Catapult (Anomalous Data Lab, Double Period)

NJ Core Curriculum Standards

CCS Number / Topic / Description
5.1.12.A.2 / 5.1 – Science Practices
A – Understand Scientific Explanations / Interpretation and manipulation of evidence-based models are used to build and critique arguments/explanations.
5.1.12.B.2 / 5.1 – Science Practices
B – Generate Scientific Evidence Through Active Investigations / Mathematical tools and technology are used to gather, analyze, and communicate results.
5.1.12.B.3 / 5.1 – Science Practices
B – Generate Scientific Evidence Through Active Investigations / Empirical evidence is used to construct and defend arguments.
5.1.12.D.1 / 5.1 – Science Practices
D – Participate Productively in Science / Science involves practicing productive social interactions with peers, such as partner talk, whole-group discussions, and small-group work.
5.1.12.D.2 / 5.1 – Science Practices
D – Participate Productively in Science / Science involves using language, both oral and written, as a tool for making thinking public.
8.2.12.C.3 / 8.2 – Technology Engineering, Education, and Design
C – Technological Citizenship, Ethics, and Society / Evaluate the positive and negative impacts in a design by providing a digital overview of a chosen product and suggest potential modifications to address the negative impacts.
8.2.12.E.1 / 8.2 – Technology Engineering, Education, and Design
E – Communication ad Collaboration / Use the design process to devise a technological product or system that addresses a global issue, and provide documentation through drawings, data, and materials, taking the relevant cultural perspectives into account throughout the design and development process.

What Students Should Know

  • Kinematics
  • Constant velocity
  • Constant acceleration
  • 2D projectile motion
  • ISLE
  • The Engineering Design Process

Goals of the Lesson

Conceptual / Quantitative / Procedural / Epistemological
How does your catapult differ in results depending on projectile? Why? (Assumptions matter) / Be able to measure the range of projectile. / Be able to use the Engineering Design Process to direct assembly, testing, and revising design. / How do scientists deduce the cause of something in anomalous data experiment?
What kind daily activities is the catapult related too in terms of same physics? / Be able to calculate unknowns related to your projectile’s time in flight based off of empirical data. / Be able to work with materials given (be able to measure physical quantities using a meterstick or other tools). / How can I improve my design and make my device functional and economical in materials and/or energy use?
At what angle given you the greatest range? (Trick question) / Be able to calculate the difference between expected range and actual range. / Be able to work effectively with others. / How can I figure out what types of physics are needed to make quantitative predictions?
What kinds of engineering disciplines are involved in making a catapult? / Be able to calculate experimental uncertainty. / Be able to plan ahead before construction. / In what ways does the Engineering Design Process contribute to learning?

Important Details/Connections

Physics Content

  • Kinematics
  • Constant acceleration of 9.8 N/kg toward Earth
  • Trigonometry
  • Vectors
  • Kinematics formulas
  • Assumptions about air resistance

Real Life Connections

  • Sports, throwing a ball is not the same will all balls
  • Defining material needs and uses
  • Missile targeting
  • Wind resistance
  • Airplane trips/turbulence

Potential Student Difficulties

  • Figuring out why different projectiles go different distances, not within uncertainty
  • Being able to have a stable, repeatable distance achieved with the same projectile
  • Calculating all forms of uncertainty
  • Being able to build a well designed catapult in the time given
  • Students may not know what kinds of engineering is involved
  • Students may have difficulty modifying design in a systematic way

Resources

Environment

  • Large work tables for groups of 4-5 students
  • Large areas on floor for testing catapults

Equipment

  • Tape, popsicle sticks, glue, cardboard boxes, rubber bands, pencils, plastic spoons
  • Cotton balls, cotton balls wrapped in tape
  • Meter sticks, stop watches

Lesson Description

So you remember yesterday how we took a look at that video (PAER projectile motion video and we came to the conclusion that the 45 degree angle gave the largest x displacement. What else did we figure out? (That the time in flight is independent of the angle at which the projectile was launched, as long as it is on the same setting.) So what we are going to do today is build our very own catapults and see if we get the same results. I have all of the materials on this table, I want every group to come up and look for a minute, then go back and take 5 minutes to roughly plan what you want to do. I want to point out that in the Engineering Deign Process I have just given you the problem, yesterday and all of this unit we have been researching this topic, and right now you are developing solutions and choosing the best one.

Once you have come up with a design you want to try come get the materials and be sure to take one of each type of projectile. We are going to be using cotton ballsand cotton balls wrapped in tape as out projectiles. As you work make sure someone in the group is recording your design and another person is taking measurements of the catapult.

Now that you have a catapult, and I am sure you have already tested it. I just want to make sure. Take one of your projectiles and launch it. If something is not working, take another 10 minutes to fix it. If you want it to launch at a different angle, go farther, or make your catapult more stable and results more repeatable also make adjustments now.

Now according to what happened in the video yesterday, what would you expect to happen? (That the time in flight for everything should be the same; should all go the same distance.)

Now I want everyone to start taking x displacement data for each of the projectiles as well as total time in air. Do your best in taking measurements and do not forget to do multiple trials. You will be calculating the uncertainty in all of this later. Make sure that all of your data is neat and organized and leave room for calculations.

I want you to take 10 minutes and calculate your uncertainties. After all, if we want to know if these times agree, we have to know the uncertainty in our measurements.

Now that you have all your results with uncertainty, do they agree? If not why not? I want to discuss this as a class, so each table should be contributing to the discussion. (If talking stagnates, drop in questions about uncertainty, assumptions, materials, simplifications in the physics, etc…)

Now if you think the data did not agree, take another minute to make last minute changes to your design that you think would rectify the problem. Test quickly and see if your number agree.

Time Table

Clock Reading During Lesson / Title of Activity – Connection to Goals / Students Doing / Teacher Doing
Period 1
0-6 minutes / Goals and viewing materials / Listening to teacher, going up to see materials available. Planning what kind of catapult they will make. / Giving goals for the day, handing around materials.
6-35 minutes / Building Catapult / Building catapult. / Helping students build the catapults.
35-45 minutes / Testing and Redesign / Testing catapults, redesigning if necessary. / Helping students, making sure that those done are set up for taking data and have stable data.
45-60 minutes / Taking Data / Making predictions about time in flight and distance, then taking data in multiple trials for each projectile. / Asking students to make predictions, reminding them on taking data procedure and checking organization of data.
60-70 minutes / Calculating Uncertainty / Calculating instrumental and random uncertainty in data. Comparing results to see if prediction was supported. / Checking to make sure that all tables can calculate uncertainty correctly, and know all uncertainties to calculate.
70-85 minutes / Discussion / Discussing why times did not agree or distances. Identifying assumptions. Identifying parts of catapult to redesign if necessary. / Leading discussion with questions, allowing students time to redesign catapults to try and refute evidence.
85-90 minutes / Cleaning Up / Cleaning Up / Cleaning Up

Formative Assessments

  • Do students remember important points of video from day before?
  • Are students able to come up with a design?
  • In building the catapults, are students working together or against each other?
  • Do students take the opportunity to test and redesign their catapults?
  • Can students organize data?
  • Can students take measurements with appropriate tools?
  • Do students know how to calculate instrumental and random uncertainty?
  • Can students identify assumptions/simplifications?

Homework

Write a 2 page (double spaced) paper, not formal, on what aspects are not obvious about this, and discuss at least 3 other real-life examples of how engineers must be wary of these things, and what you think they should do to minimize any error in their predictions. You may not use a catapult as one example, examples must be modern.