ScrewSimple Machines

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

Basic elements of a screw

Relationship between pitch, slope, and threads per inch

Calculate mechanical advantage

Construct a model screw

Conduct an authentic assessment of mathematical predictions and calculations

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

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

A STEM-Maker Level 1 Lesson for System Fluency

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 Screw ..................................................................................................................... 3-4

Science Concepts What is a Screw? ..................................................................................................................... 5 Screw Examples ...................................................................................................................... 5

Math Concepts Calculating Attributes of the Screw ........................................................................................... 6

STEM Challenges Building a Propeller .................................................................................................................. 7

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

Level 1 Simple Machines: The Screw

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 based on 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 3D Virtual Parts Library and 3D solid modeling software to adapt and create

their own partsand tools.

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

Key TermsScrew: Threads, or inclined plane wrapped around a center shaft.

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

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

Threads: The sloped incline plane on a screw.

Slope: The distance for one complete rotation around the center shaft of the screw.

Pitch/Lead: Height of the inclined plane or distance between threads.

Online Key Search Termssimple machines mechanical advantage screwbolts/nuts screw jack threadscoarse/fine threads mechanical fasteners wine press

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2

Building Basics with RokenbokYou will be using the Rokenbok Education ROK Ed Rover or SnapStack Module for this 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, and corbels 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 and a complete check at the end of the school year. Replacement pieces can be found online at rokenbok.com/education.

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

Snapping

Bracing

Disassemble

Technology & EngineeringBuilding a Screw AssemblyFollow the step-by-step instructions to build a screw assembly.

2 Build the Thread of the Assembly

1 Build the Shaft Assembly

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Bill of Materials

9x 6x

3x 1x

4x

Makes one screw assembly.

3 Final Screw Assembly

Technology & EngineeringBuilding a Screw AssemblyFollow the step-by-step instructions to build a screw assembly.

4

3 Build the Thread of the Assembly

Drill Bits

Screws

Cork Screw

Bench Vise

Nuts

Science ConceptsWhat is a Screw?The screw is a simple machine that can be used to turn rotary motion (round and round) into linear motion (up and down). It is also used to interlock materials by twisting the threads of the screw into the material.

The power of the screw is determined by how close the threads are together. The closer the threads are together, the easier it is to twist into the material, but will take more twists to complete the job. Threads that are farther apart are harder to twist, but do not require as many twists.

As the screw is turned into materials such as wood, the angle of the threads pulls the screw into the wood and the friction between the threads and the material make it difficult to back out of the wood. This makes an excellent mechanical fastener to connect materials.

Screw ExamplesHere are a few of the examples of how the screw is used in common applications:

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Bolts

Rotary

Linear

Threads

LinearInto

Material

Math ConceptsCalculating Attributes of the ScrewThe benefit of the screw is based on a scientific concept called, mechanical advantage. By using a simple machine, we can make hard work easier, making it possible to build things that we don’t have the power to do with just our hands and muscles. While the screw is a simple concept, the inclined threads have tremendous power to lift heavy objects and fasten things together.

Use the formulas below to determine the mechanical advantage of a screw.

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Formula: PitchThe pitch of the screw is the distance between the threads and is determined by measuring the number of threads per inch.

Formula: CircumferenceThe distance around the outside edge of the screw is called circumference. To determine the circumference of a screw we use the following math formula: c = pd

The term pi p is a mathematical constant that represents the ratio of a circle’s circumference to its diameter which is approximately 3.14.

To figure the circumference of our screw, we use the following formula: c = 3.14 (p) x .25 (diameter) which means that the circumference of our screw is 0.785 inches.

Formula: Mechanical AdvantageWe can use mathematical formulas and measurements to help determine the mechanical advantage of a machine, including the screw. To determine the mechanical advantage of this screw, divide the circumference of the screw by the pitch of the screw.

Use the formula and given measurements shown to find the mechanical advantage of this screw.

Circumference (0.785)/Pitch = 1/8 (.125) = MA (6.28)

Circumferencec = pd

c(0.785) = 3.14 X .25

Pitch = number of threadsper inch/cm

1 = 1 8

8 Threads per inch

14

“

Diameter

Slope

Other Uses for the ScrewThe screw is a very useful simple machine. Not only can the mechanical advantage of a screw be useful in moving heavy loads and fastening materials, it can also be used in many other ways. Some of these include:

Transfer of motion from rotary motion to vertical linear motion

Wine press, augers and mechanical feed systems

Combines, post hole diggers, and turbines

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

Building a PropellerThis STEM Challenge is designed to use the screw assembly that you have built and turn it into a useful tool.

One application of the screw is included in the design of a propeller. Some propellers are used to move boats through the water and others are used to propel airplanes through the air.

Use additional Rokenbok building components to build a propeller that will rotate.

Now that you know how a propeller is made, you can apply this concept to build a model of a helicopter or whirligig.

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Combine

AssessmentWhat Have We Learned?1. The screw uses ______________ motion to transfer to linear motion. a. rotary b. intermittent c. fluid d. gravity

2. The screw is really a(n) __________________ wrapped around a center shaft. a. wheel and axle b. pulley c. inclined plane d. lever

3. Use the information below to determine the mechanical advantage of the screw. a. MA = 6.28 b. MA = 3.14 c. MA = 1.57 d. MA = 4.71

4. Which of the following examples is not a screw? a. combine header b. bolt c. nail d. propeller

5. The slope of a screw is determined by the __________________ a. distance between threads b. distance for one complete rotation around the screw c. number of threads on the screw d. number of threads per inch

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Mechanical Advantage of a ScrewCircumference/Pitch = MA

MA = ________

4 Threads per inch

18

“

Diameter

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