Catapult and Trebuchet Handbook - WikispacesCatapult+Packet.pdf · 01pHp Catapult Packet.docx 3...

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Hanover High School Physics

Catapult and Trebuchet

Handbook

2016-17

http://www.ghsteched.com/catapult2.jpg http://n-pass.edc.org/archives/Trebuchet%20image.gif

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Past Results and Records Large Scale

2016 Catapult Sarah Bibeau & Lane Celone 87.8’ 2015 Catapult Konrad Mitchell 62.2’ 2014 Catapult Matt Leskovar 98.9’ 2013 Catapult Matt Couture, Ryan O’Rourke 58.0’ 2012 Catapult Jonathan Gougelet, Sam Shapiro 94.0' 2016 Trebuchet Niels Kingston & Ebben Whitehair 184.9’ 2015 Trebuchet Jack McNamara 81.9’ 2014 Trebuchet Max Greenwald, Toby Reynolds 33.5’ 2013 Trebuchet Zach Estes, Galen Richardson 154.3’ 2012 Trebuchet Greg Stragnell, Cole Flickenger 227' 9"

Small Scale

2016 Catapult Jake Laser 28.5’ 2015 Catapult Reilly Decker 23.8’ 2014 Catapult Sumner LeBarron-Brien 31.4’

and Connor Nagle 2013 Catpult Jesse Brown, Addison LaRock 46’

2016 Trebuchet Marco van Gemeren 12.3’ 2015 Trebuchet Sophie Kelly and Jonas Taenzer 2.1’ 2013 Trebuchet Ricardo Addante 17.6’ 2012 Trebuchet Katherine Bradley 12.6’

Current Record

Results are the average of top 5 of 6 official firings performed at the Weapons Showcase at Hanover High School.


Catapult and Trebuchet Contest Guidelines q Your catapult or trebuchet will launch a foam ball provided by your

teacher. The ball may not be altered in any way. q Catapult builders will be given an elastic band as an energy source. This

band can be cut but additional elastic material cannot be added to your catapult. You may request a new band to replace yours, if it breaks or gets stretched out.

q Trebuchets must use a sling that releases the ball completely, with no part of the sling attached to the fired ball.

q Aside from the ball and band, you supply the materials for your weapon.

Small Scale q The finished trebuchet or catapult must fit within a 0.2 x 0.2 x 0.3 m box.

It must be able to fit in a box of those dimensions prior to firing. A firing arm may swivel "out" of this box during firing, but the firing arm must fit into the 0.2 x 0.2 x 0.3 meter box when "loaded" in the firing position.

q The trebuchet may use a counterweight of up to 500 g. Weights may be signed out for use at home. Catapults use the rubber band supplied by your teacher, which can be replaced if needed. Both throw a foam practice golf ball.

Large Scale q The size of the catapult is limited to 1 x 1 x 2 meters. It must be able to

fit in a box of those dimensions prior to firing. A firing arm may swivel "out" of this box during firing, but the firing arm must fit into the 1 x 1 x 2 meter box when "loaded" in the firing position. The catapult may fire in any position (sideways, upright, or horizontally).

q The trebuchet may use a counterweight of up to 30 pounds. You supply these weights. Catapults use 1 meter of physical therapy band, supplied by your teacher, which can be replaced if needed.

q Both catapult and trebuchet fire a foam baseball, supplied by your teacher.

Firing Mechanics q All weapons must have a loading mechanism that will remain loaded

without human intervention.


Performance Benchmarks Part of the points for this project depend on how well your weapon performs. The table below shows the distances benchmarks for each contest. Details of the awarding of performance points are in the rubrics at the end of this handbook.

Benchmark #1 5 performance points

Benchmark #2 5 more performance points

Small Trebuchet 2 feet 10 feet

Small Catapult 10 feet 20 feet

Large Trebuchet 10 feet 50 feet

Large Catapult 25 feet 50 feet Distances used for official contest results and performance points are the average of the 5 best of 6 official firings of your weapon at the HHS Weapons Showcase.

Safety q You are expected to work safely when constructing your catapult or

trebuchet. This includes wearing gloves and eye projection. q Parents will be asked to sign a letter of permission, so they are aware of

the project and risks involved. q Using a different elastic band, weight, or projectile is NOT permitted and

will result in substantial grade penalty. This is for your safety.


Due Thurs.

4/6 or before

Start NOW!

Due Friday 4/28

CATAPULT or TREBUCHET Checklist Your Goal: To design, build, and test a catapult or trebuchet. To Get Started q Read the Catapult and Trebuchet Handbook and

learn what the project involves. Study the rules and dimensions required. Use this information to…

q Write your Project Proposal using the doc in Schoology. o Be specific and detailed, showing that you understand the steps and

requirements of the project. o Meet with your teacher if you have questions or need help. o Your proposal is worth 10 POINTS as a 4th quarter HW assignment.

Before Construction q Find and Read references about your chosen weapon.

o What is the source of stored energy? o What makes an efficient trebuchet or catapult? o What variables can you change to improve your

weapon? o How can you maximize the range?

q Find a software simulator and experiment with the dimensions and variables of your weapon. Try to use the masses or elastic potential energy for the small- or large-scale weapons given in the contest guidelines. Simulation details are supplied on a later page of this handbook. o For catapults you will use HHS Super Catapult Simulator, linked in the Capapult

Folder in Schoology. o For trebuchets, you should use free software tools

specifically designed for trebuchets. You can try VirtualTrebuchet at http://www.virtualtrebuchet.com/

o Make at least 3 alterations to your simulation to improve the firing range and efficiency of your weapon. Keep your alterations within the guidelines of the project for size, mass, and ball thrown.

o Print out your results for each revision, showing maximized range and efficiency, to include in your paper. Annotate your print-out to show what the dimensions and conditions were. Write a paragraph describing each of your revisions to optimize the range and efficiency of your weapon. This will be useful when you write your final paper.

r Write Progress Report #1 o Use the doc in Schoology. o It is worth 5 POINTS as a 4th quarter HW assignment. o The more you get done, the higher your grade!

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Due Friday

5/12

Catapult or Trebuchet Construction q Choose a scale for your catapult q Gather materials q Begin Construction. q Design loading and firing mechanism.

o A large scale catapult or trebuchet will fire a foam practice baseball.

o A small scale catapult will fire a foam practice golf ball. o Your catapult or trebuchet must have a loading mechanism that will remain

loaded without human intervention (i.e. you cannot simply hold the “slingshot” or weight and release it, to fire your weapon).

o If making a trebuchet, research and design the sling. This is sometimes the trickiest part.

q Label your weapon with your name(s). q Practice and test

o Make sure your weapon can fire consistently and be loaded quickly and easily. q Schedule a conference with your teacher to ask questions, check your progress, and

get help. q Write Progress Report #2

o Use the doc in Schoology. o It is worth 10 POINTS as a 4th quarter HW assignment. o You should have more work done since the first progress report!

Weapon Testing and Analysis q Record the range (horizontal distance) for at least 10 test firings. q Your device must be transported to school and fired for an “official” distance

measurement at the catapult showcase on the turf field. q Complete a Conservation of Energy and projectile analysis of catapult or trebuchet

for final paper. Details are in a later page of this handbook. o Calculate or measure the stored potential energy of the loaded weapon. For a

trebuchet, this is gravitational potential energy. For a catapult this is elastic potential energy.

o Calculate the velocity of the ball, as it leaves the weapon, using conservation of mechanical energy.

o Use projectile analysis to calculate the expected range of your throw from its initial velocity and angle.

q Calculate the actual efficiency of your catapult. o Use an average value of the measured range of your

catapult to calculate the velocity of the ball as it leaves the weapon.

o Calculate the KE of the ball at the start of the throw from this velocity.

o Calculate the actual efficiency from actual KE and the stored PE.

o Compare this to the efficiency of your simulation by percent difference.

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Final Papers

are due

Friday 6/2

Presenations start Wed. 5/24

Oral Presentation q Outline and organize o Introduction o Design and construction process o Preliminary test results o Conservation of energy and projectile analysis, efficiency o Conclusion o Demonstration of throw, if possible. o Make visually interesting o Communicate information clearly

q Check presentation rubric and revise, if needed. q Practice your presentation

Final Paper q Introduction

o Goals of project o Physics background on weapon forces, energy transformations, construction. o Steps and aspects of project

q Materials and Methods o Details of actual design described in paragraphs o Clear technical drawing with dimensions, materials, and all views (sides, top, and

front). Can someone duplicate your weapon from your drawings and text? q Results

o Simulation results with printouts, described in paragraphs o Weapon testing results in table, described in paragraphs o Description of changes made to improve performance o Conservation of energy, projectile, and efficiency analysis with clear calculations

q Conclusion o Did your weapon perform as expected? Where was mechanical energy lost? o Did your weapon illustrate conservation of energy and projectile motion? o How could you improve your design or construction to make it work better?

q References o Must be complete references, clearly cited in MLA or APA format o Must show depth and breadth of research, 5 references minimum o All images, simulation software, and this packet1 should be referenced.

q Format o Typed, spell checked, grammatically correct, readable o Clearly organized with sections labeled,

q Check with paper rubric and revise, if needed. Weapons Showcase q Bring catapult to school to perform in Weapons Showcase. Tentative

date and time is Monday 6/5, 1-3 p.m. Kick a#$* in competition. q Take your catapult and all supplies home, leaving field totally clean. q Add your final results and standings to your final paper. 1 Hair, Sally. Hanover High School Physics Catapult and Trebuchet Handbook. Hanover, NH, n.p., 2017. Print.

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Physics Project Proposal Form Please complete on Schoology, not on paper. Thank you.

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Name(s) _____________________________________________________ Class Period(s) 1 2 3 4 5 6 7

r Independent Topic ______________________________ r Catapult Trebuchet (circle one) Large Scale Small Scale (circle one) r Amusement Park

ð Proposals are due Thursday, April 6, or before. Late proposals receive no credit.

ð Submit one proposal for the project, if you are working with a partner.

ð For catapult, or amusement park, please show that you have read the instructions and understand the project's steps and requirements.

ð Explain your project by discussing the following in clear, well-organized, and detailed paragraphs. Please complete this in the doc on Schoology. Questions to be answered or ideas to be investigated: ___________________________________________________________________________________________________________________________________________________________________________ In your project will you: measure something build something both What will you measure? __________________________________________________________________________________________________________________ What tools or apparatus will you use for your measurements or data collection? __________________________________________________________________________________________________________________ Explain how the data will be measured. _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Physics Project Proposal Form Please complete on Schoology, not on paper. Thank you.

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What apparatus will you build? (If you are not building anything, leave this blank) _________________________________________________________ How do you propose to design, build, use, and test your device or apparatus?

(If you are not building anything, leave this blank) _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ How will you analyze the data you collect? What theories, equations, or calculations will you use? ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Can you compare your results to known values or Hanover High records? Yes No What are these values or records? _________________________________________________________________________________________________________________________________ What safety considerations are part of your project planning? ___________________________________________________________________________________________________________________________________________________________________________ Is there anything you want to ask your teacher about your topic? ___________________________________________________________________________________________________________________________________________________________________________


Catapult Simulation and Optimization While a catapult has fewer moving parts than a trebuchet it can be just as complex to get the details right. Things to consider are the length of the arm, the direction the elastic pulls the arm, and what point on the arm the tension is applied to. Also it’s important to consider the release and firing angles.

Creating a catapult model with HHS Super Catapult Simulator 1. Find the simulator by clicking on the link in the Catapult Folder on Schoology. 2. The simulation allows you to vary the release angle, the launch angle, the

elevation of the cup, the location of the pivot, and the attachment of the elastic band.

3. Test the effect of each variable on the range of the projectile by modifying the initial conditions, changing one variable at a time and optimizing the distance of the throw. Try to ask and answer questions like • What is the best place to position the elastic on the fixed and rotating arm? • Does it matter how far the cup is pulled back before release? • What is the optimal angle to release the ball?

4. Keep careful records of the changes you make and the range of the projectile to optimize at least 3 variables, one at a time.

5. Record variations and distances of shots. Print screen shots to show your optimization and final results for your paper.

6. The simulation catapult is a schematic design and you can modify it. Just keep in mind the variables you optimized and apply what you learned to your design.

Trebuchet Simulation and Optimization A trebuchet has lots of moving parts and changing the ratios between these parts can change the height and speed of the projectile. Your challenge is to find the optimum conditions to throw the ball as far as possible without surpassing the size restrictions. There are many trebuchet simulators online. One that is easy to use is http://www.virtualtrebuchet.com/ This simulation allows you to change many measurements of the trebuchet then simulate the flight of the projectile. Change different measurements one at a time to find the

optimum values. Remember the size requirements: --The trebuchet can’t be more than a meter long or two meters high when loaded. --The counterweight can’t exceed 30 pounds or 500 grams. --Weigh and measure the ball and use these values in your simulations.

The Sling One challenge in designing a trebuchet is making a proper sling. Look for online sources with different sling designs. Try http://www.siege-engine.com/SlingsAndPouches.shtml or search online if you need ideas.

http://www.real-world-physics-problems.com/images/physics_trebuchet_3.png


Catapult Calculations Your paper should include clear calculations. Your presentation should also summarize the results and explain the concepts of the calculations to the class.

Conservation of Energy 1. Calculate or measure the stored potential energy of the loaded

weapon. q For a trebuchet, this is gravitational potential

energy. GPE = mgh. Measure the mass that falls and the distance it will fall. This is the stored energy.

q For a catapult this is elastic potential energy. You can determine the spring constant of your band using Hooke’s Law (F = -kx), then calculate EPE = 1/2 kx2. Measure the force on the band (F) and the distance it stretches (x). You should graph F vs. x and find the slope (k). The EPE will be the stored energy for the maximum stretched distance, x.

OR q You can measure the force applied to the band

(borrow a spring balance) vs. the distance the band is pulled. Then you can calculate work from the graph of F vs. x. This should be roughly linear and the area under the curve is the work done to stretch the band. The work done equals the stored potential energy.

2. Use Conservation of Energy to find the initial velocity of the ball.

q If mechanical energy is conserved, the stored energy will equal the kinetic energy of the ball as it leaves your weapon. (PE = KE = 1/2 mv2) Solve for v.

Projectile Analysis 1. Use the initial velocity from conservation of energy and the

measured or estimated angle of release to calculate the range of your projectile.

q The range formula will help you.

€

R =v0

2

gsin 2θ

q Compare the calculated range to the average actual range from several throws by % difference.


Efficiency 1. Calculate the actual initial velocity of your projectile

from the actual range. q Work backwards, using the range formula. Solve for vο

and use your average experimental range (R) and angle of release (θ).

q Now calculate the actual kinetic energy of the projectile from its initial v and mass.

2. Compare the calculated KE from your actual range to

the PE you determined from your Work, EPE, or GPE. q Calculate the efficiency as

€

Efficiency =Actual KE calculated from measured range

Calculated PE from GPE,W,EPE×100%

3. If your simulation included an efficiency, compare your calculated

efficiency value to the simulation efficiency by % error.

https://afsharphysics.files.wordpress.com/2013/09/projectile.jpg


Catapult Project Progress Report #1 Please complete on Schoology, not on paper. Thank you.

Name(s): Project Topic: Date: Write a paragraph or two summarizing your work on the project, so far. Include an overview of any measured results you have obtained. This will be typed in the Google Doc and turned in on Schoology. Have you found and read the background information on catapults? Y N Have you done library or on-line research and started a bibliography? Y N # of references: Have you worked with HHS Super Catapult, Virtual Trebuchet, or other software to simulate your weapon?

Results achieved: Y N Have you decided on a size of catapult to build? Y N Size: Have you finalized your catapult design? Y N Describe:

Have you gathered materials for building your catapult? Y N Have you met with any difficulties? Y N Have you solved these difficulties? Y N Explain: Please write a list of the things you need to do to complete your project.


Grading Rubric Grading Scale Research Book, online research, started bibliography

1 Yes, with more than one reference.

0.5 Started, one reference

0 No Research

Experimental Design Clear plans for experiments, simulations begun, design of catapult or other device underway.

1 Yes, great progress!

0.5 Some progress

0 No design progress

Experimental Materials Gathered building materials, borrowed equipment from Physics Room


0.5 Some progress

0 No progress with materials or equipment

Other Progress Problem set for amusement park, building for catapult or trebuchet, experimenting for independent projects.


0.5 Some progress

0 No progress in other areas

Planning Clear and comprehensive list of what needs to be done to complete the project.

1 Yes, very clear and complete.

0.5 Clear but not complete

0 Missing

Total: 5 points


Catapult Project Progress Report #2 Please complete on Schoology, not on paper. Thank you.

Name(s): Project Topic: Date: Write a paragraph or two summarizing your work on the project, so far. Include an overview of any measured results you have obtained. This will be typed in the Google Doc and turned in on Schoology. Have you found and read the background information on your weapon? Y N Have you done library or on-line research and started a bibliography? Y N # of references: Have you worked with HHS Super Catapult, Virtual Trebuchet, or other software to simulate your weapon?

3 properties or dimensions varied: Y N Optimized ratios or dimensions:

Have you finalized your catapult or trebuchet design? Y N Describe:

Have you completed a scaled drawing of your design? Y N Please attach Have you gathered materials for building your catapult or trebuchet? Y N Have you started building your catapult or trebuchet? Y N Have you finished building your catapult or trebuchet? Y N Have you met with any difficulties? Y N Have you solved these difficulties? Y N Explain: Please write a list of the things you need to do to complete your project.


Criteria Grading Scale Research Book, online research, started bibliography

2 Yes, with more than one reference.

1 Started, one reference

0 No Research

Experimental Design Clear plans for experiments, simulations begun, design of catapult or other device underway.


1 Some progress

0 No design progress

Experimental Materials Gathered building materials, borrowed equipment from Physics Room


1 Some progress

0 No progress with materials or equipment

Other Progress Problem set for amusement park, building for catapult or trebuchet, experimenting for independent projects.


1 Some progress

0 No progress in other areas

Planning Clear and comprehensive list of what needs to be done to complete the project.

2 Yes, very clear and complete.

1 Clear but not complete

0 Missing

Total: 10 points


Catapult or Trebuchet Project Presentation Grading

Introduction o Problem defined, questions posed, goals of project outlined. o Review physics background of project learned in class. o Explains new physics concepts to the audience.

5

Materials and Methods o Details of the experimental design are described and illustrated. o Diagrams and images show all views (top, front, & sides) to fully illustrate the

design of the apparatus. Show weapon to class, if possible. o Description of decision-making process, including

o alternatives considered. o research methods. o reasons for any modification.

5

Data and Results o Data and results summarized in well-organized tables and clearly-labeled

graphs. o Data, results, and calculations clearly described and fully presented. This

includes simulation results, preliminary distance data, energy and projectile calculations, and efficiency.

5

Conclusion o What distance do you predict your weapon will throw? o How could you improve your design to make it work better? o What would you do if you had more time? What factors contribute to the success

and efficiency of your weapon? o Report any new or unexpected conclusions or discoveries. o Sources of error described and discussed, including

o type of error and whether random or systematic. o calculate or estimate magnitude of error using percent error, if possible.

o Summarize physics concepts learned and illustrated in project.

5

Visual Aids o Clear. o Engaging. o Beneficial to audience attention and understanding.

1

Answers to Questions o Clear, thoughtful, accurate, and complete. o Shows good understanding and knowledge of project topic.

2

Overall Clarity o Organized. o Smoothly presented. o Clearly communicated.

2

TOTAL

25


Catapult or Trebuchet Project Final Paper Grading Introduction

o Describes problem, questions, and/or goals of project. o Reviews physics background of the topic learned in physics course. o Explains new physics concepts needed to understand project. o Includes figures, diagrams, or examples as needed for clear explanation.

10

Materials and Methods o Details of the experimental design are described o All materials listed. Equipment named correctly. o Scale diagrams of all views of weapon (sides, front, and top) with dimensions. o Includes safety precautions. o Description of decision-making process, including

o alternatives considered, o research methods, o reasons for any modification.

10

Data and Results o Data and results fully presented in

o well-organized tables. o clearly-labeled graphs.

o Sample calculations included. o All data, results, and calculations described in clear text. o Addresses all aspects of project

o simulation results o distance data o energy, projectile and efficiency analysis

o Final results summarized clearly, in text and table if needed.

10

Conclusion o How well were questions answered, problems solved, or goals met? o How did results compare to expected results or theoretical values? o Sources of Error, type, random or systematic, calculate % error or other value o How could you improve your design to make it work better? What would you do

with more time? o What factors contributed to the efficiency and success of your weapon? o Summarize physics concepts learned and illustrated.

10

Bibliography o At least 5 sources. o Clear and complete citations in APA or MLA format. o Parenthetical citations in text of paper o All images, figures, and photos credited.

4

Format o Typed, turned in on Schoology. o Spelled Checked, no grammatical errors. o Well organized, readable.

2

Understanding of Physics o Communicates solid understanding of physics concepts without vagaries,

misconceptions, or mistakes.

4

TOTAL

50

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w.hcpl.lib.tx.us/sites/default/files/catapult_0.jpg


Performance Points for Catapults and Trebuchets

Criterion Your Points

Points possible

Simulation completed and clearly documented in paper. 5

Meets all contest requirements o Dimensions o Weight or Band o Ball o Firing Mechanism

5

Performed 6 official firings at Weapon Showcase 5

Meets Contest Benchmark #1 for Average of best 5 of 6 official firings

5

Meets Contest Benchmark #2 for Average of best 5 of 6 official firings

5

Total 25


Final Project Overall Grade

http://etc.usf.edu/clipart/44700/44746/44746_graduate_sm.gif

Class Presentation (25% of total) 25

Final Paper (50% of total) 50

Performance Points (25% of total) 25

Bonus for working without a partner +5

Bonus for breaking HHS record +5

Deductions

Attendance (-5 per unexcused absence)

Lateness (-5 per day late for paper)

Materials left at school (-5 to -10)

TOTAL 100

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