what does a machine change to make work easier? check all that apply.
Summary
Students continue to explore the story of building a pyramid, learning about the simple automobile called a pulley. They learn how a pulley tin can be used to change the direction of practical forces and move/lift extremely heavy objects, and the powerful mechanical advantages of using a multiple-pulley system. Students perform a simple demonstration to see the mechanical advantage of using a pulley, and they identify modern day technology applications of pulleys. In a easily-on activity, they meet how a pulley tin can change the management of a forcefulness, the difference between stock-still and movable pulleys, and the mechanical advantage gained with multiple / combined pulleys. They too learn the many means engineers utilize pulleys for everyday purposes.This engineering science curriculum aligns to Side by side Generation Science Standards (NGSS).
Engineering Connection
Engineers are experts at exploiting the advantages of simple machines in all sorts of real-world applications that benefit society. They incorporate the mechanical advantage of pulleys into their design of many modern-day structures, machines, products and tools, such as cranes, elevators, flagpoles, aught lines, motors, bicycle rings/bondage, clothes lines, h2o well bucket/rope, rock climbing devices, window blinds and sheet/fishing boats. Using multiple pulleys in conjunction with motors and electronics, engineers create complex modern devices that perform much work for very little power.
Learning Objectives
Afterward this lesson, students should be able to:
- Demonstrate how pulleys are used.
- Explain how pulleys could take been used by engineers in aboriginal times to practise piece of work.
- Identify modern applications in which engineers utilise pulleys.
Educational Standards Each TeachEngineering lesson or activeness is correlated to one or more than One thousand-12 science, technology, engineering or math (STEM) educational standards.
All 100,000+ K-12 Stem standards covered in TeachEngineering are collected, maintained and packaged by the Accomplishment Standards Network (ASN), a project of D2L (www.achievementstandards.org).
In the ASN, standards are hierarchically structured: first by source; east.g., by land; within source by type; east.g., science or mathematics; within type past subtype, then by grade, etc.
Each TeachEngineering lesson or activeness is correlated to one or more than One thousand-12 science, technology, engineering or math (STEM) educational standards.
All 100,000+ K-12 Stem standards covered in TeachEngineering are collected, maintained and packaged by the Accomplishment Standards Network (ASN), a project of D2L (www.achievementstandards.org).
In the ASN, standards are hierarchically structured: first by source; east.g., by land; within source by type; east.g., science or mathematics; within type past subtype, then by grade, etc.
NGSS: Adjacent Generation Science Standards - Science
| NGSS Performance Expectation | ||
|---|---|---|
| 3-PS2-1. Plan and carry an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object. (Grade 3) Do you agree with this alignment? Thanks for your feedback! | ||
| Click to view other curriculum aligned to this Performance Expectation | ||
| This lesson focuses on the post-obit Three Dimensional Learning aspects of NGSS: | ||
| Scientific discipline & Technology Practices | Disciplinary Cadre Ideas | Crosscutting Concepts |
| Plan and deport an investigation collaboratively to produce data to serve as the basis for evidence, using fair tests in which variables are controlled and the number of trials considered. Alignment agreement: Thank you for your feedback! Science investigations utilize a variety of methods, tools, and techniques.Alignment understanding: Thank you for your feedback! | Each strength acts on one particular object and has both strength and a direction. An object at residuum typically has multiple forces acting on it, but they add to give zero internet force on the object. Forces that practice not sum to zero can crusade changes in the object's speed or direction of motion. (Boundary: Qualitative and conceptual, but non quantitative add-on of forces are used at this level.) Alignment agreement: Cheers for your feedback! Objects in contact exert forces on each other.Alignment understanding: Thanks for your feedback! | Cause and outcome relationships are routinely identified. Alignment agreement: Thanks for your feedback! |
| NGSS Performance Expectation | ||
|---|---|---|
| 3-PS2-two. Make observations and/or measurements of an object's motion to provide show that a pattern can be used to predict future move. (Grade 3) Do yous agree with this alignment? Thanks for your feedback! | ||
| Click to view other curriculum aligned to this Performance Expectation | ||
| This lesson focuses on the post-obit Iii Dimensional Learning aspects of NGSS: | ||
| Science & Engineering science Practices | Disciplinary Cadre Ideas | Crosscutting Concepts |
| Make observations and/or measurements to produce data to serve equally the basis for bear witness for an explanation of a miracle or examination a design solution. Alignment agreement: Thanks for your feedback! Science findings are based on recognizing patterns.Alignment agreement: Cheers for your feedback! | The patterns of an object'southward motion in diverse situations can be observed and measured; when that past motion exhibits a regular pattern, future motion tin be predicted from it. (Boundary: Technical terms, such every bit magnitude, velocity, momentum, and vector quantity, are not introduced at this level, but the concept that some quantities demand both size and direction to be described is developed.) Alignment agreement: Thanks for your feedback! | Patterns of change tin be used to brand predictions. Alignment understanding: Thanks for your feedback! |
Mutual Core State Standards - Math
- Multiply and divide inside 100. (Course 3) More Details
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Exercise you concur with this alignment? Thank you for your feedback!
International Technology and Engineering Educators Association - Technology
- Demonstrate how tools and machines extend human capabilities, such as holding, lifting, carrying, fastening, separating, and calculating. (Grades 3 - 5) More Details
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Worksheets and Attachments
Visit [www.teachengineering.org/lessons/view/cub_simple_lesson05] to print or download.More than Curriculum Like This
Upper Elementary Activity 
Pulley'ing Your Own Weight
Using mutual materials (spools, string, soap), students learn how a pulley tin can exist used to easily modify the direction of a force, making the moving of large objects easier. They come across the divergence betwixt stock-still and movable pulleys, and the mechanical advantage gained with multiple/combined pulleys. ...
Middle School Lesson
Levers That Lift
Students are introduced to three of the six simple machines used past many engineers: lever, caster, and wheel-and-axle. In general, engineers use the lever to magnify the force practical to an object, the pulley to lift heavy loads over a vertical path, and the wheel-and-axle to magnify the torque appl...
Upper Elementary Lesson
Applied science: Simple Machines
Students are introduced to the six types of simple machines — the wedge, bike and beam, lever, inclined aeroplane, screw, and pulley — in the context of the construction of a pyramid, gaining high-level insights into tools that have been used since aboriginal times and are still in use today.
Upper Elementary Lesson
Permit'due south Move It!
Students explore methods employing simple machines probable used in ancient pyramid building, as well equally common modern-mean solar day cloth transportation. They learn nearly the wheel and axle as a means to ship materials from rock quarry to construction site.
Pre-Req Noesis
General cognition of pyramids. Familiarity with the six simple machines introduced in Lesson 1 of this unit of measurement.
Introduction/Motivation
We are well underway in learning about simple machines and building the ancient Egyptian pyramids that we have been hired equally engineers to pattern and construct. At present, nosotros are going to go deeper into our agreement of pulleys to see if we can utilise this knowledge to help make our work easier.
No one knows for sure if pulleys were ane of the simple machines that ancient cultures used to build pyramids. A few people believe that the beautiful and massive pyramids could not possibly take been built using something as simple as simple machines. Some people take wild theories about how the pyramids came to be — that perhaps aliens from another planet came to Earth and built them. Well, nosotros do not know about that, but nosotros do know that human being beings are very creative and resourceful when they desire to be. As long every bit nosotros limit ourselves to materials and technologies that would have been available to the ancient Egyptians, information technology is acceptable for us to use our knowledge to construct pulley systems to build our pyramid.
A pulley is a simple auto consisting of a string (or rope) wrapped around a wheel (sometimes with a groove) with one end of the cord attached to an object and the other stop attached to a person or a motor. Pulleys may seem uncomplicated, but they can provide a powerful mechanical advantage so lifting tasks may be done easily.
Pulleys are used in many ways, everyday. What kind of pulleys can yous recall of? Some mutual examples are large construction cranes that utilise pulleys to lift heavy objects with what would ordinarily be a very underpowered motor (encounter Figure 1), weight machines at a gym, some elevators, flagpoles, window blinds, bicycle rings/bondage, clotheslines, water well saucepan/rope, zip lines, motors, rock climbing devices, and sailing and fishing boats (see Figure two).
An lift is a modern engineering science apply of a pulley system that performs much like the raising of a large stone for pyramid building. Without the use of pulleys, an elevator would require a big motor to pull the cable straight upwards. Instead of using a large motor, some elevators use a big weight that takes advantage of gravity to aid enhance the lift car (see Figure 3). In this state of affairs, the powering motor can be much smaller and only be used to determine the direction the elevator should go.
But how can a bike with string over it help us move the huge stones required to build a pyramid? Well, pulleys help us by changing the direction of the force we use to lift an object. Is it easier for y'all to pull upwardly on a rope or pull down on a rope? By using a pulley, we do not have to pull up on a rope to elevator a heavy object attached to information technology, but instead we tin pull downwards on information technology. Call back of a flagpole as an example. When you pull down on the rope of a flagpole, the flag goes up the pole to wave in the air. That's considering a flagpole has a pulley on it. By using pulleys to redirect force, a stone could be lifted off the ground, allowing more than people to take hold of on to the rope, and adding weight so workers have to pull less. To simplify this endeavor fifty-fifty more than, workers using a caster could move a big stone up a ramp past pulling on a rope while walking down the ramp, using gravity to their reward.
The real mechanical advantage of a pulley is in using many pulleys at one time. Using multiple pulleys decreases the amount of force necessary to movement an object by increasing the corporeality of rope used to raise the object. The mechanical advantage (MA) of a caster system is equal to the number of ropes supporting the movable load. (That means, do not count ropes that are just used for redirecting, see Figures half dozen and vii.) Nosotros know from other lessons on simple machines that to proceeds a greater mechanical advantage, at that place is a merchandise-off. With a pulley, the trade-off is altitude. So, if two pulleys are used together, the corporeality of force required is cut in half, but twice the amount of rope is needed to be pulled to raise the object to the aforementioned desired height. (Illustrate this concept to students by conducting the following classroom demonstration; run across Figure 4.)
Classroom Broom and Rope Demonstration:
This demo requires three students, 2 brooms and ~6 meters of rope. Necktie the rope to one of the brooms (broom ane) and wrap the rope around the other broom (broom ii). Have two students stand about a meter apart each holding 1 broom, and effort to keep the brooms separated while the tertiary student pulls on the costless terminate of the rope; it should be a difficult task to pull the broom sticks together. Next, wrap the rope around each of the brooms again. Effort once more to pull the students/brooms together; the more times you wrap the rope around the brooms, the easier it is for the 3rd student to pull the others together! This is an example showing the power of mechanical advantage. Refer to the associated activity Pulley'ing Your Ain Weight to further students involvement in understanding pulley systems by illustrating how a pulley can be used to easily modify the direction of a force, making the moving of big objects easier.
Pulleys can be much more complicated. Engineers combine many pulleys into a pulley system that significantly reduces the corporeality of force required to lift an object. They often use caster systems to move extremely heavy objects. A cake and tackle is an case of a pulley system that can be attached to anything. It may take a lot of cable or rope, just a human using enough pulleys could lift several tons. Engineers use the cake and tackle along with motors and electronics to create modern devices that operate with very low power requirements, such as cranes and elevators. At Disneyland, engineers even use a pulley arrangement to motility Tinkerbell beyond the sky.
Nosotros are unsure if the Egyptians used pulleys, and have even so to find any testify that they did, only nosotros do know, that if they had used them, life would have been easier than if they did not. Now, since nosotros empathize pulleys and take modernistic materials, we tin can build the pyramids much easier. Today we are going to look at technology a caster system and run across if we tin design a way to get our heaviest stones to the top of our pyramid with the help of this simple machine.
Lesson Background and Concepts for Teachers
Use the Pulleys and the Pyramids PowerPoint presentation equally a helpful classroom tool. (Show the PowerPoint presentation, or print out the slides to employ with an overhead projector. The presentation is animated to promote an research-based way; each click reveals a new point about each machine; accept students advise characteristics and examples before you reveal them.)
The pulley, a uncomplicated machine, helps to perform work past changing the direction of forces and making easier the moving of large objects. When thinking of pulleys, most people call up of the blazon of pulley that allows a person to redirect the management of a force. With this type of pulley — called a fixed pulley — pulling down on a rope makes an object rise off the ground. At that place are besides movable pulleys and pulley systems. Thousands of years ago, early engineers used pulleys to help with construction and many useful everyday tasks. Many obelisks were erected using pulleys and wells have pulleys to help retrieve water.
Fixed Pulleys
The well-nigh ordinarily understood concept of a pulley is that information technology is a elementary machine that redirects force. This means that past looping rope effectually a pulley and attaching the rope to an object, one pulls down on the rope to raise the object, instead of having to lift the object (see Figure 5; imagine raising a flag). Although this is a helpful and user-friendly employ for pulleys, it has a major limitation: the force you must apply to lift the object is the same amount as if y'all were but lifting the object without the pulley (which is acceptable for raising a flag, but not helpful enough if trying to raise a pyramid rock). This means that a fixed caster does not give whatever mechanical reward.
A fixed caster configuration is useful for raising an object to a level to a higher place your head. Using this blazon of pulley besides enables yous to take advantage of gravity. And, by attaching weights to the finish of the rope that yous pull, you can lessen the corporeality of forcefulness y'all must apply. This blazon of pulley can also be used to rest an object, by attaching objects of equal weight to both sides of the rope, neither object moves. Once a force is practical to either side, the organisation continues moving in that direction. This kind of pulley system is used in some elevators. The elevator has cable attached to it that goes up, effectually a pulley, then comes downwardly and attaches to a counterweight. The motor that moves the elevator car uses much less power since the counterweight keeps the elevator balanced.
Movable Pulleys
Another type of caster is a movable pulley. In a movable pulley system, the rope is attached to a stock-still (non-moving) point, the pulley is fastened to the object that you want to motion and the other end of the rope is left free (run into Figure 6). By pulling on the rope, the caster moves and the object raises. This type of organization is skillful if you are trying to heighten an object located beneath you to your level. In a variation, if both sides of a movable pulley system are fixed and the rope is taut between the fixed points, the system becomes similar a wheel and beam because the object can ride forth the rope if a force is practical to it (for example, a zip line).
Pulley Systems
Using a system of pulleys can be much more complex and provide a powerful mechanical advantage — profoundly reducing the amount of strength required to motion an object. If one movable pulley is used (Figure vi), the amount of force required to raise the object attached to the movable pulley is cut in half. The pulley system seen in Figure 7 does non modify the mechanical advantage from Effigy 6, even so, it does change the direction of the necessary force. The trade-off is that the amount of rope required increases and the amount of rope that you must pull to raise the object is also increased. If 2 fixed pulleys are added to the system and a 2d movable pulley is attached to the object, the amount of forcefulness needed to raise the object becomes one-quaternary of the object's weight, and four times equally much rope is required (meet Figure 8 and Pulleys and the Pyramids PowerPoint presentation).
Mechanical Advantage
The powerful mechanical advantage of a pulley is in using many pulleys at one time. Combining multiple pulleys decreases the amount of force necessary to movement an object by increasing the corporeality of rope used to raise the object. The amount of rope tin can be establish by rope = original corporeality of rope x the number of pulleys. The mechanical reward (MA) of a pulley arrangement is equal to the number of ropes supporting the movable load. (That means, do not count ropes that are simply used for redirecting, run into Figures six, seven and 8.)
Associated Activities
- Pulley'ing Your Own Weight - Using mutual materials (spools, string, soap), students larn how a pulley can be used to hands change the management of a force, making the moving of large objects easier. They come across the difference between stock-still and movable pulleys, and the mechanical reward gained with multiple/combined pulleys. They too learn the many ways engineers employ pulleys for everyday purposes.
Scout this activity on YouTube
Lesson Closure
How can pulleys make our lives easier? Pulleys are powerful simple machines. They tin alter the direction of a force, which tin brand it much easier for us to motion something. If we want to lift an object that weighs ten kilograms i meter loftier, we tin can lift it direct upward or we can use a pulley, and so we tin can pull down on one end to lift the object upwardly. Information technology is much easier to use the pulley because, as long equally we weigh more than ten kilograms, we can just hang onto the stop of the rope and take advantage of gravity so our weight provides all the necessary force to lift the object.
Pulleys tin also provide us with a mechanical advantage when nosotros use several together and more rope. This procedure lessens the amount of forcefulness required to lift something.
While nosotros do not know if pulleys were used by ancient pyramid builders, we know pulleys are an ideal elementary automobile for many of the tasks required to build a pyramid. In today'due south highly-technical world, engineers still use pulleys to make difficult tasks easier. Without them, our lives would be much more hard.
Deport summary cess activities every bit described in the Assessment section. Conclude by finishing the KWL Chart and assigning Word Problems in which students calculate the mechanical reward of an inclined airplane (see the Assessment section).
In other lessons of this unit of measurement, students written report each simple machine in more item and run into how each could be used equally a tool to build a pyramid or a modern building.
Vocabulary/Definitions
fixed caster: A pulley system in which the caster is attached to a fixed point and the rope is attached to the object.
forcefulness: A push or a pull on an object; the capacity to do work.
gravity: The natural force of allure exerted by Earth upon objects at or almost its surface, tending to draw them toward the centre of the trunk.
mechanical advantage: An advantage gained by using simple machines to achieve work with less endeavour. Making the task easier (which means it requires less forcefulness), just may crave more fourth dimension or room to work (more distance, rope, etc.). For case, applying a smaller force over a longer altitude to achieve the same event as applying a big force over a modest distance. The ratio of the output force exerted by a machine to the input strength applied to it.
movable pulley: A caster organization in which the pulley is attached to the object; 1 end of the rope is attached to a fixed bespeak and the other end of the rope is free.
caster: A simple machine that changes the direction of a force, often to lift a load. Usually consists of a grooved wheel in which a pulled rope or concatenation runs.
redirect strength: To change the direction of your push or pull to gain advantage over a job.
simple automobile: A machine with few or no moving parts that is used to make piece of work easier (provides a mechanical advantage). For example, a wedge, cycle and beam, lever, inclined aeroplane, screw, or pulley.
work: Force on an object multiplied past the distance it moves. Due west = F x d (force multiplied by altitude).
Assessment
Pre-Lesson Assessment
Brainstorming: As a class, have the students engage in open discussion. Remind students that in brainstorming, no thought or suggestion is "silly." All ideas should be respectfully heard. Take an uncritical position, encourage wild ideas and discourage criticism of ideas. Accept them raise their easily to respond. Write their ideas on the board. Ask the students:
- What are uncomplicated machines? What is the reward of simple machines? (Possible answers: A machine with few or no moving parts that is used to make work easier. Simple machines make piece of work easier by creating a mechanical advantage, such as trading more distance for less force.)
- Why do engineers care most simple machines? (Answer: Modern equipment, structures and tools use the simple machine principles to perform unproblematic and complex tasks. Although yous may never encounter a pulley in action on the job site pulleys are subconscious inside motors, inside cranes, and are working behind the scenes all the fourth dimension.)
Know / Want to Know / Larn (KWL) Chart: Create a classroom KWL nautical chart to help organize learning virtually a new topic. On a large sheet of newspaper or on the classroom board, draw a chart with the championship "Simple Machines: Pulleys." Draw 3 columns titled, Chiliad, W and 50, representing what students know about pulleys, what they want to know near pulleys and what they learned nigh pulleys and their mechanical advantages. Make full out the K and W sections during the lesson introduction as facts and questions emerge. Fill up out the L section at the end of the lesson.
Postal service-Introduction Cess
Discussion Questions: Solicit, integrate and summarize educatee responses.
- What did nosotros find during the broom and rope demo? What was the result of adding more pulleys? (Possible answers: Pulleys in action, using mechanical advantage to make piece of work easier, adding more than pulleys (wraps of rope) made pulling the two brooms together easier.)
- Explain how to notice the mechanical advantage of a pulley system. (Reply: The mechanical advantage of a pulley is system is equal to the number of ropes supporting a movable pulley.)
- What is the trade-off of mechanical advantage in a pulley system? (Answer: Distance or length of rope.)
- What are some examples of modernistic items that engineers accept designed with pulleys? (Possible answers: Cranes, elevators, cake and tackle on boats, flagpoles, zip lines, motors, cycle rings/chains, stone climbing devices, window blinds and sail boats.)
Lesson Summary Cess
KWL Chart (Conclusion): Equally a class, finish column L of the KWL Chart equally described in the Pre-Lesson Assessment section. List all of the things students learned nearly pulleys and their mechanical advantages. Were all of the W questions answered? What new things did they learn? Based off of their observations of an object's motion can a pattern be used to predict future movement?
Word Issues: Assess students' understanding of the lesson concepts by assigning the following word problems. Write on the board: Mechanical advantage of a caster organization = number of number of rope segments supporting the load.
- If we used i fixed caster and wanted to raise a rock 100 meters, how much force and rope would it have to raise a 500-kilogram rock? (Answer: Force is equal to the weight of the rock, and so 500 kilograms. Since nosotros are using only one pulley, the rope would need to exist at least 100 meters long [the altitude from the caster to the rock], just would more likely be around 200 meters [i length up to the caster from the stone and one length from the pulley to you].)
- If we used 10 pulleys in a system and wanted to raise a stone 100 meters, how much forcefulness and rope would nosotros demand to raise that aforementioned 500-kilogram rock? (Answer: The force could be lowered to ane/10th the weight of the rock [50 kilograms] since we would have ten ropes with the pulleys. However, we would easily need 1,000 meters of rope [x times the length of one rope] or 2,000 meters if we were at the aforementioned level as the stone.)
Lesson Extension Activities
Endeavour making a human pulley. You need lath, a strong rope and a spot with an overhead support, such as a soccer goal or playground equipment. Wrap i end of the rope effectually a ii 10 four (or something strong such as a seat from a swing) and wrap the other cease of the rope around the goal, letting the trailing end hang to the footing. Allow ane kid to sit on the ii 10 iv while two other children try to elevator them by pulling down on the costless cease of the rope. Keep wrapping the rope around the goal or back up bar until 2 children tin can easily lift the sitting child up and downwards. It may be helpful to start the sitting kid from a standing position (both anxiety on the ground).
If the students are unfamiliar with a nix line, have them research this on the net. A nada line is a fun case of a movable pulley.
Challenge more avant-garde students to calculate the mechanical reward of using multiple pulleys, requiring sectionalization with remainders or fractions.
References
Dictionary.com. Lexico Publishing Grouping, LLC. Accessed January 25, 2006. (Source of some vocabulary definitions, with some accommodation) http://www.dictionary.com
Copyright
© 2005 past Regents of the Academy of Colorado.Contributors
Justin Fritts; Lawrence E. Carlson; Jacquelyn Sullivan; Malinda Schaefer Zarske; Denise Carlson, with design input from the students in the spring 2005 Thousand-12 Engineering science Outreach Corps course.Supporting Program
Integrated Teaching and Learning Plan, College of Engineering, Academy of Colorado BedrockAcknowledgements
The contents of these digital library curricula were developed by the Integrated Education and Learning Program under National Science Foundation GK-12 grant no. 0338326. However, these contents exercise not necessarily stand for the policies of the National Science Foundation, and you should not presume endorsement by the federal government.
Final modified: April vii, 2022
Source: https://www.teachengineering.org/lessons/view/cub_simple_lesson05
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