Projectile Motion Learning Standards: Iowa Core Curriculum, Grades 4-5 ICC standards for (physical science) Essential Concept and/or Skill: Understand and apply knowledge of how forces are related to an object s motion. The motion of an object can be described by its position, direction of motion, and speed. That motion can be measured and represented on a graph. ICC standards for (inquiry) Use appropriate tools and techniques to gather, process, and analyze data. (3-5) ICC 21 st Century Skills (employability) Communicate & work productively with others Adjust to various roles & responsibilities What students will be doing: The students will be tasked to determine the best angle for projecting an object (ping pong ball) using a launcher. They will need to figure out how to conduct a fair test. They will hold trials and then consider the data to determine their solution. Through this experiment, students will gain further understanding and familiarity of: projectile motion, motion, force, gravity, angle, distance, and height. The Learning Cycle Steps and Teacher Notes: Engagement Exploration This video clip is an excellent way to introduce projectile motion. Students may want to watch the video more than once. Go for it! Questions to ask students after the video include the following: Do you think this is real or was it faked? Why or why not? How do you think they figured out where to put the pool? What if someone heavier went down the slide? Would they still hit the target? What if someone lighter went down the slide? Did they really need that wooden ramp? Why or why not? At what spot along the route was the person going fastest? Why did the person go up then come back down? We are going to be studying projectile motion. Can anyone tell me what this video had to do with projectile motion? http://www.arborsci.com/cool/the amazing water slide human projectile Materials: ping pong balls, launchers, measuring tape or meter sticks, masking tape, rubber bands of various sizes/thicknesses. Launchers may be purchased through this web site: http://www.teachergeek.com/projectile_launchers Ping_Pong_Ball_Launcher_Activity_10pk_2 html Teacher Notes: Set-up - Arrange materials in a fashion that makes distribution of materials and clean-up simple. Box lids or lunch trays work great to help keep materials organized. Before class, set up enough sets to allow students to work in groups of 2-3 students. After the Engage video and subsequent discussion, students will be primed to further explore projectile motion. Show students the materials tray before distributing materials to the class. This will help maintain their focus during teacher directions. Simply show students the materials, including the word launcher for the
name of the main device, perhaps asking students why they think this is called a launcher. Do not show them how to use the launcher - challenge them to figure this out on their own. It will become obvious they will be launching a ping pong ball. Be sure to include several rubber bands of various thicknesses on each tray and to tell students they will need to figure out how the rubber band is to be used, but that the launcher will not work without the rubber band. Resist the urge to tell kids how to attach the rubber band or work the launcher. Give them time to struggle and problem solve; they will be able to figure things out. Challenge students to mess around with the materials on their tray to try to discover three things: 1) how to work the launcher, 2) how to get the ping pong ball to go the farthest, and 3) how to make a ball go the highest. They will need to notice the angle setting of the launcher. Tell students there will be no need to record data as they explore, but to be prepared to share their discoveries. Allow students 15 or so minutes to work with their launchers, depending on their level of interest and focus. While students are exploring, move from group to group asking probing questions about what students have discovered. You may need to provide a hint or two about changing the angle of the device, but will find kids can figure it out with some skilled questioning. Bring student groups back together and have them share their discoveries. Ask students questions such as the following: What did you do to get your ball to go far? Did anyone notice how you were able to launch the ball with more force (pull the trigger back farther or add a tighter rubber band) How were you able to get the ball to go higher? (move the settings of the launcher so it was at a bigger angle) How were you able to get the ball to go farther? (Pull the trigger back farther and use a middle angle that is not too high and not too low.) Explanation Introduce the critical terms by first asking students what new words they believe are important in understanding this activity. Ideas will be strengthened if the class generates definitions where possible. Here are some of the important terms for this activity and samples of student generated definitions: projectile motion: motion in an arc pattern of up, then down. motion: any change in position from the resting position force: amount of push given to an object gravity: downward pull angle: steepness as measured in degrees by a protractor distance: how far from the launcher a ball travels as measured along the floor. height: the tallest point a projectile travels before starting to fall. Include a discussion designed to clarify main ideas and provide students with opportunities to think about the exploration activity in the context of the new terms. For example ask students why projectiles always come back down. (Initially a projectile s speed is enough to overcome the downward pull of gravity. But as the speed slows, the projectile s speed is no longer enough to overcome gravity and the object starts falling back to earth. It does
not fall straight down because it still has some energy that is moving it horizontally due to its initial speed and direction.) Materials: ping pong balls, launchers, measuring tape or meter sticks, masking tape, data tables (make copies of the launcher data table ) Challenge 1: Using the ping pong ball launchers, discover what angle is needed to get the ping pong ball to go the farthest. Elaboration Teacher Tips: Devise a way to share the challenge question with students. In this case, I am going to post the question on the overhead. Communicate to students how you want them to keep track of their findings. In this case, I will have students use an ipad to record what they discover using the popplett app, a keynote slide or a word processing doc. Pass out the materials to groups of three. Challenge students to assign a task to everyone in their group, rather than telling them exactly what those tasks are. Students will learn more about working together if they figure this out on their own. Having three students per group works well. You may need to help some groups assign tasks such as one student to launch and two students to accurately determine the landing spot and measure and record the distance. Give them a few minutes to discuss this, then call on some students to share their task assignments. Check with each group to insure they are on task and to see how they adjust their launcher to test a variety of launcher angles. As you circulate from group to group, ask questions to get students to make their own plan about how many trials they should carry out for each angle tested and how many different angles to test. Examples of questions include: Is testing the distance once at each angle going to give you enough data? Why or why not? (Hopefully students will realize that by doing more than one trial, you can make up for small differences in the way the shooter is pulled back or released or the chance occurrence of the ball traveling crooked. At least three trials at each angle will give more accurate data.) Which different angles do you think you should test? (Be on the lookout for students who decide to test every 2-4 degrees. Using changes that small will take longer than the class time will allow.) How will your group decide how many different angles you should test? Why? (While there is not one correct answer to this question, there are several logical approaches students may take. Some may keep increasing or decreasing the angle until they reach the point where it the ball goes the farthest. Then they can decrease or increase the increments by smaller amounts to determine the exact angle at which the balls travel the farthest.) Bring student groups back together and have them explain their findings in terms of how the angle affects the distance a ping pong ball can be launched. Encourage students to use the new terms introduced during the Explanation phase. Challenge 2: Explore the projectile motion computer simulation site to learn more about motion. Experiment with the variables that can be changed. Try everything. Make a list of everything you discover about motion, force, friction, and speed. In this case, I will have students display their discoveries in an interesting way using the ipad. How do your
findings compare to the discoveries you made using the ping pong ball launcher? Materials: Access to computers with Flash. This will NOT work on ipads since they do not have Flash. Simulation website: http://phet.colorado.edu/sims/projectile-motion/projectile-motion_en.h tml Evaluation Teacher Tips: You may need to prepare data tables for your students or provide information on which variables they should change. The variables they can change include angle, mass of object being fired, location of target, the size of the object being fired, the initial speed of the object being fired and the air resistance. You may want to assign one variable to each student group and have them report back to the class on their findings. Final Product: After testing of the new launcher, students collaborate to create a video to explain one component of projectile motion and will share this production with others. Students will be assigned a concept to illustrate and be given science terms that must be included in their presentation. In addition, their videos will use either computer simulations or the launchers themselves. Students reflect on the videos and make suggestions for improvement of future videos. Teacher Tips: Require students to write a full script in which everyone has a speaking role. Once you have checked the script, then supply the camera for recording. It works best to provide each student group with a set of requirements for their video. Samples are shown below under the heading Using Video to Assess Student Learning. Diversity Adaptation: One way to adapt the video assessment component of this activity to students of varying needs and abilities is by leveling the individual investigations by the complexity of the task involved. The table below shows one way in which this might be accomplished.
Handout for the Elaboration Phase: Data sheet for angle exploration (Challenge 1) Launcher Data Sheet Challenge 1 Group Members: What is your research question? Independent variable: Dependent variable: _ Name the variables you will hold constant: Data Table: Launch Angle and Distance Ping Pong Ball Travels Launch Angle (degrees) Trials Distance Traveled (m) trial 1 trial 2 trial 3 Average trial 1 trial 2 trial 3 Average trial 1 trial 2 trial 3 Average trial 1 trial 2 trial 3
Average Answer to your research question: Additional Information for the Evaluation Phase: Including group assignments and student handout for video scripting Group Number Students Student Group Assignments Filming Location 1 Sam P & Sam S Hallway Ping pong ball launcher 2 Phynnex & Daniel Hallway Ping pong ball launcher Main Materials Relationship Investigated Level of difficulty Angle vs. distance Force vs. distance Medium Complex 3 Nika, Lexi & Molly Hallway Straw launcher Force vs. distance Medium 4 Aubreigh & Katie Hallway Straw launcher Angle vs. distance Medium 5 Bennett & Leighton Classroom Computer Initial speed vs. distance Simple 6 Alex & Cullan Classroom Computer Roller Coaster Simulation (Friction) Simple 7 Aurion & Peyton Classroom Computer Angle vs. height Medium 8 Bianca & Gabi Classroom Computer Roller Coaster Simulation (steepness & loops) Complex The groups listed below stem from the table above, and provide specific information to each student group on their assessment tasks. Group #1: Materials: Launcher, protractor, ping pong ball Location: In the hallway Main Question: What angle causes the ping pong ball to go the farthest? Compare the distance a ball travels when shot at big angles (like 70 or 80 degrees), and a ball shot at small angles (like 10 or 20 degrees). What angle is best for distance? How did you discover this? Mention which variables you are keeping constant. Filming of this works best if you set up three separate launchers so their angles are all ready and you can film quickly. Film 3 different angles. What words you must include in your video: projectile motion, distance, angle, force, variable, and constant. Group #2 Materials: Launcher, ping pong ball, measuring tape
Location: In the hallway Main Question: How does the force you launch the ball with affect the distance it travels? Explain the purpose of this launcher Show how you can change the force you give the ball. We did not study this in class, so experiment with it first. Compare the distance a ball will go at different forces. Be sure to mention which variables you are keeping constant. What is your conclusion about force and distance? (What force is best for distance?) What words you must include in your video: projectile motion, distance, angle, force, variables, and constant. Group #3: Materials: Soda Straw Launcher, straws, clay and scissors Location: In the hallway Main Question: How does the length of the straw affect how far the soda straw travels? Compare the distance a soda straw travels as it is shortened. Explain which variables you will leave the same (initial force, amount of clay, angle) and which variables you will change (length of straw). What words you must include in your video: projectile motion, distance, launcher, force, angle, variables, and constant. Group #4 Materials: Soda Straw Launcher, straws, clay and scissors Location: In the hallway Main Question: How does the angle affect how far the soda straw travels? Compare the distance a soda straw travels as the angle changes. Explain which variables you will leave the same (initial force, clay and straw) and which variables you will change (angle). You will probably only have time to film 3 different angles. Pick a big one, the best one and a small one. What words you must include in your video: projectile motion, distance, launcher, force, angle, variables, and constant. What words you must include in your video: motion, speed, angle, gravity, friction. Group #5: Materials: computer with projectile motion simulation Location: In the classroom Main Question: How does the initial speed affect how far a launched ball will travel? Compare the distance a ball goes when its starting speed is changed. (Start at a small speed and gradually increase the initial speed) What initial speed is best for going the greatest distance? How did you discover this?
Be sure to mention which variables you will keep constant in your trials. What words you must include in your video: projectile motion, distance, angle, initial speed, variables and constant. Group #6: Materials: Computer and projectile motion simulation Location: In the classroom Main Question: How does the angle a ball is shot affect the distance the ball travels? Compare the distance a ball goes when shot at big angles versus small angles. What angle makes the ball go the farthest? How did you discover this? Be sure to mention which variables you will keep constant in your experiment. Words you must include in your video: simulation, projectile motion, height, distance, angle, variables, and constant. Group #7: Materials: Computer and projectile motion simulation Location: In the classroom Main Question: How does the shooting angle affect how high a ball will go? Compare the height a ball goes when shot at different angles. Explain which variables you will leave the same (initial speed, mass, type of object) and what you will change. What words you must include in your video: projectile motion, height, initial speed, and angle, variables, constant.
Student Record Sheet: Names: Projectile Motion Video Script Introduce yourself: State your Question: Show your Materials: Demonstrate the Experiment: Say which variables you will keep constant: Say which variables you will change:
State your Conclusion: