PulleysSimple Machines

A STEM-Maker Level 1 Lesson for System Fluency

Education Standards

Curriculum

Turn Any Space Into a STEM Lab

Standards for Technological Literacy

2.K-2 2.3-5 2.6-8 2.9-12 8.K-2 8.3-5 8.6-8 8.9-12 9.K-2 9.3-5 9.6-8 9.9-1210.K-2 10.3-5 10.6-8 10.9-12

Next Generation Science Standards

3-5-ETS1-1 MS-ETS1-1 HS-ETS1-13-5-ETS1-2 MS-ETS1-2 HS-ETS1-23-5-ETS1-3 MS-ETS1-3 HS-ETS1-3 MS-ETS1-4 HS-ETS1-4

Common Core Standards

W.5.7 RST.6-8.1 WHST.6-8.9W.5.9 RST.6-8.7 RST.11-12.7MP.2 RST.11-12.8 RST.11-12.9 MP.4 MP.5 SL.8.5

STEM-Maker

Educational ObjectivesAfter this lesson, students should be able to understand and apply the following concepts:

Basic elements of a pulley

Transfer of motion from one directionto another

Calculate mechanical advantage

Construct a model of a pulley crane

Conduct an authentic assessment of mathematical predictions and calculations

Intrinsic value of pulleys and the ability to transfer that knowledge to future applications and solutions

Table of Contents

Introduction Introduction ............................................................................................................................ 1 Key Terms .............................................................................................................................. 1 Additional Resources .............................................................................................................. 1 Building Basics with Rokenbok ................................................................................................ 2

Technology and Engineering Bill of Materials ...................................................................................................................... 3 Building a Pulley Crane ........................................................................................................... 3-4

Science Concepts What is a Pulley? ..................................................................................................................... 5 Types of Pulleys ...................................................................................................................... 5

Math Concepts Calculating Mechanical Advantage ........................................................................................... 6

STEM Challenges Building with Pulleys ................................................................................................................ 7

Assessment What Have We Learned? ......................................................................................................... 8

Level 1 Simple Machines: The Pulley

WelcomeFrom basic STEM literacies to 3D solid modeling, Rokenbok STEM-MAKER curriculum was created to help you teach technology, engineering, and design in almost any setting. Rokenbok’s STEM-Maker Curriculum guides fun and engaging hands-on project based challenges, and models the progression of fluencies mastered by real designers and engineers. Lesson plans are categorized in three progressive levels for grades 3-12 and align with NGSS and common core state standards. Progression through these levels builds confidence, a sense of accomplishment setting the groundwork for a love of learning, creating and making.

Step-by-step, single-solution projects introduce Rokenbok

materials and how thesystem works.

System Fluency Creative Fluency Engineering FluencyRealistic design briefs

challenge the student tosolve a problem basedon the

skills learned in Level 1. Students add their own design creativity to solve a problem using the

Rokenbok system.

A more advanced design brief challenges students to design

and build custom parts to complete a project. Students

use the Rokenbok Open Source Library and 3D solid modeling software to adapt and create their own parts

and tools.

IntroductionIntroductionThis Level 1 project is designed to introduce your students to one of the six simple machines, the pulley. Students will learn how pulleys work by making their own pulley system, applying the mathematics behind a pulley, as well as learning key terms related to the subject matter.

Key TermsPulley: A wheel and axle used in conjunction with a rope or cable that can use mechanical advantage to move heavy loads with minimal effort.

Simple Machine: A device that transmits or modifies force or motion.

Effort: Force used to move an object over a distance.

Resistance/Mass: Force to overcome in order for an object to be moved, otherwise known as load.

Block and Tackle: A system of two or more pulleys with a rope or pulley threaded between them, usually used to lift or pull heavy loads.

Mechanical Advantage: T he advantage gained by the use of a mechanism in transmitting force.

Additional Resourceshttp://scienceforkids.kidipede.com/physics/machines/pulley.htmhttp://www.youtube.com/watch?v=9T7tGosXM58http://teacher.scholastic.com/dirtrep/simple/pulley.htm

1

2

Building Basics with RokenbokYou will be using the Rokenbok Education ROK Ed Rover or SnapStack module forthis project.

Snapping:Rokenbok building components snap together for a snug fit. It is easier to snap pieces together by angling the beam into the block.

Bracing:Use braces to strengthen any Rokenbok build.Girders, 2-way braces, 3-way braces, andcorbels are all commonly used for this purpose.

Disassemble:Always use the Rokenbok key tool when taking apart pieces. Insert the tab on the key into the engineered slot on each piece and twist slightly. This will protect your fingers and minimize broken pieces.

Take Inventory:It is recommended to take inventory of all components at the end of each build anda complete check at the end of the school year. Replacement pieces can be foundonline at Rokenbok.com/Education

Component Care:All building components should be cleaned regularly with a mild detergent and water.

Snapping

Bracing

Disassemble

3

Technology & EngineeringBuilding a Pulley CraneFollow the step-by-step instructions to build a pulley crane.

2

Bill of Materials

10x 3x

9x

5x

Makes one pulley crane.

5x

2x

1 Building the Base

6x

Building the Beam Assembly

3 Building the Lever Assembly

4

5

Build Vertical Beam Assembly

Build Horizontal Beam Assembly

Technology & Engineering

4

Science ConceptsWhat is a Pulley?The pulley is a simple machine that consists of a wheel and axle system that uses a cable, rope or string in order to help lift heavy objects more easily.

Types of PulleysAdditional pulleys can be added to increase the mechancial advantage and make it easier to lift or pull heavy objects, but more rope or string is required to lift them. There are three main types of pulley systems: fixed, moveable and compound. A fixed pulley’s wheel and axle stay in one place. A fixed pulley does not give you any mechanical advantage, however, it does change the direction of the force. In example 1, the input force is pulling down which in turn, moves the load up. A moveable pulley is a pulley that is free to move up and down with the load. It provides mechanical advantage as less effort is required to move your load. In example 2, the input force needed to lift the load is less but notice that more rope is needed in order to lift the load. The third type of pulley is the compound pulley, which consists of combinations of fixed and movable pulleys.

5

Load(resistance/mass)Effort

Single Fixed Pulley

Fixed Pulley

1 Single Fixed/Single Moveable Pulley

Effort

Load(resistance/mass)

Fixed Pulley

Moveable Pulley

Double Fixed/Single Moveable Pulley

Effort

Load(resistance/mass)

Moveable Pulley

Fixed Pulley

Fixed Pulley

32

Math ConceptsCalculating Mechanical AdvantageMechanical advantage with a pulley is achieved by adding additional pulleys that disperse the load over several segments of the rope, thus allowing heavy loads to be lifted with minimal effort.If you tried to lift a 75 pound rock with just your muscles, you would have to be pretty strong to lift it, but by using a pulley system to lift the rock, we find that it is quite easy to do because of the mechanical advantage of the pulley system. Use the math formulas below to figure mechnical advantage of a pulley system.

6

Load(resistance/mass)

10 Pounds

10 Feet10 Feet

Effort10 Pounds

10 Feet

20 Feet

Effort5 Pounds Load

(resistance/mass)10 Pounds

Single Fixed Pulley Single Fixed/Single Moveable Pulley

MA = Load= 10Effort = 10

= 1 MA = Load= 10Effort = 5

= 2

To raise a 10 pound weight 10 feet high would require an effort of 10 pounds and you would have to pull the rope 10 feet in order to raise it 10 feet.

Therefore, no mechanical advantage is realized.

By adding a movable pulley we can achieve mechanical advantage because the load is carried by two sections of rope and the effort is less, but you would have to pull the rope twice as far.

STEM ChallengesWhat Can You Design?These STEM Design and Engineering Challenges are designed to introduce you to the pulley and how it can be used to make work easier for many different tasks. Try out one of the STEM Design and Engineering Challenges below or design your own project using the pulley.

Building with PulleysYou can use your pulley crane to lift various objects. Snap on some wheels to make it mobile, or redesign it so that it will rotate on the base.

Another option might be for you to build a tall crane or elevator system that would be able to lift objects up to different levels.

Use the science concepts and math formulas for determining the mechanical advantage of your finished project to see how this unique simple machine is used to solve very complex problems.

Other Uses for the PulleyThe pulley is a very useful simple machine. Not only can the mechanical advantage of a pulley be useful in lifting heavy loads, it can also be used in many other ways. Some of these include:

Transfer of motion from one direction to another direction

Ski lifts and gondolas

Tow trucks and come-a-longs

7

Pulley

AssessmentWhat Have We Learned?1. What are the two necessary parts for a pulley system? a. base and axle b. lever arm and fulcrum c. wheel/axle and rope or cable d. weight and effort

2. What type of pulley system is shown in this example? a. single fixed pulley b. double fixed pulley c. single fixed / double moveable pulley d. single fixed / single moveable pulley

3. Use the information below to determine the mechanical advantage of the pulley.

a. MA = 2 b. MA = 3 c. MA = 4 d. MA = 16

4. Force to overcome an object to be moved, otherwise known as load, is the definition for _____? a. effort b. leverage c. motion d. resistance

5. Which of the following examples would most likely use a pulley system? a. hammer b. block and tackle c. screwdriver d. file

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5 Feet

20 Feet

Effort2 Pounds

Load(resistance/mass)

8 Pounds

MA = ______

MA = Load = ?Effort = ?

= ?

50-00976-005

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