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MSP:MiddleSchoolPortal/Get Moving With Simple Machines

From Middle School Portal


Get Moving With Simple Machines - Introduction

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Middle school teachers can meet many science content standards and build on their students’ elementary knowledge of simple machines by studying these machines in terms of Newton’s laws of motion. In elementary school, students usually learn the different types of simple machines and may understand that simple machines make work easier.

Your students may already be aware of these ways that work is made easier: Pushing a heavy load on wheels is easier then pushing it across the floor without wheels. Raising a heavy load is easier with a pulley than trying to lift it with human muscle only. Walking up a ramp requires less effort than trying to jump straight up to the same height. Catapulting an object sends it further and faster than a human being can throw it.

Simple machines make work (work = force x distance, W = fd) easier by decreasing the effort (EF) needed to lift a resisting load (RF), but simple machines simultaneously increase the distance over which that effort (ED) must be applied to move the load (RD):

EF x ED = RF x RD, where EF < RF and ED > RD

(This is an idealized equation. In reality, some force is transferred to the pivot point via kinetic energy, where it is converted to heat energy and dissipated to the environment.)

Contents

In middle school classes, Newton’s laws of motion are presented as three distinct concepts, but of course, all three are in action any time an object experiences a force that may or may not be enough to send it into motion. For example, when a skateboard rider applies a force to the ground with one foot to overcome the skateboard’s inertia and to accelerate the skateboard (1st law), the ground pushes back (3rd law), and the skateboard and rider accelerate in the direction of the ground’s applied force at a rate inversely proportional to the mass of the earth (2nd law). The skateboard is doing the work of a simple machine in that it is experiencing force over a distance, W = fd. Any object we use for work or pleasure can be described in terms of the work it accomplishes.

So the skateboard is capable of doing work. That implies it is a simple machine. Which one? Or might it be a compound machine, a combination of two or more simple machines in which force is transferred between the various simple machines involved? The answer is that it is a compound simple machine: a lever combined with wheels and axles.

What if your skateboard had only two wheels, not four? What if it could go uphill without one foot pushing off the street? Then you wouldn’t have a skateboard, you’d have a wave board! And you’d be "street surfing," not skateboarding. So why not call it a "street surf board?" After all, there are no waves in the street. Or are there? The wave board requires the rider to generate mechanical wave motion in order to roll. Can your students relate its technology to the science of simple machines?

Humans have been making and using simple machines for work and pleasure throughout history. We cannot imagine life without them. But who were the first clever technologists? What is the science behind their technology? What science do modern technologists use when designing and constructing simple machines today? What science will your students use when inventing their own technological innovations?

The study of simple machines is especially attractive for autumn, when students are just returning to school, perhaps reluctantly, and have a new group to get acquainted with. The mild weather means learners can get outside to conduct some of these activities, putting a positive spin on school and science. Many activities require teamwork, conducive to relationship building, enhancing your class’s sense of community.

This publication highlights a breadth of resources, lessons and activities you can use to address the standards appropriate to your teaching content through simple machines.

Background Information for Teachers

You will find resources here designed to help you with both content and pedagogy as you think about your unit on simple machines, forces, and motion. First, we direct you to some concept maps from the NSDL Strand Map Service. These maps illustrate connections between concepts and across grade levels. Because mathematics express force and motion scientific theories, an image of the middle grades (6-8) only part of the Ratios and Proportionality map appears below. This is one of ten maps under The Mathematical World. Many teachers have their students build a device incorporating simple machines, where consideration of forces on materials is integral. So we also included an image of the grades 6-8 portion of the Manufacturing map, under the Designed World heading. Clicking on a concept within the maps will show NSDL resources relevant to the concept, as well as information about related AAAS Project 2061 Benchmarks and National Science Education Standards. Move the pink box in the lower right hand corner of the page to see the grades 6-8 learning goals.

Ratios and Proportionality

View individual map Printable view of map

Resistance Is Futile This activity provides information on statics and dynamics with an emphasis on friction as an opposing force.

Review of Middle School Physical Science Texts This report reviews and critiques textbooks regarding scientific accuracy, accurate portrayal of the scientific approach, and the appropriateness and pedagogic effectiveness of the material for the particular grade level. From the Bookmarks, select "Textbooks" to see if yours is one of the 20 reviewed. Select "Suggestions for Middle School Teachers" to learn how to deal with inaccurate texts when your own expertise may not be physics.

The following three resources from How Stuff Works are in the Background Information Section because the advertisements on the pages might distract students. However, the articles, photos and illustrations are excellent and provide you with choices in how you approach your unit on forces, motion, and simple machines. You may decide to use just particular pieces from each of the resources, rather than any one in its entirety.

How Water Towers Work This article tells how forces and motion contribute to the technology involved in water tower design. Though there is no direct reference to simple machines, the concepts involved provide background needed to understand the relationship between forces, motion, work, and simple machines. Photos of unique water towers and a clear schematic of water tower design are included. Scroll down if the article title is not visible.

How Hydropower Plants Work Generation of electrical power starts with simple machines and forces. This site provides a comprehensible explanation of the sequence of events, forces and machines involved in the process. Photos and schematic drawings enhance the written explanation.

How Sewing Machines Work Though sewing machines are not simple machines, they rely on a combination of them as well as electricity. This article provides insight into the simple machines, the related technology, and the sewing machine’s impact on society. Since many middle schoolers are required to take a life skills class, which often includes experience with sewing machines, exploration of sewing machines could be complementary and synergistic for those students. Scroll down if the article title is not visible.

Nature and History of Technological Innovations

In this section, you will find famous historic innovators, who your students may perceive in a new light after their study. For example, is it accurate to call prehistoric people ignorant? Was Leonardo Da Vinci just an artist?

Technology at Work This guided discussion leads students to an understanding of what technology is and how long humans have been engaged with it. Students are asked to provide examples of technology and identify the 10 most important technological innovations in history. This exercise may serve as a segue into your unit.

Levers: Raising the Moai on Easter Island How were massive structures built by prehistoric people? There are no written records. However, scientists can make inferences and test their hypotheses as illustrated in this five-minute video clip. A background essay and discussion questions are included.

Exploring Leonardo This is the home site for the Museum of Science, Boston. Begin with the one-page Letter to Teachers to get oriented. The Inventor’s Workshop and Gadget Anatomy are appropriate sites your students can explore on their own, guided by your objectives.

Activities and Investigations

These activities allow students firsthand experience with simple machines, forces, motion, and work. You can adapt some to create performance assessments.

Simple Machines The purpose of this set of activities is to expose students to the usefulness of the six basic simple machines in today's world. At the end of this lesson, students will be able to (1) define the six simple machines, knowing how they differ or are similar in their use, (2) dissect a broken appliance or toy, listing all the parts found under the appropriate categories of simple machines, (3) read and interpret Rube Goldberg's drawings and design some of their own, and (4) design and build a working model, using three or more of the simple machines.

Simple Machine Scavenger Hunt This quick, easy, fun and effective activity can be done indoors or out. Students are charged with finding seven physical, three-dimensional simple machines. They must be able to classify and label the machines.

Simple Machines in Living Things

Simple machines are not restricted to the nonliving world. Here are two resources that highlight the importance of levers to humans. You may be able to find other activities that explore similar concepts in other living things like the jumping legs of frogs or the jaws of a predator.

Exploratorium: Sport Science This site provides creative materials to introduce physics to students and their teachers. Learn about the science behind a homerun, and find out how the physics of balance helps enthusiasts surf the waves. There are interviews, enticing images, and enthralling descriptions. Hands Up! integrates physics and biology in a physicist's first-person account of a tense rock climbing experience and is sure to keep students' attention. Students will recognize the various simple machines in the human body and their role in rock climbing.

SMARTR: Virtual Learning Experiences for Students

Visit our student site SMARTR to find related science-focused virtual learning experiences for your students! The SMARTR learning experiences were designed both for and by middle school aged students. Students from around the country participated in every stage of SMARTR’s development and each of the learning experiences includes multimedia content including videos, simulations, games and virtual activities.

Careers

The FunWorks Visit the FunWorks STEM career website for youth to learn more about a variety of science-related careers (click on the Science link at the bottom of the home page).

Latest Science News from the New York Times

NYT > Engineering and Engineers

News about Engineering and Engineers, including commentary and archival articles published in The New York Times.

NYT > U.S. Patent Office

News about U.S. Patent Office, including commentary and archival articles published in The New York Times.

National Science Education Standards

An exploration of simple machines meets the content standards of the National Science Education Standards in many areas: (a) Unifying Concepts and Processes, (b) Science as Inquiry, (c) Physical Science, (d) Life Science, (e) Science and Technology, and (f) History and Nature of Science.

For example, students may be required to build a compound machine, describe how each of Newton’s laws is manifested, and quantify the amount of work the machine can do. Students may be required to accomplish a given amount of work only—no more, no less—forcing them to think carefully about the technology they will use. What has been used in the past by other technologists? Can students use something similar or something better, not available to that historic technician?

An analysis of the work being accomplished requires students to recognize the system as a unit, its order, and organization as well as the individual parts of the whole. Their analysis requires initial measurements of the incoming forces and the distances over which the forces are applied as compared to the measured force out and distance over which the outcome force is applied. When students discover the forces are not exactly equal, what inferences can they offer?

Students may be required to find and describe simple machines in living things. What are they used for? How efficient are they? Does efficiency vary with species? What can account for that?

Excerpts from the Content standards appropriate to your work with middle school students appear below:

Physical Science: Content Standard B:

As a result of their activities in grades 5-8, all students should develop an understanding of:

  • Properties and changes of properties in matter
  • Motions and forces
  • Transfer of energy

Motions and Forces

  • The motion of an object can be described by its position, direction of motion, and speed. That motion can be measured and represented on a graph. (See Content Standard D (grades 5-8))
  • An object that is not being subjected to a force will continue to move at a constant speed and in a straight line.
  • If more than one force acts on an object along a straight line, then the forces will reinforce or cancel one another, depending on their direction and magnitude. Unbalanced forces will cause changes in the speed or direction of an object's motion.

Transfer of Energy

  • Energy is a property of many substances and is associated with heat, light, electricity, mechanical motion, sound, nuclei, and the nature of a chemical. Energy is transferred in many ways.
  • In most chemical and nuclear reactions, energy is transferred into or out of a system. Heat, light, mechanical motion, or electricity might all be involved in such transfers. (See Unifying Concepts and Processes)

Science and Technology: Content Standard E

As a result of activities in grades 5-8, all students should develop:

  • Abilities of technological design
  • Understandings about science and technology

Understandings about Science and Technology

  • Many different people in different cultures have made and continue to make contributions to science and technology.
  • Science and technology are reciprocal. Science helps drive technology, as it addresses questions that demand more sophisticated instruments and provides principles for better instrumentation and technique. Technology is essential to science, because it provides instruments and techniques that enable observations of objects and phenomena that are otherwise unobservable due to factors such as quantity, distance, location, size, and speed. Technology also provides tools for investigations, inquiry, and analysis.
  • Perfectly designed solutions do not exist. All technological solutions have trade-offs, such as safety, cost, efficiency, and appearance. Engineers often build in back-up systems to provide safety. Risk is part of living in a highly technological world. Reducing risk often results in new technology.
  • Technological designs have constraints. Some constraints are unavoidable, for example, properties of materials, or effects of weather and friction; other constraints limit choices in the design, for example, environmental protection, human safety, and aesthetics.

Content Standard F: Science in Personal and Social Perspectives

As a result of activities in grades 5-8, all students should develop understanding of:

  • Science and technology in society

Science and Technology in Society

  • Technology influences society through its products and processes. Technology influences the quality of life and the ways people act and interact. Technological changes are often accompanied by social, political, and economic changes that can be beneficial or detrimental to individuals and to society. Social needs, attitudes, and values influence the direction of technological development.
  • Science and technology have advanced through contributions of many different people, in different cultures, at different times in history. Science and technology have contributed enormously to economic growth and productivity among societies and groups within societies.

Read the entire National Science Education Standards online for free or register to download the free PDF. The content standards are found in Chapter 6.

Author and Copyright

Mary LeFever is a resource specialist for the Middle School Portal 2: Math & Science Pathways project, a doctoral candidate in science education at Ohio State University, and presently teaches high school biology. She has taught middle school science and biology and natural sciences at Columbus State Community College.

Please email any comments to msp@msteacher.org.

Connect with colleagues at our social network for middle school math and science teachers at http://msteacher2.org.

Copyright June 2007 - The Ohio State University. Last updated September 5, 2010. This material is based upon work supported by the National Science Foundation under Grant No. 0424671 and since September 1, 2009 Grant No. 0840824. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.