thus used in tracking devices.
Throughout the lesson, a flag () denotes formative assessment opportunities where you may change instruction in response to students’ level of understanding and making sense of phenomena.
Part I | 45 minutes | Engage |
Part II | 70 minutes | Explore |
Part III | 20 minutes | Explain |
Develop and use a model to show how energy is transmitted through different mediums.
By the end of 8th grade, models should include particles (in this case, air particles). If you notice only a few models that include air particles, have students share models with peers and encourage another revision. If this doesn’t self-correct student models, ask the class to direct you (at a white board in the front of the room) how to model the phenomenon. Only draw/label what students direct you to; ask questions about what they are asking you to do and why. If no one mentions air, ask what is in between the spoon and the ear and how it can be represented in the model. The class should come to an agreement of how to show air particles (usually small circles, O) and how they should be spaced since air is a gas. If the idea of vibration has emerged, ask what that vibration would do to the air particles and how that could be shown in the model. (Many students will agree that a vibrating particle can be drawn as “O”, as opposed to non-vibrating, O.) This particle idea is important to understand moving on to the idea of sound moving under water. The idea of energy should also emerge as students have previously built this idea in prior grades. Many students tend to agree to show energy moving as a directional arrow.
This note is intended to help facilitate student sensemaking of phenomena. Once students are describing the role of the spoons and noticing the vibration, then it’s appropriate to encourage students to use the phrase, vibrating source. The same is true for their ears; once they realize the ear has a role in detecting the vibration, then it’s appropriate to encourage use of the word receiver. If students have a hard time internalizing that the spoons vibrate, model the same phenomenon with a ruler on the edge of the desk that gets tapped; kids will readily notice the vibration and can apply that understanding to the spoons. Showing a video clip of a guitar string can also help illustrate the concept (things that make sound vibrate). In addition, students may forget the importance of particles in their model. If you don’t see students representing air or water in their models, ask them to recall what air is made of and what water is made of and how they could show that in their model. Then ask how they think the energy from the vibration gets from the source to the receiver. A simple example of having students line up, shoulder-to-shoulder, feet “glued” into place, and gently pushing on the outside shoulder of student #1 (towards the shoulders of other students) would demonstrate how energy from one end would go through particles (students) to the other end, showing the particles moving but not dislocated from their position.
Additionally, when students are diagramming their models of the spoons tapping in the water, it is useful for this model–and for other models within future lessons–to have the class come to consensus about what symbols can represent the “unobservable mechanisms” involved for both matter and energy. For example, students may agree that air and water particles are drawn as circles (perhaps color coded differently) and sound waves are drawn as half circle lines. A consensus on these symbols help students understand the ideas being expressed in a model diagram when groups are sharing their thoughts with others. If different groups use a variety of different icons/symbols to express their thinking, their ideas are more likely to get lost in translation.
Caution about sound: The intent of considering sound (acoustic) wave use in tracking devices here is to help explain why scientists use different types of waves in tracking devices. Students will eventually be able to conclude that sound needs a medium to travel, but differences between salt water and fresh water will only be explained by ideas around it being harder to move in salt water than fresh water; a more complete explanation involving speed of the wave is reserved for high school.
As students share and discuss as a class, encourage them to use discussion norms such as wait time, encouraging others to say more, asking for evidence, paraphrasing or repeating, adding on, etc.
Responses could include the following:
For students struggling with the modeling process, suggest they add a story of what is happening to accompany the work they are able to do (like a narrative). If able, encourage them to use this story to inspire ideas of things they can add to the model and vice versa.
Develop and use a model to show differences in how energy is transmitted through different mediums.
Ask students to record questions they have during the video about how the tag is working. Next, ask, “If a shark has a device like a fitness tracker and camera, how do researchers get the video feed and the information (data) from this tag or one like REMUS?” Discussion should involve recognizing this data needing to move through salt water, between tag and receiver. Ask, “How does the transmission of that informational data (energy) change when it’s moving in the water vs. the air?” and discuss.
This is intended to be a faster investigation (Explore) for students and thus, how students plan their investigation has simple requirements to expedite the work. Thinking of the spoons or a device like a timer/buzzer that emits sound, the sound should be somewhat harder to hear when the device is submerged in fresh water or salt water, but still audible. Radio waves, however, are disrupted by the ions in salt water. A radio submerged in salt water won’t be able to receive the radio signal (signal will be “cut” when surrounded by at least a foot of salt water on all sides), and therefore students won’t be able to hear the radio. Making sure students have access to a device that makes sound but doesn’t use radio waves will help avoid confusion about the radio receiving a signal vs. producing sound. Quality zip-top bags are needed to seal devices and protect them from water damage.
After a group can verify that all group members are ready (each has a description and prediction), students from the group may begin testing and recording results, small models, and explanations.
Throughout this process, encourage use of the 8.1.H2: Scientist Communication Survival Kit (from Lesson 8.1: Shark Encounters) as this helps to ensure equitable conversations and contributions from students. Consider providing sentence frames for students who need literacy support, or allowing these students to work in pairs writing portions together; later you can make a copy of the work completed for the other student to put into their Science Notebook. Alternatively, allow students to do this work in their native language.
Radio waves aren’t a specific feature of the DCI being addressed, but do belong to the same type of energy as light. In this case, however, radio waves are different waves than light waves (they have a longer wavelength) but they behave in the exact same manner (perpendicular motion of particles but the energy has an overall forward movement). It may be useful to let students know they are the same type of wave and to consider how the structure of the wave impacts its function. (If students ask, let them test light sources in the water tanks and compare them to the AM/FM radio.) In both cases, radio/light and sound, energy of the wave moves forward in a repeating pattern that is predictable and has a different impact on the particles in the medium it moves through:
To help students understand the differences, once again, have a few students stand in a “home” position: standing in a line, shoulder to shoulder, arms locked at elbow, feet “glued” into place. Gently push on the outside shoulder of student number 1 (towards the shoulders of other students) to demonstrate sound (movement going left and right through “particles” to the other end, showing the particles moving but not dislocated from their position). In the case of radio and light, have students stand in the home position again, but this time have student number 1 bend over and stand back up, this pulls student number 2 (and onward) down and up simulating the movement of particles going up and down.
Then ask how they think the energy from the vibration gets from the source to the receiver. A simple example of having students line up, shoulder-to-shoulder, feet “glued” into place, and gently pushing on the outside shoulder of student number 1 (towards the shoulders of other students) would demonstrate how energy from one end would go through particles (students) to the other end, showing the particles moving but not dislocated from their position.
It is expected that students would engage in a previous learning sequence prior to this one where they develop understanding of this aspect of PS4.A–a simple wave has a repeating pattern with a specific wavelength, frequency, and amplitude–in more depth through the SEP of mathematical and computational thinking (although some teachers may choose to spend that time now). This lesson will provide opportunities for students to apply that knowledge (although we have left out the terms wavelength, frequency, and amplitude to allow flexibility for teachers who may wish to address it later). As an aside, students do begin exploring a related DCI in 4th grade and may recall some of that information.
To help guide students in creating grade level appropriate models, give students the rubric to help guide work, 8.6.H1: Final Wave Model and Explanation Rubric. Once again, for those needing support, allow for stories/narrative to be used.
8.6.R1: Shark Lab Tracking Devices and 8.6.R2: Shark Lab Model are for your reference. 8.6.R2: Shark Lab Model, in particular, is NOT intended for students to copy, but provided in case it would benefit your discussions with students.
Ask students to collaborate as a group to update their group consensus model to show new understanding. If time warrants ( and especially if models could benefit from some editing or clarification), ask groups to move around the room to review the models of two other groups and provide sticky-note feedback to each group’s consensus model:
Students returning to their group are asked to make at least two changes to their group consensus model based on peer feedback.
Develop and use a model to show differences in how energy is transmitted through different mediums.
Develop and use a model to show how device function is influenced by the properties of waves.
The activity in Step 15 is intentionally open-ended to allow for students to freely show knowledge. For students that need more direction, consider adding more specificity such as: How do researchers on shore or on a boat get informational data (energy) from a tag or tracking device that is under the surface of the ocean, and what is this informational data (energy)?, or What types of informational data can be collected?, or Imagine two different receivers are being used, one below the surface of the ocean and one above; what type of wave/energy is most advantageous for each circumstance and why? For students that are highly motivated, ask them to extend their model to compare how the human ear detects sound to how a white shark uses their ampullae of Lorenzini to detect electric fields. How might pressure and/or temperature changes in the water affect the detection process? How do the ampullae of Lorenzini compare to the tympanic membrane in the human ear? How do pressure and temperature affect how humans detect sound?
For classes where students will struggle with searching for information on SPOT and PAT tags, consider archiving a few good resources in a shareable document for students to quickly link to. If students tend to disengage easily, have at least four resources ready and jigsaw the task as a group where students know they will be responsible for teaching the other members of their group about their research.
When showing short videos, it’s often helpful to students to watch the video once to get a sense of the purpose. Showing the video a second (and sometimes third time) allows students to focus on important details that can be recorded in their Science Notebooks and discussed.
During the investigation with the salt water tank, allow each group the chance to use the salt water tank once they have completed their Science Notebook work. (Avoid doing this as a class demo.) This will motivate students to complete their work.
By seating students in groups (groups of 4 work well) and encouraging regular conversation, students have time to interact more with content and naturally help those that need more support. Use of 8.1.H2: Scientist Communication Survival Kit helps to make sure that students who don’t feel comfortable sharing (often because of language, literacy level, uncertainty of content knowledge, etc.) are prompted to do so in a supportive way.
Use of a sense-making Science Notebook supports student language development, conceptual development, and metacognition. Students should be prompted to use their Science Notebook for
In this lesson, students are asked to create a plan for testing in their Science Notebook. Students often come up with really great ideas for organizing; however, some can struggle. Keeping a “teacher notebook” that provides an example for how to organize information can help. Make the teacher notebook available for any student who is apprehensive about organizing their own. This can encourage independence without over scaffolding.
Consider providing sentence frames for low literacy and second language learners. The use of graphic organizers can help struggling students manage Science Notebook work.
CSULB Shark Lab (2017, July 18). NGSS Learning Sequence: Jawsome. Retrieved from https://youtu.be/CajgBDBOkLk
NBC News/Today (2017, May 18). Shark sightings in shallow water have experts racing to learn why. Retrieved from https://www.nbcnews.com/video/shark-sightings-in-shallow-water-have-experts-racingto-learn-why-947022915732
QuantumBoffin (2010, February 1). Bell in a Bell Jar. Retrieved from https://www.youtube.com/watch?v=ce7AMJdq0Gw
Woods Hole Oceanographic Inst. (2014, July 19). REMUS SharkCam: The Hunter and the Hunted. Vimeo, retrieved from https://vimeo.com/101165012