Pendulum Inquiry - Wrecking Balls lesson plan

Pendulum Inquiry - Wrecking Balls

LESSON CONTENT

• Lesson Plan Template: 

  Learning Cycle (5E Model)

• Learning Objectives: What will students know and be able to do as a result of this lesson?

  
  
  The students will:
  • understand that changes can occur when variables are manipulated or changed within an investigation.
  • recognize and explain the need for repeated experimental trials.
  • identify familiar forces that cause objects to move, such as pushes or pulls, including gravity acting on falling objects.
  • use problem-solving skills (brainstorming, testing, lateral thinking, trial, and error) to design a pendulum/wrecking ball that will complete each task outlined in the class challenge.
  • record results and procedures to document their progress throughout the lesson.

• Prior Knowledge: What prior knowledge should students have for this lesson?

  
  
  Students should:
  • have knowledge of forces (gravity, friction, pushes and pulls).
  • recognize that energy has the ability to cause motion or create change.
  • be able identify familiar forces that affect how objects move.
  • be able to identify scenarios whereby gravity is overcome.
  • know about balanced and unbalanced forces.
  • know about gravity and friction and how they affect motion.

• Guiding Questions: What are the guiding questions for this lesson?

  
  
  1. What causes objects to move or be set in motion?
  2. If traveling in a car with no seat belt, what would happen to you if someone suddenly slammed on the brakes? Why would this occur?
  3. When two objects collide what happens?
  4. Can a pendulum move an object at rest? How? Have you ever seen that happen? Explain.

• Engage: What object, event, or questions will the teacher use to trigger the students' curiosity and engage them in the concepts?

  
  
  1. Engage the students with the video LG&E Building vs. Wrecking Ball.
  2. Ask students, "Could a wrecking ball like the one we just saw in the video be considered a pendulum? Explain your thinking."
     Possible response: Yes, because it is swinging from a fixed point.
  3. Explain that a wrecking ball is indeed a pendulum.
  4. Discovery questions:
     • "How might Newton's Second Law of Motion apply to a wrecking ball? Law #2: If a force acts on an object, the object moves in the direction of that force." 
       Possible response: When a wrecking ball slams into the concrete or bricks of a building it will move the concrete or bricks in the direction of the wrecking ball until the force of gravity pulls the material to the ground.
     • "How might Newton's Third Law of Motion apply to a wrecking ball? Law #3: For every action, there is an equal and opposite reaction."
       Possible response: When a wrecking ball hits a building it will cause materials in the building to smash, move and fall to the ground due to gravity.
     • "So when a wrecking ball hits an object, according to Newton's Laws of Motion, what should be the result?"
       Possible response: Destruction!
  5. Introduce the vocabulary for the lesson. Use the attached Wrecking_Ball_Vocab.docx sheet to access all learners.
     • Balanced forces: two forces acting in opposite directions on an object, and equal in size.
     • Unbalanced forces: two forces acting on an object are not equal in size. Can cause motion of an object, for example a wrecking ball.
     • Gravity: the force that tries to pull two objects toward one another.
     • Friction: a force that holds back the movement of a sliding object. Only occurs with solid objects.
     • Air resistance: the friction exerted on an object moving through the air.
  6. Project the attached vocabulary support document on the class document camera. A term, definition and picture example is provided for each vocabulary word. Students can copy this into their science journals if they are used or a separate sheet of paper. Encourage students to come up with their own picture examples. To challenge students the teacher can keep the picture example column covered until students discuss their own examples.
  7. Explain to students that they will use their understanding of pendulums and these vocabulary words to help them design their own wrecking balls in the next phase of the lesson.

• Explore: What will the students do to explore the concepts and skills being developed through the lesson?

  
  
  Each engineering team will require a set of the following materials: 3 large washers, length of string that can be measured to 15 cm, yard stick, unsharpened pencil, protractor, sticker or other marker to serve as the fixed starting point for each test, attached recording sheet-one per student.
  1. Assign students to engineer teams of 2-3 for the "Testing" phase of the lesson. Pass out materials to each group. Tell students they may not touch the materials until all directions are given and understood.
     • Note: The pendulums from the previous lesson would work well for this lesson as and save on time and materials. They match the design described below.
  2. Explain to students that they will be designing a pendulum/wrecking ball to test for performing the task of moving and/or knocking down a "building" the greatest distance. Students will be allowed to manipulate set variables to achieve a pendulum design they feel will move their building the greatest distance.
  3. Next, introduce the challenge so students understand the end goal of the lesson. However, this phase will be focused on the students testing with the wrecking balls and materials in order to determine the preferred specifications to accomplish the challenge goal.
     • Challenge Activity: The Wreck-It Right construction company is looking to hire a team of engineers to design new and effective wrecking balls for their company. Wreck-It Right needs to ensure they are hiring the right engineering team for the job. They have posed a challenge for all the engineers in your community to compete in. The engineering teams' mission will be to design a pendulum/wrecking ball that will move a "building" over the greatest distance from a fixed starting point. The engineering teams will have time to conduct trials in order to determine the specification for the most effective final product for on-site testing. The top three designs will be hired by the company to handle all of their destruction and demolition needs. Use your knowledge of pendulums, mass and gravity to design your pendulum/wrecking ball. Good luck, engineering teams, and good designing.
  4. Review the goals for the challenge:
     1. Determine the specifications for the wrecking ball that will move/knock the building the greatest distance from the fixed measuring point.
     2. Students are restricted to changing only the variables on the attached Student_Recording_Sheet.docx.
  5. Changes to variables for this lesson should be limited to the following:
     • degrees (angle) from the center point of the pendulum
     • string length
     • mass of the bob
  Pendulum Design:
  Tie one end of a string measuring 15 cm to a large washer and the other end to an unsharpened pencil. The pencil will be the fixed point, and also used to lengthen or shorten the string by twisting the pencil to wrap the string around it. Demonstrate to the engineering teams how to design this type of pendulum, pointing out the parts (bob/mass, string, fixed point).
  The teacher should actually build his/her own as an example for construction as well as other examples throughout the lesson.
  
  Pencil image from OpenClipArt.com; diagram designed in Paint
  1. Let all engineering teams construct the same pendulum with the materials provided for testing and reference. All students should design a pendulum with one large washer on one end and a string length of 15 cm.
  2. Explain to students that they are going to use their pendulums as wrecking balls to perform a specific challenge task.
  3. Demonstrate how to measure the degree of angle from the center with a protractor with the teacher pendulum:
     • Turn the protractor so that the straight side is in line or parallel with the pencil (the pencil and protractor should both be horizontal).
     • As the students pull back on the pendulum bob, they can measure the degrees from the center by reading where the string crosses the protractor and record it.
     • For an example of this, see Figure H in the Simple Pendulum experiment from Loren Winters' AP Physics B Online.
  4. Tell students that they will work in engineering teams to design a pendulum/wrecking ball that will be able to move a "building" the greatest distance (cm). Students should consider degrees from the center, string length, and mass of the bob as they create their designs, but it is important they understand they will be changing these variables independently of one another. Engineering teams should only be changing one variable at a time as they test their wrecking balls.
  5. Have groups decide upon and assign roles:
     1. pendulum holder (the student who will hold the pendulum for the tests)
     2. variable controller (the student who will control, monitor, and change the variables for the tests)
     3. building measurement taker and recorder (the student who will use the yard stick to measure the distance the building moved after being knocked by the pendulum and record the results for their team members to record later)
  6. During the testing phase, students will be testing their wrecking balls, which have been constructed with the given materials, and changing variables to determine the best design for moving/knocking down the "building" the greatest distance from a fixed starting point.
  7. Students will repeat their trials four times, using a yardstick to measure the distance (in cm) traveled by the building and recording the results for each trial on the attached Student Recording Sheet.
     • Students will find the average distance traveled (rounded to nearest whole cm) and record their results and conclusions for discussion on their recording sheets.
     • The measurement taker should be measuring a straight line from the fixed starting point to the final resting place of the building for each test swing. The teacher may need to demonstrate this to ensure that students are measuring accurately.
  8. The attached student recording sheet designates the variables to be changed for each round of tests for the students. The attachment is a Word document and can be adjusted, so if you feel that your particular students would benefit from the freedom to select which variables to change, you can easily adjust the recording sheet for students to do so.
     • Note: The teacher should be cautioned that students can easily begin changing too many variables at once, and the validity of their investigation will break down quickly. For this reason, the variables to be changed during the testing have been chosen for the students. Students will use the results of experiments with these pre-determined variables to decide what wrecking ball design will produce the best pendulum for moving the test-site building and adjust their pendulums accordingly.
  Prior to tests:
  The engineering teams should decide where they will conduct their tests, on the floor or a desk. They will place the sticker or other marker in a place where there will be plenty of room for the wrecking ball and building to move. This will be the fixed measuring point where they will place the building for each test. Additionally, teams should position the pencil directly over this fixed measuring point for each test to avoid accidentally introducing another variable and ensure that their tests are consistent. Students should take their building movement measurements in a straight line from the fixed measuring point to the final resting place of their building. Directions for creating the building are provided below. Each student can make his/her own building to keep students engaged. Student teams should choose one team member's building to conduct their tests.
  For the angle tests:
  1. Engineering teams will test the best release angle for their wrecking ball. The only variable they will change for this test will either be adjusting the angle to 40 or 60 degrees as the teacher has already demonstrated.
  2. The length of the pendulum at this point should be the original length of the string 15 cm, minus the amount used to tie to the washer and pencil.
  3. There should also only be one washer tied to the string at this point.
  4. Students will conduct their tests for both angles, measuring the distance the building is knocked/moved each time.
  5. From the averaged results, the teams will determine the most effective release angle for their wrecking ball. This will be the release angle they will use for the remaining two variable tests. For example, if a team determined that 60 degrees was the more effective release angle, they would use this angle when they test bob mass and string length.
  For the string length tests:
  1. Students will test each string length by twisting the fixed point (pencil) to lengthen or shorten the string.
  2. Students should use the yard stick to ensure that the string length measures 12 or 8 cm.
  3. A small piece of tape can be given so the students can secure the string on the pencil to maintain the correct length. Make sure the tape does not impede the swinging of the wrecking ball.
  4. Students will conduct their tests, and then analyze their results to determine which string length moved the building the greatest distance. This will be the string length they will keep and use to test the mass of the bob. For example, if a team determined that 60 degrees and 12 cm produced the best results, these would be the specifications they would use to test the bob mass.
  For the bob tests:
  1. Students will conduct tests to determine the best bob mass for their wrecking ball.
  2. They will start with the original washer, and tie a second washer to the first. They should tie the washers side-by-side; attaching the washers underneath one another would actually change the length of the pendulum, which would affect the validity of their tests.
  3. The students will conduct their tests with two washers, and then do the same with three.
  4. The teams will use their results to determine the most effective bob mass.
  Full-class trials
  1. Now teams will use all of their results to design wrecking balls with the specifications that produced the most effective results during their tests. For example, if test results for a team determined that a release angle of 60 degrees, a string length of 12 cm, and a bob mass of two washers produced the best results, this will be the pendulum specifications this team of students will use to conduct their trials at the class testing site.
     • Note: Although this will be group work, each student should complete their own recording sheet. The team recorder can write down results as the teams test with their wrecking balls and the rest of the group may copy it from the recorders sheet after all tests are conducted.
  2. As the students are testing, the teacher should be circulating among teams to monitor and assist as needed. After teams have completed a few tests, the teacher may pose the following questions to the class:
     • "How has changing one variable affected the distance the building traveled?"
     • "Did the building travel a farther or shorter distance or was there no change? Explain these results."
  3. Once all testing is complete, students should make sure they have filled in their individual student recording sheets. They may copy from their team recorder. Make sure students also complete the concluding statement on their recording sheet and circle the specifications they will be using for their wrecking balls at the class test site. Encourage students to use the new vocabulary for the lesson in their conclusions and explanations.
  Teacher note: Although students are changing the same sets of variables in this lesson, each group will have their own ideas for the "best" or most effective combination of these variables to perform the task. As students test their wrecking balls and record class totals, good discussion may take place to explain why or why not some designs worked better than others. Additionally, if students choose the same designs with the same variables, discussion can take place as to why that particular combination of variables worked so effectively. This will allow students to reflect on their decision making process and further analyze their results.
  Directions for creating "buildings" for the wrecking balls to knock down:
  1. A week or so before conducting this lesson, the teacher should instruct students to save their empty school milk cartons after lunch.
  2. To keep students invested in the lesson and engaged, each student may make his/her own "building."
  3. Ensure the milk cartons are thoroughly washed of all milk residue and dry them out for at least a day prior to decorating them.
  4. After the milk cartons are washed and dried, the teacher should staple them closed at the top using one staple.
  5. To incorporate an art element into the lesson, the students can use tempera paint to paint their milk cartons to resemble a building of their design. Encourage students to be as creative as they wish.
  6. Allow the buildings to dry before using them in the challenge activity.
  7. As students are testing, buildings may need to be swapped out with those designed by other team members in the event that the first building becomes damaged. Swap buildings as needed, as the only significant difference between buildings will be the designs.

LG&E Building vs. Wrecking Ball... - SafeShare.tvtv

https://safeshare.tv/x/olaxrCNyuq

• Explain: What will the students and teacher do so students have opportunities to clarify their ideas, reach a conclusion or generalization, and communicate what they know to others?

  
  
  1. The teacher will construct the class testing site. This should be a place where the class can easily gather around to view each others results. Each engineering team will take turns testing their wrecking ball at this site while the rest of the engineering teams observe.
  2. To construct the class test site for the challenge activity, the teacher should place a sticker or marker on a desk or the ground to designate the fixed measuring point. The teacher can use one of the student buildings or make one specifically for class tests. Swap out the buildings as needed.
  3. Review the challenge: The Wreck-It Right construction company is looking to hire a team of engineers to design new and effective wrecking balls for their company. Wreck-It Right needs to ensure they are hiring the right engineering team for the job. They have posed a challenge for all the engineers in your community to compete in. The engineering teams' mission will be to design a pendulum/wrecking ball that will move a "building" over the greatest distance from a fixed starting point. The engineering teams will have time to conduct trials in order to determine the specification for the most effective final product for on-site testing. The top three designs will be hired by the company to handle all of their destruction and demolition needs. Use your knowledge of pendulums, mass and gravity to design your pendulum/wrecking ball. Good luck, engineering teams, and good designing.
  4. Review the goals for the challenge:
     • Determine the specifications for the wrecking ball that will move/knock the building the greatest distance from the fixed measuring point.
     • Students are restricted to changing only the variables on the attached student recording sheet.
  5. Each engineering team will demonstrate their pendulum/wrecking ball design to the class and complete swings swings at the target. Each engineering team will record their results at the test site on the last table of the attached student recording sheet. The average distance (in cm) will be their final score.
  6. As the teams complete their testing and determine their official number, the teacher will record it on the board so that all students may keep track of which three teams are in the running to be hired by Wreck-It Right Construction!
  7. After all teams have completed their swings and results have been recorded, determine the three teams that were able to design the wrecking ball that could move the test building the greatest distance. This will be the three teams with the highest averages.

• Elaborate: What will the students do to apply their conceptual understanding and skills to solve a problem, make a decision, perform a task, or make sense of new knowledge?

  
  
  1. To close the lesson, the teacher should bring the students back to whole group. The teacher should now facilitate a class discussion about why the students believe the three engineering teams had the most effective design. Encourage students to reflect on their own results and that of their classmates. Students should have their recording sheets to reference. Discuss differences in specifications and how they may have helped or hindered results. Perhaps one group used too much weight, or used too long of a string.
  2. Also discuss what other variables could be changed that were not in this particular lesson and how they might affect the distance the object traveled, such as building size, shape or weight. Encourage students to use the new vocabulary for the lesson in their conclusions and explanations.
  Conduct the Summative Assessment:
  The teacher can have the students answer the following journal prompts in their science journals if they are used, or a separate sheet of paper if they are not. Student responses to these journal prompts will either demonstrate a mastery of the aligned standards and the student's ability to articulate what they've learned in the lesson, or indicate that further practice needs to take place with these skills. Encourage students to use vocabulary in their responses.
  Journal Questions:
  1. How did changing each variable affect the distance the object traveled? Why do you think this occurred?
  2. After watching all of the pendulum/wrecking ball demonstrations, what would you have changed about your design?

• Summative Assessment

  
  
  The teacher can have the students answer the following journal prompts in their science journals if they are used, or a separate sheet of paper if they are not. Student responses to these journal prompts will either demonstrate a mastery of the aligned standards and the students' ability to articulate what they've learned in the lesson, or an indication that further practice needs to take place with these skills.
  Journal Questions:
  1. How did changing each variable affect the distance the object traveled? Why do you think this occurred?
  2. After watching all of the pendulum/wrecking ball demonstrations what things would you have changed about your design?

• Formative Assessment

  
  
  This lesson outlines pendulum investigations for students to explore in a hands-on manner to investigate the effects of gravity, mass and energy transfer. As these are investigations for the students to explore the workings of pendulums they may not require a large working knowledge of them before conducting this lesson. By asking the guiding questions for the lesson, however, the teacher can determine what current prior knowledge the students possess for gravity and forces that act on falling objects. If students have a limited understanding of concepts related to these questions, some simple demonstrations of dropping objects and observing/discussing the results will build this understanding. Additionally, the Pendulum Inquiry lesson prior to this one was designed for the specific purpose of building students' background knowledge.
  1. How does the force of gravity affect a falling object?
  2. Can we drop an object and have it not hit the floor? How?
  3. When an object is tied to a string and dropped what will occur? What forces are acting on the dropped mass?
  4. What causes objects to move or be set in motion?
  5. If traveling in a car with no seat belt, what would happen to you if someone suddenly slammed on the brakes? Why would this occur?
  6. When two objects collide what happens?
  7. Can a pendulum move an object at rest? How? Have you ever seen that happen? Explain.
  8. Why is it important to change only one variable at a time in an experiment or investigation?

• Feedback to Students

  
  
  1. Students will receive feedback while completing the activities outlined in the Explore and Elaborate sections. The teacher will circulate the room and ask questions checking for understanding. Ask questions such as:
     • Are there any other ways that would work? Why or why not?
     • What do you notice about the angle at which you drop the pendulum? String length? Bob mass?
     • What are the results?
  2. Throughout the lesson, students will be able to monitor their own progress; they will immediately know if they are designing a working pendulum because it will either move the mass appropriately based on the challenge guidelines or not.

ACCOMMODATIONS & RECOMMENDATIONS

• 
  

  Accommodations:

  • Students will work with partners or in mixed ability groups to construct their wrecking balls and assist with completing the attached recording sheets. Students needing assistance completing their recording sheets can dictate to a peer.
  • The attached vocabulary sheet can be copied and pasted into student journals rather than students copying by hand.
  • Technology and visuals are used for varying exceptionalities through the use of the digital resource provided in the engage and explore sections.
  • Students requiring an extra challenge may determine their own variables to change during the wrecking ball testing phase of the lesson.
• 
  

  Extensions:

  As an optional extension, have students respond to the following journal prompt: How could we change or expand this experiment? Explain your thinking.
• 
  Suggested Technology: Document Camera, Computer for Presenter, Internet Connection, Speakers/Headphones, Adobe Flash Player
• 
  

  Special Materials Needed:

  Summative Assessment:
  • Science journal or separate sheet of paper
  Engage:
  • Video link: http://safeshare.tv/w/olaxrCNyuq
  • Vocabulary attachment: one copy to project or copies for students that require additional assistance
  • Science journals
  Explore - per engineering team:
  • 3 large washers
  • length of string that can be measured to 15 cm
  • yard stick
  • unsharpened pencil
  • protractor
  • sticker or other marker to serve as the fixed starting point for each test
  • attached recording sheet, one per student
  • pencils to write with
  • Model buildings; see instructions provided in the Explore section
  Elaborate:
  • Class test site, see directions in Elaborate section
  • Student recording sheet
  Explain:
  • Science journals
  Extension (optional):
  • Science journals

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