Teachers and families across the country are facing a new reality of providing opportunities for students to do science through distance and home learning. The Daily Do is one of the ways NSTA is supporting teachers and families with this endeavor. Each weekday, NSTA will share a sensemaking task teachers and families can use to engage their students in authentic, relevant science learning. We encourage families to make time for family science learning (science is a social process!) and are dedicated to helping students and their families find balance between learning science and the day-to-day responsibilities they have to stay healthy and safe.
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Sensemaking is actively trying to figure out how the world works (science) or how to design solutions to problems (engineering). Students do science and engineering through the science and engineering practices. Engaging in these practices necessitates students be part of a learning community to be able to share ideas, evaluate competing ideas, give and receive critique, and reach consensus. Whether this community of learners is made up of classmates or family members, students and adults build and refine science and engineering knowledge together.
Niagara Falls is one of the great natural wonders of the world. However, the falls have not always looked the way they do now. In fact, even the location of the three falls that make up Niagara Falls - American, Bridal Veil, and Horseshoe Falls - have changed! In today’s task, Why is Niagara Falls moving?, students analyze and interpret data and use the thinking tool of cause and effect to help explain why Niagara Falls has changed location and shape over time.
Tell students you have a puzzling phenomenon to share. Ask them to create a Notice and Wonder t-chart in their science notebooks. Share the photos of Niagara Falls with students. You might show their location on a map. Be sure to point out that the photos are taken from opposite directions; the Niagara River flows north. Give them independent thinking time (Alone Zone) to make and record observations in the Notice column and to note any questions they have under Wonder.
Have students share what they Notice and Wonder with their small groups. What observations do they have in common with their group members? Did anyone notice something that no one else in the group observed? Next, ask student groups to develop an initial model to explain why Niagara Falls has moved over time.
As you move around the room, you might ask some of the following questions to deepen students' thinking about the explanation:
Create a class consensus model. Begin by asking students to point out the common components between the group models. While developing a class consensus model, make sure students agree to the addition of each component and their interactions. If students do not agree on a component or interaction represented, ask if you can use a question mark or draw with a dotted line to represent things the class is unsure of or doesn't agree on.
Provide students time to review their questions and add to or revise them based on the class model. Create a physical or digital space for students to post their questions. You might proceed by asking one student to share the first question. Then, ask students to raise their hand if they feel their question is connected to the one that has just been presented. These students can then share and post their questions in the same area of the driving question board. Once all related questions have been posted, ask a student to volunteer to share the next question. This process allows for all students to share questions and easy organization /categorization of questions on the driving question board.
Why does the shape of the falls keep changing over the years?
Why do the falls change (move) more sometimes than others?
Will the falls keep moving forever? (End up in another state)
Does the US-Canada border move with the falls?
Do the falls move a little at a time or do big chunks fall off at once?
Is there a way to keep Niagara Falls from moving?
Additional Guidance: As students work in small groups, listen for students using prior knowledge and personal experience to explain the phenomenon. Also listen for common misconceptions. At this point in the task, it is important to resist the urge to correct misconceptions! Instead, allow students to build on/change their own thinking as they move through the task.
Share the following quote with students:
According to the International Joint Commission, the movement of Niagara Falls is more rapid when it is in a V-notch shape than when it is spread out.
Ask students to turn to a partner and share ideas about why the shape of the falls might affect their movement. Push their thinking further by asking if there are factors besides shape that might play a role in the rate Niagara Falls moves. Remind students where Niagara Falls are located. You might even show them the images below. Consider moving from partners to small groups. This is a great opportunity for students to discuss and compare idea.
Bring students back together and ask them to share factors that might affect the rate the falls moves. Students might share (with suggested follow up questions)
Engage students in an investigation utilizing a stream table or a simple set-up of sand and water. You might ask half the class to investigate how shape affects the rate of falls movement and the other half investigate how the amount of water flowing affects the rate of movement.
Provide an opportunity for student groups to share their data with the class. Ask students to identify patterns in both "shape" data and "flow" data. You might revisit the class consensus model and ask students to discuss in their small groups if they would add to or change the model. Bring the class back together and ask small groups to share their thinking. Do we still need this question mark? Can we make these lines solid now? Are there places we need new question marks/dashed lines?
Additional Guidance: Make sure to discuss the limitations of the stream table model. The stream table uses sand, which represents rock that has already been weathered. The falls need to be weathered before erosion occurs. Also consider prompting students to think about the difference in water being funneled into a narrow funnel versus flowing over a wide area to figure out why erosion would be faster at a ‘V’ shape versus a ‘U’ shape. If stream tables are not available consider showing a video of a stream table investigation like this Erosion lab video (see 4:25 - 5:00). Have students make predictions before showing the video, drawing on prior knowledge about/experience with erosion.
Note: Both weathering and erosion need to happen for the falls to move. To further consider the role of weathering in the movement of Niagara Falls, you might have students work through a series of short weathering activities like the ones described in this weathering and erosion lesson from understandingscience.org.
Introduce three data sets to students, Actual recession rate of Horseshoe Falls and American Falls over differing time periods, Historical changes in flow discharge over Niagara Falls, and Historical changes in lip length of Horseshoe Falls, and ask them to look for patterns in each data set and patterns between the data sets. Encourage students to compare both data sets with the shapes of the two falls (see pictures below). Ask students to share what they notice, first with a partner and then with the class.
Students will likely notice the following patterns:
Guidance: You may need to take time with middle school students to make sense of the Actual recession rate data table, especially the units (meters per year or meters/year). You might ask them to compare the size of the data intervals (Duration) between Horseshoe and American Falls. Do they think American Falls ever receded as fast as Horseshoe Falls? Why or why not?
Provide students with this additional piece of data:
According to niagaraparks.com, the recession rate has been greatly reduced due to flow control and diversion of water for hydro-power generation. Its current rate of erosion (recession) is estimated as 0.3 meters per year and could possibly be reduced to 0.3 meters per 10 years.
Ask students to think back to the class ideas about factors that affect the rate of erosion (recession). Could any of the other factors explain why the recession rate has decreased over time? Tell students to turn and talk with a partner to share ideas. Ask them to consider what additional data they might need to provide evidence to support their ideas. Students might say the amount of rainfall/snowfall might have decreased over time; they could look at historic weather data. Other students might wonder if people are using the water for drinking or irrigation. Researching sources of drinking water for towns along the Niagara River would provide data to support or refute this idea.
Tell students to return to their small groups and identify components, interactions and/or science ideas the class should add to/change on the class consensus model. Bring the class back together and ask small groups to share their thinking. Do we still need this question mark? Can we make these lines solid now? Are there places we need new question marks/dashed lines?
Refer students back to the driving question board. Ask them to identify question they can now answer or partially answer. Based on remaining question marks/dashed lines on the class consensus model, ask "What do you think we should investigate next?"
NSTA has created a Why is Niagara Falls moving? collection of resources to support teachers and families using this task. If you're an NSTA member, you can add this collection to your library by clicking Add to My Library (near top of page).
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