Simple Machines STEM

STEM-Maker
Curriculum
Turn Any Space Into a STEM Lab
Pulleys
Simple Machines
A STEM-Maker Level 1 Lesson for System Fluency
Educational Objectives
After this lesson, students should be able to understand and apply the
following concepts:
Basic elements of a pulley
Transfer of motion from one direction
to 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
Education Standards
Next Generation Science Standards
Common Core Standards
Standards for Technological Literacy
3-5-ETS1-1
3-5-ETS1-2
3-5-ETS1-3
W.5.7
W.5.9
MP.2
MP.4
2.K-2
8.K-2
9.K-2
10.K-2
MS-ETS1-1
MS-ETS1-2
MS-ETS1-3
MS-ETS1-4
HS-ETS1-1
HS-ETS1-2
HS-ETS1-3
HS-ETS1-4
RST.6-8.1
RST.6-8.7
RST.11-12.8
MP.5
WHST.6-8.9
RST.11-12.7
RST.11-12.9
SL.8.5
2.3-5
8.3-5
9.3-5
10.3-5
2.6-8
8.6-8
9.6-8
10.6-8
2.9-12
8.9-12
9.9-12
10.9-12
Welcome
From 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 STEMMaker 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.
System Fluency
Creative Fluency
Engineering Fluency
Step-by-step, single-solution
projects introduce Rokenbok
materials and how the
system works.
Realistic design briefs
challenge the student to
solve 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.
Table of Contents
Level 1 Simple Machines: The Pulley
Introduction
Introduction ............................................................................................................................
Key Terms ..............................................................................................................................
Additional Resources ..............................................................................................................
Building Basics ......................................................................................................................
Technology and Engineering
Building a Pulley Crane ...........................................................................................................
Science Concepts
What is a Pulley? .....................................................................................................................
Types of Pulleys ......................................................................................................................
Math Concepts
Calculating Mechanical Advantage ...........................................................................................
STEM Challenges
Building with Pulleys ................................................................................................................
Assessment
What Have We Learned? .........................................................................................................
1
1
1
2
3-4
5
5
6
7
8
Introduction
Introduction
This 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 Terms
Pulley:
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, also
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 Resources
http://scienceforkids.kidipede.com/physics/machines/pulley.htm
http://www.youtube.com/watch?v=9T7tGosXM58
http://teacher.scholastic.com/dirtrep/simple/pulley.htm
1
Building Basics with Rokenbok
You 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.
Snapping
Bracing:
Use braces to strengthen any Rokenbok build.
Girders, 2-way braces, 3-way braces, and
corbels are all commonly used for this purpose.
Bracing
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.
Disassemble
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 detergent and water.
2
Technology & Engineering
Building a Pulley Crane
Follow the step-by-step instructions to build a pulley crane.
Bill of Materials
Makes one pulley system.
3x
10x
2x
9x
1
Build the Base
2
Build the Beam Assembly
5x
5x
6x
3
Technology & Engineering
3
Build the Lever Assembly
4
Build Vertical Beam Assembly
5
Build Horizontal
Beam Assembly
4
Science Concepts
What 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 Pulleys
Additional 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.
Fixed Pulley
Fixed Pulley
Fixed Pulley
Effort
Effort
1
Load
Effort
Load
(resistance/mass)
Single Fixed Pulley
Fixed Pulley
Moveable
Pulley
Load
(resistance/mass)
2
Single Fixed/Single
Moveable Pulley
Moveable
Pulley
(resistance/mass)
3
Double Fixed/Single
Moveable Pulley
5
Math Concepts
Calculating Mechanical Advantage
Mechanical 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. 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.
Single Fixed Pulley
MA =
Load= 10 = 1
Effort = 10
Single Fixed/Single Moveable Pulley
MA =
Load= 10 = 2
Effort = 5
20 Feet
10 Feet
10 Feet
Load
Effort
10 Pounds
(resistance/mass)
10 Pounds
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.
10 Feet
Effort
5 Pounds
Load
(resistance/mass)
10 Pounds
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.
Therefore, no mechanical advantage is
realized.
6
STEM Challenges
What Can You Design?
These STEM Design and Engineering Challenges introduce you to the pulley and how it can be
used to make work easier for many different tasks. Try one of the STEM Design and Engineering
Challenges below or design your own project using the pulley.
Building with Pulleys
You 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 Pulley
The pulley is a very useful simple machine. Not only can the mechanical
advantage of a pulley help lift 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
Pulley
7
Assessment
What 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.
MA =
Load = ?
Effort = ?
=?
20 Feet
MA = ______
a.
b.
c.
d.
MA = 2
MA = 3
MA = 4
MA = 16
Effort
2 Pounds
5 Feet
Load
(resistance/mass)
8 Pounds
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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