Simple Machines & Work

Work - The Key Ideas

•Energy can be applied to matter.•Matter can be moved with force.•Mechanical advantage is the factor by which a machine multiplies the force put into it.

Work - Common Misconceptions

•Power is the same as force or work.

Reality: Power is the rate at which work is done.•The terms energy and force are interchangeable.

Reality: Energy is the capacity to do work, while force is a push or a pull that can cause an object to move or stop.

Work - Using DE Science Content

•Video Segment: Work, Force, and Energy•Exploration: Tote those Books•Interactive Video: Work and PowerVideo Segment: Work Defined

Work Review

Mechanical Advantage

Video - Mechanical Advantage

Video 2 - Mechanical Advantage

Reading passage

Simple Machines —The Key Ideas

• They all provide mechanical advantage• Can be used in a system.• Simple machines can be connected together in systems to

form complex machines.

Simple Machines—Prior Knowledge

Students often think of large, loud machines, but simple machines also provide mechanical advantage.

Review the Exploration Types of Simple Machines.

Simple Machines—Common Misconceptions

• A machine makes less work for people. – Reality: A machine does not decrease the amount of

work. Instead, a machine makes work easier by changing the size or direction of the force.

• A machine must have a motor. – Reality: A machine is a device that transmits and

modifies force. Such simple machines include the lever, inclined plane, wheel, pulley, wedge, and screw.

Lever—Using DE Science Content

• Resource 1, Video Segment: Lever• Resource 2, Video Segment: Three Classes of Levers• Resource 3, Exploration: Lever Ups and Downs• Resource 4, Interactive Video Segment: The Six Simple

Machines

Lever Information

Wheel & Axle - Using DE Science Content

•Video Segment: Wheel and Axle

•Reading Passage: Wheel and Axle

•Interactive Video Segment: The Six Simple Machines

Wheel & Axle Information

Wheel & Axle Misconception

A wheel makes less work for people.

Truth: In fact, a machine does not decrease the amount of work. Instead, machines such as the wheel and axle make the work easier by changing the size or direction of the force that needs to be applied.

Pulley - Using DE Science Content

•Video Segment: The Pulley•Image: Pulleys•Exploration: Pulleys at Work•Interactive Video: The Six Simple Machines

Pulley Information

Pulley - Common Misconception

Misconception: Pulleys always increase the amount of force

In fact, fixed pulleys do not increase the effort force; they only redirect it. Only moveable pulleys magnify the effort force.

Inclined Plane - Using DE Science Content

•Resource 1, Video Segment: Inclined Plane•Resource 2, Video Segment: The Inclined Plane and the Wedge•Resource 3, Interactive Video Segment: The Six Simple Machines

Inclined Plane

More information - Click on the inclined plane

Inclined Plane - Common Misconception

Misconception: An inclined plane means less work is used.

In fact, machines to not reduce the amount of work required. What they do is contribute to the input force or change its direction so that the input force required by people is reduced.

Wedge - Using DE science content

•Video Segment: Wedge•Video Segment: Apple Peeler•Interactive Video Segment: The Six Simple Machines

Wedge Information

Interactive wedge

Wedge Common Misconception

Misconception: A wedge is only used for things like door stops.

Fact: A door stop is a kind of wedge that pushes two things apart. However, wedges can also be used to split things. Any object with a cutting edge is considered a wedge.

Screw - Using DE Science Content

•Video Segment: Screw•Reading Passage: Screw•Video Segment: The ScrewInteractive Video Segment: The Six Simple Machines

Screw

Screw - Common Misconception

Misconception: Screws are only used a fasteners.

In fact, a screw can be used to lift and lower objects as well. A type of screw called an Archimedes screw is used to pump water for irrigation. Screws are also commonly used in systems as part of complex machines.