LeversSimple Machines

A STEM-Maker Level 1 for System Fluency

Education Standards

STEM-MakerCurriculum

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

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

Basic elements of a lever

Differentiate between first, second, and third class levers

Calculate mechanical advantage

Construct a model first class lever

Conduct an authentic assessment of mathematical predictions and calculations

Intrinsic value of levers and theability to transfer that knowledgeto 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 Lever ..................................................................................................................... 3-4

Science Concepts What is a Lever? ...................................................................................................................... 5 Classes of Levers .................................................................................................................... 5

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

STEM Challenges Building a Balance Beam Scale .. .............................................................................................. 7 Building a Scissor Arm ............................................................................................................. 7

Assessment

Level 1 Simple Machines: The Lever

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. Rokenboks 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 lever. Students will learn how levers work by making their own lever system, applying the mathematics behind a lever, as well as learning key terms related to the subject matter.

Key TermsLever: A rigid bar resting on a pivot, used to help move a heavy or firmly fixed load with one end when pressure is applied to the other.

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, object to be moved, otherwise known as load.

Fulcrum: The pivot point of a lever that helps create mechanical advantage.

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

Additional Resourceshttp://scienceforkids.kidipede.com/physics/machines/lever.htmwww.enchantedlearning.com/physics/machines/Levers.shtmlhttp://iqa.evergreenps.org/science/phy_science/ma.html

1

2Building 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

3Technology & EngineeringBuilding a LeverFollow the step-by-step instructions to build a lever.

2

Bill of Materials

9x 2x

4x

4x

Makes one lever.

4x

4x

1 Building the Base

8x

Building the Fulcrum

Technology & EngineeringBuilding a LeverFollow the step-by-step instructions to build a first class lever.

3

4

Building Lever Beam

Final Lever Assembly

4

Science ConceptsWhat is a Lever?Sometimes we need to lift a heavy object that is too much to do with muscles alone. The mass of the object and the gravitational force on the object must be overcome in order to lift the object.

The lever is a simple machine that is capable of lifting heavy loads by using mechanical advantage. Mechanical advantage is achieved by placing a fulcrum (pivot point) at a location on the lever arm that requires less effort to lift the object than by just using your muscles alone.

Classes of LeversThere are three classes of levers. First and second class levers provide mechanical advantage based on the location of the load, he fulcrum, and the effort, while a third class lever provides additional force and momentum.

Load(resistance/

mass)

Gravity (resistance)

Lever Arm

Lift

Fulcrum

Effort

EffortLever Arm

Fulcrum

Load(resistance/

mass)

First Class Lever

Fulcrum

Load(resistance/mass)

Effort

Load(resistance/mass)

Fulcrum

Effort

Second Class Lever

Fulcrum

Load(resistance/mass)

Effort

Third Class Lever

Fulcrum

Load(resistance/mass)

Effort

Load(resistance/mass)

Fulcrum

Effort

Load(resistance/mass)

Fulcrum

Effort

5

Math ConceptsCalculating Mechanical AdvantageMechanical Advantage with a lever is achieved by the positioning of the fulcrum point relative to each side of the lever. To determine the mechanical advantage for each type of lever, use the math formulas shown below:

First Class Lever

Fulcrum

Load(resistance/mass)

Effort

Load(resistance/mass)

Fulcrum

Effort

Second Class Lever

Fulcrum

Load(resistance/mass)

Effort

Third Class Lever

Fulcrum

Load(resistance/mass)

Effort

Load(resistance/mass)

Fulcrum

Effort

Load(resistance/mass)

Fulcrum

Effort

5 Feet(output)

25 Feet(input)

MA = Input Distance = 25 Output Distance = 5

= 5

With a mechanical advantage of 5, you could lift 5 times your mass by sitting on the 25 foot long side.

If you weighed 125 pounds and sat on the long side of the fulcrum, how much weight could you lift?

MA = Input Distance = 3 Output Distance = 1

= 3

3 Feet(input)

1 Foot(output)

By pushing up from the input end of the lever with a forceof 50 lbs., you can lift 150 lbs. of load with a mechanical advantage of 3.

If you pushed up the input end of the lever with a force of 20 lbs., how much could you lift with MA = 3?

125 (input) X 5 (MA) = _____ 20 (input) X 3 (MA) = _____

Only first class and secondclass levers can be used to create mechanical advantage.

The third class lever is used to create additional momentum because the load end is a long ways from the fulcrum point.

6

STEM ChallengesWhat Can You Design?These STEM Design and Engineering Challenges are designed to introduce you to the lever 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 lever.

Building a Balance Beam ScaleYou can use your first class lever to create a balance scale or move the fulcrum point to test the math concepts presented in the Math segment.

Other Uses for the LeverThe lever is a very useful simple machine. Not only can the mechanical advantage of a lever 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

Prying actions that allow for lifting or moving an object

Linkage from one simple machine to another

7

Building a Scissor ArmUse your knowledge of the lever to design and build a scissor arm that will reach out three feet.Use other components available to enhance your projects capabilities.

Lever

What Have We Learned?1. What are the two parts of a lever? a. load and effort b. lever arm and fulcrum c. base and axle d. fulcrum and load

2. The wheelbarrow is a good example of which type of lever? a. first class lever b. second class lever c. third class lever d. mobile lever

3. Use the information below to determine the mechanical advantage of the lever. a. MA = 2 b. MA = 3 c. MA = 4 d. MA = 16

4. Which type of lever does not use mechanical advantage, but creates additional momentum? a. first class lever b. second class lever c. third class lever d. motion lever

5. Prying a nail from a board using a claw hammer would be an example of what type of lever? a. first class lever b. second class lever c. third class lever d. claw lever

Assessment

MA = Input Distance = ? Output Distance = ?

= ?

Fulcrum

Load(resistance/mass)

Effort

2 Feet(output)

8 Feet(input)

MA = ______

Load(resistance/mass)

Fulcrum

Effort

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