DO NOWSept 16

DO NOWSept 16

• Work with your Catapult teams.• BRAINSTORM for 10 minutes about websites

and ideas you have found through your RESEARCH.

• Ask yourselves which part of the project will be most challenging for you.

• GET ORGANIZED!!!

CATAPULT CHALLENGE

STEM Trimester 1 2013

CATAPULT CHALLENGE TEAMS

• You will work in your teams to complete this project.

How to build a catapult in eight easy steps

• Watch the following video documenting the tedious and very demanding process of building a medieval trebuchet.

• These boxes are labeled with each step of the EDP.

DO NOWSept 17

• Which velocity is most important when designing a catapult?

• Explain your answer.

DO ANSWERED SEPT 17

• Both Vx and Vy are equally important. • Equal horizontal and vertical velocities will provide the

projectile with the maximum distance in travel.

• If Vx is greater than Vy, the projectile’s trajectory will push it downward into the ground.

• If Vy is greater than Vx, the projectile’s trajectory will push it upward causing it to lose energy.

• How do you achieve equal horizontal and vertical velocities?

MEDIEVAL SIEGE

• http://www.youtube.com/watch?v=5WDiW1WDyrA

DO NOW Sept 20

• Take out your Measurements Worksheet and Scale Drawings

AGENDA Sept 20

• BIG QUESTION: How can energy be used to launch a projectile?

• DO NOW

• 1. Review Measurements and Scaling• 2. Catapult Physics – Forces• 3. Conclusion of Medieval Siege Video Clip• 4. Catapult Teams – Presentations

THE PHYSICS OF A CATAPULT

• Catapults use stored energy to hurl a projectile without the use of an explosive charge. The three primary energy storage mechanisms are tension, torsion, and gravity. (Real-World Physics)

TENSION

• Tension is the pulling force exerted by a string, cable, chain, or similar solid object on another object.

• Tension is the opposite of compression force.

• Measured in Newtons (N).

• PE when drawn or taut (C)• Energy = 0 at rest (B)• KE when released (A)

Examples of Tension

• Bows and Crossbows

• Composite bow is a traditional bow laminated together.

• When the bow is drawn, the sinew (stretched on the outside) and horn

• (compressed on the inside) store • more energy than wood for the • same length of bow.

Examples of Tension

• Muscle Fibers create tension during a muscle contraction.

• Muscle fibers slide across one another producing tension.

TORSION

• Torsion is the twisting of an object due to an applied torque.• Torque is a rotational force.

• An object tends to rotate about a fixed object.Torque = Force x Lever Arm Distance

Torque

Examples of Torsion

• Flexible elastic object that stores mechanical energy when it is twisted.

• Torsion bar suspensions

Examples of Torsion

Counterweight

• A counterweight is an equivalent counterbalancing weight that balances a load.

Counterweight

When a counterweight is greatly overbalanced on one end of a lever, it can produce large amounts of energy.

Potential Energy vs. Kinetic Energy

Counterweight is not moving vs. moving.

The Mangonel Catapult

• Catapults work by storing energy in twisted ropes.• They function much like an archery bow.• The tension stored is released as kinetic energy.

The Trebuchet

• The trebuchet uses a counter-balance weight to rapidly rotate the throwing arm when the weight is released.

Generating Energy

• The twisted rope is commonly referred to as a torsion bundle.

• It consists of several lengths of rope with the arm inserted in between them.

• The rope is then twisted manually on both sides of the arm using levers.

• Upon release, the torsion bundle rotates the arm at high speed, launching the payload.

DO NOW Sept 23

• List the eight steps of the EDP.

•Which step do you believe is the most important to the success of your Catapult Challenge? • Explain your answer.

DO NOW ANSWERED

AGENDA Sept 23

• Big QUESTION: How do the steps of the EDP assist you in building a successful catapult?

• 1. DO NOW• 2. Project Presentations: DUE THURSDAY SEPT 26• ALL TEAMS MUST BE PREPARED TO PRESENT

ANY TEAM NOT READY WILL LOSE 20% of THEIR GRADE.

• 3. Media Center• 4. Practice your presentations!!!

Media Center Expectations for Sept 23

• 1. All teams should finish their presentations first.• 2. I will check with every team in the Media Center to make

sure you are on task.• 3. I am looking for completed presentations including

diagrams, video clips, animations, as well as an order of presentation. Slides each team member will be presenting. Know your information. PRACTICE. Being unprepared will affect your grade.

• 4. All team members must have a copy of the presentation. Being ABSENT is NOT an EXCUSE!!!

• 5. Continue with your RESEARCH. BE ORGANIZED!

DO NOW Sept 24

• You are asked to design a new touring bicycle for the US Postal Service team.

• Describe how you would go about this process. Use EDP as a framework

DO NOW ANSWERED

• Find out if the riders have any specific requests (Step 1)

• Determine a budget, building materials, and how quickly they need it (2).

• Research existing models and share new ideas. Collect data on what works (3).

• Choose a few ideas to develop. Different frame materials (aluminum, titanium, carbon fiber). Notes and drawings (4)

• List pros and cons of each bicycle design (5).• Pick the best idea with your team. Use

multiple parts from different ideas (Frame material from one idea and frame geometry from another idea 6).

• Build a bike. Does it all fit together? (7)• Get out and RIDE! Make improvements based

upon rider feedback, input, suggestions (8)

AGENDA Sept 24

• BIG QUESTION: How does engineering evolve to build safer machines?

• 1. DO NOW• 2. Presentations DUE THURSDAY SEPT 26• 3. The duty of responsible engineering• 4. Introduce New Engineering Critique Project• 5. Closing Thoughts and Review

Engineering

• The role of the engineer is to respond to a need by building or creating something along a certain set of guidelines (or specifications) which performs a given function.

• Devices, plans, or creations should perform its function without fail.

Engineering

• Engineers must struggle to design in such a way as to avoid failure, and, more importantly, catastrophic failure.

• Result in loss of property, damage to the environment, and possibly injury or loss of life.

• With analysis and study of engineering disasters, modern engineering designers can learn what not to do and how to create designs with less of a chance of failure.

Engineering Disasters

• http://www.youtube.com/watch?v=SmyLgg15aKU

• 8:52

Modern Engineering

• What are the general opinions and fears of the public?

Disasters are identified by the public’s perception of risk.

Perception of Risk

• In 1992, roughly the same number of fatalities occurred (in the United States) in transportation accidents involving airplanes (775), trains (755), and bicycles

(722).

• Public perception of risk is by far the greatest with air travel.

Space Shuttle Challenger

• January 28, 1986• The Challenger disintegrated 73 seconds into its flight after lift-off.• All 7 crew members were killed.

• The O-rings, as well as many other critical components, had no test data to support any expectation of a successful launch in such conditions.

• The lowest safe launch temperature was confirmed at 4o degrees F.• The morning of the launch was 18 degrees F.

Causes of Failure

• Insufficient knowledge ............................... 36% Underestimation of influence ......................... 16% Ignorence, carelessness, negligence .................. 14% Forgetfulness, error ................................. 13%

Relying upon others without sufficient control ....... 9% Objectively unknown situation ........................ 7% Unprecise definition of responsibilities ............. 1% Choice of bad quality ................................ 1%

Other ................................................ 3%Conducted by the Swiss Institute of Technology, Zurich

• http://www.matscieng.sunysb.edu/disaster/

AGENDA SEPT 27

• BIG QUESTION: How do research and brainstorming contribute to the overall success of your catapults?

• 1. Finish PRESENTATIONS!!!• 2. Discuss Alternate means of firing.• 3. Continue on Scale diagrams and materials.• 4. Check-In with each team – Ask questions, be ready to

show me your progress on your diagrams and specs.• 5. Homework: ENGI Disasters Topic due MONDAY

Alternate Means of Firing

• Look into different methods of launching your projectiles.

• If your first torsion design is unsuccessful, have a secondary means to create the force necessary to launch the golf ball.

• How might you be able to accomplish this?

The Mangonel Catapult

TENSION

• Develop some type of tension mechanism to accomplish this task.

• Consider a Crossbow and its basic functions.

• Keep in mind, you still need to work within your constraints when considering this second design.

• Design it using the same materials available to you.• You will be able to make changes as you build it.

(STEP 7)

Question of the Day

• What is the equation of the Pythagorean Theorem?

DO NOW

• Given a right triangle with side A equal to 12 inches in length and angle A equal to 60 degrees, find the length of side B.

Solving Right Triangles

• http://www.khanacademy.org/math/trigonometry/basic-trigonometry/basic_trig_ratios/v/example--trig-to-solve-the-sides-and-angles-of-a-right-triangle

Pythagorean Theorem

Sin (theta) = b / c Cos (theta) = a / c

DO NOW Feb 10

• http://science.howstuffworks.com/transport/29341-extreme-engineering-maglev-train-video.htm

• Watch the following video clip.

• After you have watched the clip, write some pros and cons of this new engineering marvel.

• Consider factors such as safety, cost, and public perception of risk.

• Write down your own opinion of this technology.

MHD Propulsion

• A method for propelling vessels using only electric and magnetic fields with no moving parts.

• Electrification of the propellant (gas or water) can then be directed by a magnetic field, pushing the vehicle in the opposite direction.

• http://www.youtube.com/watch?v=NEmgSpJK9qQ

Magnetohydropropulsion (MHD)

Top: US Navy Testing of Rail Gun Technology

Left: Yamato 1 Seacraft and MHD Drive Engine

Agenda Feb 10

• BIG Question: How do different bridge designs affect their ultimate yield strength?

• 1. DO NOW• 2. Bridge Design Challenge• All Teams Building Bridge Components• Remember your Constraints

• 3. Trimester Exam

Agenda Feb 11

• BIG Question: How do different bridge designs affect their ultimate yield strength?

• 1. DO NOW• 2. Bridge Design Challenge• All Teams Building Bridge Components• Remember your Constraints

• 3. BRIDGE TESTING on THURSDAY Feb 13• ALL TEAMS MUST BE READY!

Agenda Feb 14

• BIG Question: How do different bridge designs affect their ultimate yield strength?

• 1. DO NOW• 2. Bridge Design Challenge• All Teams Building Bridge Components• Remember your Constraints

• 3. BRIDGE TESTING TODAY!!!• ALL TEAMS MUST BE READY!

Agenda Feb 17

• BIG Question: How do different bridge designs affect their ultimate yield strength?

• 1. DO NOW• 2. Bridge Design Challenge• 3. BRIDGE TESTING TODAY!!!• ALL TEAMS MUST BE READY!

• HAND IN YOUR HOMEWORK – • Pink Handouts

Parts List

• Raw Materials and Fabricated Materials• Include everything you will need to assemble

your catapult.• Your materials will be ordered and specced based

upon this list. Be careful with measurements and triple check!!!

• This list must be typed – NO EXCEPTIONS

Parts List Requirements

• 1. Each Part required for your catapult design must be sketched out to scale (to fit on the paper).

• Each Part must include all specifications (length, width, etc).

• 2. Include a list of the total amount of hard parts you require for your project.

• This list will be used to order all of the parts for your catapult.

Parts List

• For example: • 2 pieces of 1” x 2” wood 36 inches in length• 2 (18 inch) 2” x 2” pieces of wood with 45

degree cuts at the two ends.

Question of the Day Feb 17

• The problem you are faced with solving is the launching of a projectile for maximum damage over a very short distance. You will be using a catapult to achieve this goal. The ideal angle of launch to achieve this is

• A. 45 degrees• B. 60 degrees• C. 30 degrees• D. 85 degrees

DO NOW

• Watch the following video clip.• Write down factors that engineers and architects must

be aware of and consider in the design and assembly process of a skyscraper.

• http://science.howstuffworks.com/483-how-the-worlds-tallest-building-works-video.htm

Agenda Feb 18

• BIG Question: How do different bridge designs affect their ultimate yield strength?

• 1. DO NOW• 2. Engineering Marvels

• World’s Tallest Buildings• HAND IN YOUR HOMEWORK – • Pink Handouts

Tallest Buildings

• Criteria introduced in 1996 to end the dispute between the Willis Tower and the Petronas Towers located in Chicago, Il.

• 1.Height to Architectural Top (including spires and pinnacles, but not antennas, masts or flagpoles). This measurement is the most widely used and is used to define the rankings of the 100 Tallest Buildings in the World.

• 2.Highest Occupied Floor• 3.Height to Top of Roof (omitted from criteria from

November 2009 onwards)

Tallest Buildings

• The Burj Khalifa 2722 ft or 829.8 m• Completed in 2010• Mixed Use

• One World Trade Center 1776 ft or 521 m• Office

• Princess Tower 1358 ft or 414 m• Residential

Tallest Buildings

Building the World’s Tallest Hotel

• http://www.youtube.com/watch?v=RGzSNZudEHw

• Complete the Megastructures Question Set as you watch the video.

Question of the Day

• Which step of EDP involves the incorporation of multiple ideas into a final design?• A. STEP 2• B. STEP 5• C. STEP 6• D. STEP 7

ANSWER

• Which step of EDP involves the incorporation of multiple ideas into a final design?

• A. STEP 2 (Constraints and Criteria)• B. STEP 5 (Explore Possibilities)• C. STEP 6 (SELECT AN APPROACH)• D. STEP 7 (Build a Model Prototype)

AGENDA OCT 12

• Big Question: How does engineering allow man to constantly build bigger and better structures?

• 1. Modern Marvels – Building a super structure.• Finish Video Clip/Question Set• Due upon completion of video

• 2. QUIZ on The Responsibilities of an Engineer• Public Perception of Risk

• 3. Engineering Disasters Critique• DUE FRIDAY OCT 18 (On webpage)• Requirements also posted• Be sure that your disaster meets all of the criteria for the

project before you start writing.

AGENDA OCT 11

• Big Question: How does engineering allow man to constantly build bigger and better structures?

• 1. Modern Marvels – Building a super structure.• Finish Video Clip/Question Set• Due upon completion of video

• 2. Media Center VHS Room• 3. Engineering Disasters Critique• DUE FRIDAY OCT 18 (On webpage)• Requirements also posted• Be sure that your disaster meets all of the criteria for the

project before you start writing.

AGENDA Mar 3

• BIG Question: How does EDP affect the success of your catapult/trebuchet?

• 1. All teams working on energy mechanisms.• Notify me of any materials you still require!!! • Bring in materials from home.

• 2. Project Testing to begin on Wednesday• 3. Final Reflection on Friday Mar 7• 4. Trimester 2 ends on Friday Mar 7