Work and Machines

This unit introduces the topics of force, work, and simple machines such as the lever, inclined plane, and pulley. This introduction to simple machines is explained using the focus words: machine, work, force, specifications, lever, exert, effort, apply, and load. These critical terms are used in middle school and high school physics classes.

Activities

Scene: Machines Everywhere

Cooper, Olivia, and Hamza help one another with their homework on simple machines and the physics sense of work, effort, and force and how they are measured. The script talks about pulleys in elevators and simple ways to think about work at a book fair.

Duration: Approximately 50 minutes

Lab: The Clever Lever

Discover what makes levers so clever by focusing on this simple machine. This activity investigates three types of levers. Student construct three levers–one for each class of lever–and reflect on the amount of force required, and work produced, by each lever.

Duration: Approximately 45 minutes

Lesson: Work in and Work Out

Students apply the concepts work, force, and distance to a model of a bike climbing two hills, in order to understand how the concepts relate.

Duration: Approximately 25 minutes

Lesson: A Closer Look at Levers

We're surrounded by levers! They don't always look like a seesaw or a catapult, however. Students review the concepts of effort, fulcrum, and load so they can see levers wherever they appear.

Duration: Approximately 60 minutes

Lab: The Helpful Pulley

Students collect and analyze data on force and distance needed to move a load in a pulley system. Students explore how pulleys work by building them!

Duration: Approximately 60 minutes

Writing: Fairness on the Job Site

Students use science to help a supervisor decide on the fairest way to pay construction workers for their work. Students apply the unit's concepts to writing a persuasive essay about the desirability of paying extra to workers who use a more efficient lever.

Duration: Approximately 30 minutes

Teacher Tune-ups

• How is the word “work” used in the sciences?
• What are the different classes of levers?

Student View of Visuals and Activities

Some teachers prefer to have students view the slides and other visual assets in this unit directly instead of projecting them in class. Below is a web page to share with students with links to some of same items that are within in the teacher lesson plans, but without the explanatory text for the teacher.

 

• Student Links to Unit E2 Slides and Other Visuals

Original SciGen Unit

This unit has been adapted from "8.2 Work and Machines" in the Word Generation program led by Catherine Snow (Harvard University) through a SERP collaboration with the Boston Public Schools and other districts in Massachusetts and Maryland.

PDFs of that earlier unit's teacher and student editions are available at the Science Generation Download Center.

machine

noun – a device that changes the magnitude or direction of a force

How is a lever a machine?

work

noun – energy transferred by force acting over a distance

Work is calculated by multiplying force and distance. What unit describes work? (It starts with a “J.”)

lever

noun – a machine that has a rigid fixed beam and a fulcrum

How is a baseball bat a lever? How about a wheelbarrow?

exert

verb – to apply or put forth

When you kick a ball, you exert a force upon it. What are other sports examples of exerting force?

apply

verb – to exert, to implement

Do you apply more effort to your friendships or hobbies? Explain.

load

noun – a weight or source of pressure

How does moving the fulcrum on a lever affect the load?

force

noun – a push or pull on an object

Explain how the force of gravity is a major factor in the way our planet orbits the Sun.

effort

noun – a force exerted by a machine (or human)

How do the locations of the effort, load, and fulcrum determine the class of lever?

specifications

noun – a description of the design and materials of a system

The specifications of how to build bombs and other illegal items are on the internet. Do you think posting such information should be illegal?