Sponsored Content NBC News Learn is a former division of NBC News ‐ distributing the journalism and storytelling of NBC News to students in the classroom, at home, and in the community. Physics of Figure Skating – Inquiry Guide (Grades 4 – 12) May 29, 2020 | 38 minutes, 47 seconds read This document is a companion piece to video titled Physics of Figure Skating and is intended as a resource for educators. Background and Planning Information About the Video Physics of Figure Skating discusses the important concepts of center of mass and projectile motion in figure skating. Featured athletes are Olympic medalist and former world champion, Evan Lysacek, and Ashley Wagner and Gracie Gold, who will be competing at Sochi as first- time Olympians. Also featured is Brad Orr of the Physics Department at the University of Michigan. The video points out that a skater’s center of mass must remain above the point where the skates contact the ice. The video also explains that when the skater is airborne (and thus described as a projectile), the center of mass moves in a parabolic path, because of the independence of the horizontal and vertical parts of this motion. The horizontal component of the velocity is constant, while only the vertical part is affected by gravity. 0:00 0:14 Series opening 0:15 0:50 Introducing Lysacek, Wagner, and Gold 0:51 1:04 Making figure skating look effortless requires an understanding of physics 1:05 1:40 Introducing Orr and center of mass 1:41 1:56 Finding the center of mass of a figure skater and why it is unstable 1:57 2:35 Importance of keeping center of mass above point of support 2:36 3:42 Projectile motion and figure skating 3:43 4:28 Demonstration of importance of vertical and horizontal motion 4:29 4:55 Summary 4:56 5:08 Closing credits Language Support To aid those with limited English proficiency or others who need help focusing on the video, click the Transcript tab on the side of the video window, then copy and paste the text into a document for student reference. Next Generation Science Standards The following inquiry investigations could be part of a summative assessment for these performance expectations. See NGSS documents for additional related Common Core State Standards for ELA/Literacy and Mathematics. Motions and Stability: Forces and Interactions MS-PS2-1 Apply Newton’s Third Law to design a solution to a problem involving the motion of two colliding objects. MS-PS2-2 Plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object. Energy MS-PS3-1 Construct and interpret graphical displays of data to describe the relationships of kinetic energy to the mass of an object and to the speed of an object. MS-PS3-5 Construct, use, and present arguments to support the claim that when the kinetic energy of an object changes, energy is transferred to or from the object. (page 1) Engineering Design MS-ETS1-1 Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions. MS-ETS1-2 Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem. MS-ETS1-3 Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved. MS-ETS1-4 Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved. Common Core State Standards Connections: ELA/Literacy RST.6-8.3 Follow precisely a multistep procedure when carrying out experiments, taking measurements, or performing technical tasks. WHST.6-8.1 Write arguments focused on discipline-specific content. Facilitate SCIENCE Inquiry Encourage inquiry using a strategy modeled on the research-based science writing heuristic. Student work will vary in complexity and depth depending on grade level, prior knowledge, and creativity. Use the prompts liberally to encourage thought and discussion. Student Copy Masters begin on page 14. Explore Understanding Ask students to think about how they walk a line, cross a balance beam, or stay upright on inline skates or a skateboard. What kinds of actions do they do to ensure they stay upright? Why are these actions necessary? Extending arms while balancing oneself helps.... Bending low helps maintain balance by.... When maintaining balance the body’s center of mass.... When involved in the complex physical movements required to play a sport, the body’s center of mass... The center of mass can be located experimentally by.... Show Physics of Figure Skating and encourage students to jot down notes on center of mass and projectile motion as they watch. Continue the discussion of center of mass or projectile motion with prompts such as: When I watched the video, I thought about.... Center of mass was emphasized in the video because.... A skater controls the relative location of his or her center of mass by .... The most important property of projectile motion, according to the video, is.... The shape of a projectile’s path can be explained as.... Objects that I’ve seen travel in a parabola include... Some difficulties one might encounter in locating an object’s center of mass are.... The center of mass might be calculated mathematically by.... Some difficulties in mathematically calculating the location of the center of mass might be.... (page 2) Ask Beginning Questions Stimulate small-group discussion with the prompt: This video makes me think about these questions.... Then, ask groups to list questions they have about the concepts of center of mass or projectile motion. Ask groups to choose one question and phrase it in such a way as to be researchable and/or testable. The following are some examples: Why must a skater’s center of mass remain over the point of contact with the ice? How does an object behave when its center of mass is not above the contact point? Is it possible for an object’s center of mass not to be on the object? What methods exist for experimentally determining an object’s center of mass? What are some ways you could arrive at a formula for mathematically calculating an object’s center of mass? How might we record a projectile’s actual path? What technology tools might help analyze a projectile’s path to see if it is a parabola? What are other places where we have seen parabolas? Design Investigations Choose one of the following options based on your students’ knowledge, creativity, and ability level and your available materials. Actual materials needed would vary greatly based on these factors as well. Possible Materials Allow time for students to examine and manipulate the materials that are available. Doing so often aids students in refining their questions or prompts new ones that should be recorded for future investigation. In this inquiry, if students choose to study center of mass, they might obtain a meter stick, an electronic or triple beam balance, and a set of standard masses. (See Connect to Engineering in The Physics of Figure Skating INTEGRATION GUIDE for additional ideas/resources)If students choose to study projectile motion, they might use a poster board, a marker, a meter stick, a small object to throw, and smartphones or other video recording device. Safety Considerations Augment your own safety procedures with NSTA’s Safety Portal at http://www.nsta.org/portals/safety.aspx. Open Choice Approach(Copy Master page 14) Groups might come together to agree on one question for which they will explore the answer, or each group might explore something different. One such idea is determining and/or predicting the location of an object’s center of mass. (The object might be geometrically simple to facilitate good predictions, or complex to make the problem more challenging.) Another idea might be analyzing projectile motion to see if the path is truly parabolic. (See Connect to Math in The Physics of Figure Skating INTEGRATION GUIDE.) Students taking physics might analyze the horizontal and vertical positions as functions of time. Give students free rein in determining how they will explore their chosen question. To help students envision possible investigations, use prompts such as the following: An example of an object simple enough to allow computation of center of mass would be.... We will predict the location of the center of mass by.... We will experimentally locate the center of mass by.... We can gather data on a projectile’s path by.... We can find the equation of such a parabola by.... The kinds of evidence we need in order to support our claim include.... Students should brainstorm to form a plan they would have to follow in order to answer their question, which might include researching background information. Work with students to develop safe procedures that control variables and enable them to make accurate measurements. Insist that they get your approval on their procedures before they start any investigation. Encourage students with prompts such as the following: Information we need to understand before we can start our investigation is.... The variables we will test are.... The variables we will control are.... The steps we will follow are.... We will record and organize our data using.... To conduct our investigation safely, we will.... To explore the concept of center of mass in a system, students might choose an object such as a meter stick and place standard masses on it at predetermined locations. They might then predict that the location of the center of mass of the system has changed because the masses have been added to it and then find the center of mass experimentally, to see whether their predictions were correct. To explore projectile motion, students might video a projectile in flight against a gridded background (which will show a parabolic curve), and then illustrate it mathematically by plotting points on their gridded background or analyzing their data (perhaps using a spreadsheet program such as Excel) to see if it conforms to a simple theoretical and mathematical model of projectile motion. A Projectile Motion Illustrator that allows variables to be easily manipulated can be found at: http://staff.hartdistrict.org/glyle/tools/projectile_motion/projectile_motion.htm) Students might extend their investigations by exploring how parabolas and their applications can be seen in the everyday world. (page 2) Focused Approach(Copy Master pages 15–16) The following exemplifies how students might predict and then measure the location of the center of mass of a fairly simple, essentially one- dimensional object, such as a meter stick with standard masses placed on it. Ask students questions such as the following to stimulate their thinking: What kinds of evidence can you collect that will be appropriate for supporting your claim(s)? Where should the center of mass of a long uniform object like a meter stick be, and why? How can we experimentally locate the center of mass of a long uniform object like a meter stick? How would the center of mass in a system change if an external mass were placed closer to one end of a long uniform object like a meter stick? Students might obtain a meter stick and a set of standard masses or coins (e.g., nickels, ~5 g each.) The meter stick is a good choice of object for this experiment because.... Even though we have standard masses, we will need to measure.... We can locate the center of mass experimentally by.... Students might now measure the mass of the meter stick (because its mass does contribute to the center of mass of the system). They might then choose two standard masses and place them on the meter stick, each centered carefully at some chosen centimeter mark. They might then use logic to estimate (without doing any explicit calculations) the position of the center of mass. We chose the masses and positions we did because.... The position of the meter stick’s own center of mass is.... We agree that the center of mass will be at.... Students might now calculate the position of the center of mass as a weighted average of the positions of the different masses. Encourage student to devise the method on their own but if they get stuck provide hints pointing them toward the following method. The center of mass can be found by multiplying each mass’s position (centimeter mark) by the mass (i.e., in grams), adding all these up, and then dividing this sum by the total mass. As an example (using an object with a uniform shape and equal distribution of mass) if the meter stick’s mass is 100 grams, and we centered a 200 gram mass on the 10 centimeter mark and a 500 gram mass on the 90 centimeter mark, the center of mass should be at [(100 × 50) + (200 × 10) + (500 × 90)]/(100 + 200 + 500) = 52,000/800 = 65 centimeters. We will calculate the location of the center of mass by.... This location differs from our non-calculated guess by.... Our calculation can be confirmed by... Center of mass can determined without calculation by... Students might now experimentally determine the center of mass by placing the meter stick on a small cylinder (perhaps another standard mass from the same set), or hang it from a string if the standard masses are also hanging from the meter stick, or balance the meter stick on a triangular prism) and gently roll/slide the meter stick along it until it balances. Care should be taken to do this as accurately as possible, by rolling it back and forth a few times either side of the balance point to zero in on it, and by carefully noting just where the cylinder touches the meter stick. Help students understand what they are doing, using these or similar prompts: Balancing the meter stick this way locates the center of mass because.... We can enhance the accuracy of our measurement by.... The difference between our calculated center of mass and the one we measured is.... Some possible sources of error in this experiment are.... Students might repeat this process with a few other combinations of masses and locations. Each time, they might try to refine not only their technique but also their initial guesses. An interesting possibility would be to record which group members made the best predictions, and use a weighted average (greater weight given to the students with better guessing ability) and see if this improves the group’s predictions. (page 3) Adapt for High School Students High school students may have had algebra, giving them the skills to manipulate the equation for finding center of mass to solve for specific variables. They might choose the location for one mass, but then specify where they want the center of mass to be, and then use algebra to solve for the required position of the other (known) mass. Using the masses given in the example above, they might decide they want the 200 gram mass at the 10 centimeter mark, and the center of mass itself to be at the 65 centimeter mark, so that the question now becomes where to place the 500 gram mass (the answer in this example being the 90 centimeter mark). Physics students might be able to sketch diagrams indicating forces and the center of mass for the system they are studying. Game Option for All Ages Students might form groups, each group deciding on a somewhat complex (not too symmetrical) shape to cut out of cardboard. The teacher might specify (or students might agree upon) some rules regarding the size or shape. For instance, the longest dimension could be fixed at 20 centimeters, and the shape should be such that the center of mass is actually on the figure (it is sometimes possible for it to be in the air between branches of a figure). Groups could then swap their cutouts with other groups or they might be distributed randomly. By visual inspection alone (no manipulating of the figure allowed) each group might estimate where on the figure the center of mass (younger students might use terms like balance point or middle) should be, and place a mark there. Then, looking only at the other side of the figure, they might find the true center of mass by either of two methods: (1) trying to balance the figure on a pencil point or (2) hanging the figure from a string attached to one point and tracing a line across the figure as an extension of the string, attaching the string at another point about a quarter of the way around the figure and repeating the process, and then taking the intersection of the lines as the center of mass. Students might then measure how far their guess was from the true position. The group with the smallest distance (from the actual center of mass) wins. Note: a good way to ensure objectivity is to place the measured center of mass mark on the side opposite the guessed one, but this makes them hard to compare. Students might push a pencil point through one mark to see how it matches on the other side, but teachers should take safety precautions if students are using sharp objects for this. To allow several groups to examine the same shape, students might place a marker, such as a coin, over their determined location of the center of mass and take a picture (using their smart phone) that shows the entire object with their marker in place. The picture can then be compared with the actual location of the center of mass. Make a Claim Backed by Evidence As students carry out their investigations, ensure they record their observations as evidence to support their claims. As needed, suggest ways they might organize their data using tables or graphs. Students should analyze their data and then make one or more claims based on the evidence their data shows. Encourage students with this prompt: As evidenced by... I claim... because.... An example claim regarding the center of mass of a system consisting of a meter stick with other masses placed on it might be: As evidenced by the fact that placing a larger mass on the meter stick moved the center of mass towards that mass, I claim that the position of the mass should be multiplied by that mass, because incorporating this multiplication in the calculation gave good agreement between our calculated and measured positions for center of mass. (page 4) Present and Compare Findings Encourage students to prepare presentations that outline their inquiry investigations so they can compare results with others. Students might do a Gallery Walk through the presentations and write peer reviews, as would be done on published science and engineering findings. Students might also make comparisons with material they find on the Internet, the information presented in the video, or an expert they chose to interview. Remind students to credit their original sources in their comparisons. Elicit comparisons from students with prompts such as the following: My ideas are similar to (or different from) those of the experts in the video in that.... My ideas are similar to (or different from) those of my classmates in that.... My ideas are similar to (or different from) those that I found on the Internet in that.... Students might make comparisons like the following: My ideas are similar to those found by other groups in my class—my classmates also reported good agreement between calculated and measured positions of center of mass. Reflect on Learning Students should reflect on their understanding, thinking about how their ideas have changed or what they know now that they didn’t before. Encourage reflection, using prompts such as the following: I claim my ideas have changed from the beginning of this lesson because of this evidence... My ideas changed in the following ways... I wish I had been able to spend more time on.... Another investigation I would like to try is.... I have learned (or better understand) that.... Inquiry Assessment See the rubric included in the student Copy Masters on page 20. (page 5) Facilitate ENGINEERING DESIGN Inquiry Encourage inquiry using a strategy modeled on the research-based science writing heuristic. Student work will vary in complexity and depth depending on grade level, prior knowledge, and creativity. Use the prompts liberally to encourage thought and discussion. Student Copy Masters begin on page 17. Explore Understanding Guide a discussion to find out what students know about systems. Use the following or similar prompts to start students talking. A system is.... An example of a system is.... The parts of a system are related because.... The two people in pairs skating make up a system because.... Show The Physics of Figure Skating and encourage students to take notes on what they observe about pairs figure skaters while they watch. Continue the discussion about systems using the following or similar prompts: When I watched the video, I thought about.... The experts in the video explained that.... To stay on their feet, figure skaters have to.... To keep from falling during a lift, pairs skaters have to.... The system of pairs skaters is made up of.... Identify Problems Stimulate small-group discussion with the prompt: This video makes me think about these problems.... Then have small groups list questions they have about the pairs skating system, the center of mass, or projectile motion. Ask groups to choose one problem and phrase it in such a way as to reflect an engineering design problem that is researchable and/or testable. Remind students that engineering design problems usually have multiple solutions. Some examples are: What is the best way to model a system made of similar parts like two skaters? What is the best way to model a system made of dissimilar parts like a skater skating with a hoop, or a flag? What is the best way for a person to remain balanced while changing positions? What is the best angle to launch a projectile so that it travels the farthest? Design Investigations Choose one of the following options based on your students’ knowledge, creativity, and ability level and your available materials. Actual materials needed would vary greatly based on these factors as well. Possible Materials Allow time for students to examine and manipulate the materials you have available. Doing so often aids students in refining their questions or prompts new ones that should be recorded for future investigations. In this inquiry, students might use toy cars or trucks, balls, transparent balloons, coins, modeling clay, card stock (or index cards of various sizes), paper clips, cardboard, scissors, a compass for drawing circles, large washers, a large funnel, large balls, small single piece tops, wooden rulers, jacks, or wind-up toys. If students are (page 6) interested in modeling the center of mass of a person, they might use a jointed doll. If students are interested in investigating projectile motion, they might build a catapult using a ruler or a plastic spoon, wood blocks, tape, glue, or other materials. Be sure that students launch items that are small and light, such as marshmallows or uniform sized packing peanuts. Students may also need tools or measuring devices such as protractors and meter sticks. Make sure students understand and know how to use the various tools safely prior to the activity. Safety Considerations Augment your own safety procedures with NSTA’s Safety Portal at http://www.nsta.org/portals/safety.aspx. Open Choice Approach(Copy Master page 17) Groups might come together to agree on one problem for which they will design a solution, or each group might explore different problems, such as finding the best way to model a system of pairs skaters, finding the best way for a model of pairs skaters to remain balanced while changing positions, or finding the impact on a system’s balance when pairs skaters skate closer or further away from each other. Give students free rein in determining how they will engineer their solutions, but insist that they get approval before building and testing. To help students envision their investigations, such as one pertaining to finding the best angle to launch a projectile, use prompts such as the following: The problem we are solving is.... The materials we could use are.... We are designing a solution that will.... Acceptable evidence for our solution would include.... Lead whole-class or small-group discussion to establish the criteria and constraints within which solution will be designed. Remind students that criteria are factors by which they can judge the success of their effort and that constraints are limitations to the effort and are often related to materials, time, or money. We think we can solve the problem by.... Our criteria for success are...and we will determine them by.... Constraints that might limit the range of potential solutions are.... Students should brainstorm to form a plan they would have to follow in order to solve the problem, which might include researching background information. Work with students to develop safe procedures that enable them to collect data. For example, to find the best angle to launch a projectile, students might build a small catapult that has an adjustable arm. Students can then launch a small, light object with the catapult, changing the angle of the arm between launches, and measuring the distance that the object travels during each launch. Encourage students with prompts such as the following: Information we need to understand before we can start our investigation is.... Our drawing of our prototype will show.... We will construct our prototype or model by.... We will test our prototype or model by.... We will record and organize our data using.... To conduct our investigation safely, we will.... After communicating information to the class about their solution and reflecting on their own solution as well as those of other groups, allow the class or small groups to go through a redesign process to improve their solutions. (page 7) Focused Approach(Copy Master pages 18–19) The following suggests ways students might establish a set of criteria and constraints for a system and then find a solution to the problem, What is the best way to model a system made of parts that interact in different ways? Give students leeway in determining exactly how the parts of their system will interact, but insist that they get your approval on their procedures before they start any investigation. Allow time for groups to examine all of the materials available to them. Guide whole-class or small-group discussion to identify the problem they are solving and then to identify criteria and constraints within which their solution will be developed. Remind students that criteria are factors by which they can judge the success of their effort and that constraints are limitations to the effort and are often related to materials and time. Use prompts such as the following: The problem we are solving is.... The materials we could use are.... We are designing a solution that will.... As shown in the video our system explores... The science concepts that we will need to use in creating our design include.... We think we can solve the problem by.... Our criteria for success are.... Constraints that might limit the range of potential solutions are.... Acceptable evidence that would support our claims of success for our design include.... Encourage students to think about what parts make up their system. Also tell them to consider how the parts of their system act when they are alone and the way the parts of the system act when they are joined together. Use prompts such as the following in your discussion. The parts of our system are.... When the parts of the system act alone they.... When the parts of the system act together they.... We can model a system using _____ because.... We are not going to use _____ because we think it/they will.... Students might need help finding ways to measure the motion of their system. Explain that methods include measuring the distance the objects move, calculating the average speed of the objects, or observing the direction the objects move or how fast the objects spin. If needed, review how to calculate the average speed of an object. Students could use coins or cardboard and sticky modeling clay to build a system. Encourage students to plan and identify the parts of their system, and then predict and explain how those parts will interact. For example, students might build a system using cardboard circles and two (unequal mass) clumps of sticky modeling clay (or other sticky substance). Each of the pieces of clay represents a skater and when placed on the cardboard circle become part of the system. The initial motion of the skater might result from being released from the top of an inclined plane. Students might use the system to discover how the skaters’ relationship to each other on the cardboard circle affects the balance of the system and speed at which it might travel a certain distance. Some students might try a similar approach to the cardboard circles, but instead use single-piece toy tops or jacks. Clay clumps attached to different parts could again model the skaters. Help students visualize this procedure using these or similar prompts: The interacting parts of our system will be.... The ways that the parts of the system will interact are.... We will measure the motion of our system by.... We will measure the motion of our system _____ times because.... Our system could be used to model pairs skaters because.... Students might also choose to model a system with two skaters by spinning two coins inside a clear balloon. After placing the two coins inside the balloon through the neck, students would inflate the balloon, tie it off, and then control variables such as balloon size and the way they set the coins in motion to observe how the two coins act. Help students visualize this procedure using these or similar prompts: The interacting parts of our system will be.... The ways that the parts of the system will interact are.... We will measure the motion of our system by.... Using the same size coins impacts motion by.... Using different sized coins impacts motion by.... Changing the motion of the balloon.... The coins move together when.... The coins do not move together when.... After communicating information to the class about their solution and reflecting on their own solution as well as those of other groups, allow the class or small groups to go through a redesign process to improve their solutions. (page 8) Make a Claim Backed by Evidence As students carry out their investigations, ensure they record their observations and measurements. Students should analyze their observations in order to state one or more claims. Encourage students with this prompt: As evidenced by... I claim... because.... or I claim our design (was/was not) successful because.... An example claim might be: As evidenced by the recorded speed of our cardboard/clay system, I claim that a pair of figure skaters will travel over the measured distance faster when they are balanced (as near as possible) on either side of the cardboard wheel because the wheel systems that were unbalanced traveled slower or were unable to go the measured distance. Present and Compare Findings Encourage students to prepare presentations that outline their inquiry investigations so they can compare results with others. Students might do a Gallery Walk through of the presentations and write peer reviews, as would be done on published science and engineering findings. Students might also make comparisons with material they find on the Internet, the information presented in the video, or an expert they chose to interview. Remind students to credit their original sources in their comparisons. Elicit comparisons from students with prompts such as: My findings are similar to (or different from) those of the experts in the video in that.... My findings are similar to (or different from) those of my classmates in that.... My findings are similar to (or different from) those that I found on the Internet in that.... Students might make comparisons like the following: My results were similar to those of my classmates in that balanced systems traveled faster than unbalanced systems. Reflect and Redesign Students should reflect on their understanding, thinking about how their ideas have changed or what they know now that they didn’t before. They should also evaluate their own designs in light of others’ presentations and propose changes that will optimize their designs. Encourage reflection, using prompts such as the following: My ideas have changed from the beginning of this lesson because evidence showed that.... My design would be more effective if I _____ because I learned that.... My ideas changed in the following ways.... When thinking about the claims made by the experts, I am confused about.... One part of the investigation I am most proud of is.... Inquiry Assessment See the rubric included in the student Copy Masters on page 20. (page 9) COPY MASTER: Open Choice SCIENCE Inquiry Guide for Students Physics of Figure Skating Use this guide to investigate a question about center of mass or projectile motion. Write your report in your science notebook. Ask Beginning Questions Our class discussion and the video make me think about these questions.... Design Investigations Choose one question. Brainstorm with your teammates to come up with ways in which you might be able to answer the question. Look up information as needed. Add safety precautions. Use the prompts below to help focus your thinking. Information we need to understand before we can start our investigation is.... The variables we will test are.... The variables we will control are.... The steps we will follow are.... We will record and organize our data using.... To conduct our investigation safely, we will.... Record Data and Observations Record your observations. Organize your data in tables or graphs as appropriate. Make a Claim Backed by Evidence Analyze your data and then make one or more claims based on the evidence your data shows. Make sure that the claim goes beyond summarizing the relationship between the variables. My Evidence My Claim My Reason Present and Compare Findings Listen to presentations of other groups and create a peer review as scientists do for one another. You might also compare your findings with those of experts in the video or that you have access to, or material on the Internet. How do your findings compare? Be sure to give credit to others when you use their findings in your comparisons. My ideas are similar to (or different from) those of the experts in the video in that.... My ideas are similar to (or different from) those of my classmates in that.... My ideas are similar to (or different from) those that I found on the Internet in that.... Reflect on Learning Think about your results. How do they fit with what you already knew? How do they change what you thought you knew about the topic? My ideas have changed from the beginning of this lesson because of this evidence.... My ideas changed in the following ways.... One idea/concept I am still working to understand involves.... (page 10) COPY MASTER: Focused SCIENCE Inquiry Guide for Students Physics of Figure Skating Use this guide to investigate a question about how to predict and find the location of the center of mass of a system. Write your report in your science notebook. Ask Beginning Questions How can we calculate the location of an object’s center of mass? How can we experimentally locate an object’s center of mass? Design Investigations Brainstorm with your teammates to come up with ways in which you might be able to answer the question. Decide on one idea and write a procedure that will allow you to safely explore the question. Use the prompts below to help focus your thinking. Where should the center of mass of a long uniform object like a meter stick be, and why? How can we experimentally locate the center of mass of a long uniform object like a meter stick? How would the center of mass change if an object were placed off-center on a long uniform object like a meter stick? The meter stick is a good choice of object for this experiment because.... Even though we have standard masses, we will need to measure.... We can locate the center of mass experimentally by.... We chose the masses and positions we did because.... We agree that the center of mass will be at.... To conduct our investigation safely, we need to.... Record Data and Observations Organize your observations and data in tables or graphs as appropriate. The table below is an example of how students might record their data. Center of Mass of Meter Stick Loaded with Other Masses Trial Mass of Meter Stick (grams) Mass #1 (grams) Position (cm) of Mass # 1 Mass #2 (grams) Position (cm) of Mass # 2 Initial Guess for Center of Mass Location (cm) Calculated Center of Mass Location (cm) Measured Center of Mass Location (cm) 1 2 3 4 5 (page 11) Ideas for Analyzing Data How do you account for the average difference between your calculated values and your measured ones? What explains the accuracies/inaccuracies of your initial guesses? Which is more accurate, your calculations or your measurements? Why? How would you generate a model for how the center of mass changes for a system when two masses are introduced and separated by a distance? Make a Claim Backed by Evidence Analyze your data and then make one or more claims based on the evidence your data shows. Make sure that the claim goes beyond summarizing the relationship between the variables. My Evidence My Claim My Reason Present and Compare Findings Listen to presentations of other groups and create a peer review as scientists do for one another. You might also compare your findings with those of experts in the video or that you have access to, or material on the Internet. How do your findings compare? Be sure to give credit to others when you use their findings in your comparisons. My ideas are similar to (or different from) those of the experts in the video in that.... My ideas are similar to (or different from) those of my classmates in that.... My ideas are similar to (or different from) those that I found on the Internet in that.... Reflect on Learning Think about what you found out. How does it fit with what you already knew? How does it change what you thought you knew? I claim that my ideas have changed from the beginning of this lesson because of this evidence.... My ideas changed in the following ways.... One concept I still do not understand involves.... One part of the investigation I am most proud of is.... (page 12) Physics of Figure Skating Use this as a guide to make a model that you will use to solve an engineering design problem. Record all of your notes and observations in your science notebook. Identify Problems Our class discussion and the video make me think about problems such as.... Design Investigations Choose your materials and brainstorm with your teammates to discuss how you will answer your question. Take notes on your discussions. Use these prompts to help you: The problem we are attempting to solve is.... We are designing a solution that will.... Acceptable evidence for our solution would include... We think we can solve the problem by.... Our criteria for success are...and we will determine them by.... Constraints that might limit the range of potential solutions are.... To conduct our investigation safely, we will.... Test Your Model Record and organize your data and observations from your tests using tables and/or graphs. Make a Claim Backed by Evidence Analyze your results and make one or more claims based on the evidence your data shows. Make sure that the claim goes beyond summarizing the relationship between the variables. My Evidence My Claim My Reason Present and Compare Findings Listen to presentations of other groups and create a peer review as scientists do for one another. You might also compare your findings with those of experts in the video or that you have access to, or material on the Internet. How do your findings compare? Be sure to give credit to others when you use their findings in your comparisons. My findings are similar to (or different from) the experts in the video in that.... My findings are similar to (or different from) my classmates in that.... My findings are similar to (or different from) what I found on the Internet in that.... Reflect and Redesign Think about what you learned. How does it change your thinking? Your design? I claim that my ideas have changed from the beginning of this lesson in that.... My design would be more effective if I _____ because I learned that.... When thinking about the claims made by the experts, I am confused about.... One part of the investigation I am most proud of is.... (page 13) COPY MASTER: Focused ENGINEERING DESIGN Inquiry Guide for Students Physics of Figure Skating Use this as a guide to make a model that you will use to solve an engineering problem involving parts of a system. Record your notes and observations in your science notebook. Identify Problems What is the best way to model a system made of parts that interact in different ways? Design Investigations Discuss with your group how you might model different parts of a system. Then discuss how you will build a system that interacts in different ways. Use these prompts to help you. The parts of our system are.... When the parts of the system act alone they.... When the parts of the system act together they.... We can model a system using _____ because.... We are not going to use _____ because we think it/they will.... To be safe, we need to.... Test Your Model Make a drawing to depict the placement of each skater for each of your trials. Let X stand for the more massive skater and Y denote the other skater. Record and organize your observations and data in tables such as the one below. Object Distance from center line Distance traveled (cm) Time (s) Average speed (cm/s) Position 1 Positon 2 Position 3 Ideas for Analyzing Data How did the motion of the parts of your system change when the parts were working together? How is your system similar to a system of pairs skaters? How is your system different from a system of pairs skaters? (page 14) Make a Claim Backed by Evidence Analyze your results and then make one or more claims based on the evidence you observed. My Evidence My Claim My Reason Present and Compare Findings Listen to presentations of other groups and create a peer review as scientists do for one another. You might also compare your findings with those of experts in the video or that you have access to, or material from the Internet. How do your findings compare? Be sure to give credit to others when you use their findings in your comparisons. My findings are similar to (or different from) those of the experts in the video in that.... My findings are similar to (or different from) those of my classmates in that.... My findings are similar to (or different from) information I found on the Internet in that.... Reflect and Redesign Think about what you learned. How does it change your thinking? Your design? I claim that my ideas have changed from the beginning of this lesson in that.... My design would be more effective if I _____ because I learned that.... When thinking about the claims made by the expert, I am confused about.... One part of the investigation I am most proud of is.... (page 15) COPY MASTER: Assessment Rubric for Inquiry Investigations Criteria 1 point 2 points 3 points Initial question or problem Question or problem had had a yes/no answer or too simple of a solution, was off topic, or otherwise was not researchable or testable. Question or problem was researchable or testable but too broad or not answerable by the chosen investigation. Question or problem was clearly stated, was researchable or testable, and showed direct relationship to investigation. Investigation design The design of the investigation did not support a response to the initial question or provide a solution to the problem. While the design supported the initial question or problem, the procedure used to collect data (e.g., number of trials, or control of variables) was not sufficient. Variables were clearly identified and controlled as needed with steps and trials that resulted in data that could be used to answer the question or solve the problem. Variables (if applicable) Either the dependent or independent variable was not identified. While the dependent and independent variables were identified, no controls were present. Variables identified and controlled in a way that resulting data can be analyzed and compared. Safety procedures Basic laboratory safety procedures were followed, but practices specific to the activity were not identified. Some, but not all, of the safety equipment was used and only some safe practices needed for this investigation were followed. Appropriate safety equipment used and safe practices adhered to. Observations and data Observations were not made or recorded, and data are unreasonable in nature, not recorded, or do not reflect what actually took place during the investigation. Observations were made, but were not very detailed, or data appear invalid or were not recorded appropriately. Detailed observations were made and properly recorded and data are plausible and recorded appropriately. Claim No claim was made or the claim had no relationship to the evidence used to support it. Claim was marginally related to evidence from investigation. Claim was backed by investigative or research evidence. Findings comparison Comparison of findings was limited to a description of the initial question or problem. Comparison of findings was not supported by the data collected. Comparison of findings included both methodology and data collected by at least one other entity. Reflection Student reflection was limited to a description of the procedure used. Student reflections were not related to the initial question or problem. Student reflections described at least one impact on thinking. Lesson plans produced by the National Science Teachers Association. 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