List five simple machines that you or someone in your family uses to help make work easier around the house.

Bellwork: 2-27-2014

Objectives Differentiate between the six

simple machines. (SPI 0707.11.1)

Determine the amount of force needed to do work using different simple machines. (SPI 0707.11.2)

1. Complete the 2-square vocabulary activity in your scientist notebook with your group. Do the “yours” side for the 12 words/phrases above.

2. Complete the scenarios with your group. Write the explanations on your next blank page in your scientist notebook.

3. When you are finished, raise your hands and I will check your work.

Work hard, smart, and QUICKLY!!!

70. 2-Square Vocabulary

Bellwork 2-28-14 Get out Scientist Notebook and

continue working on the 2-square vocabulary and scenarios.

Objectives Differentiate between the six

simple machines. (SPI 0707.11.1)

Determine the amount of force needed to do work using different simple machines. (SPI 0707.11.2)

Machine YOURS: TEXTBOOK:

A machine is a device that makes work easier by changing the size or direction of a force.

Examples: wheelchair, scissors, chopsticks

Simple MachinesYOURS: TEXTBOOK:

A machine or simple device without moving parts.

Examples: lever, pulley, wheel & axle, inclined plane, wedge, screw

Work YOURS: TEXTBOOK:

Work is the transfer of energy to an object by using a force that causes the object to move in the direction of the force.

Work is done on an object if two things happen: 1) the object moves as a force is applied, 2) the direction of the object’s motion is the same as the direction of the force.

Examples: pushing a ball up a hill

Work or Not Work?OR ORYES NO YES NO

ForceYOURS: TEXTBOOK:

A push or a pull exerted on an object in order to change the motion of the object; force has size and direction.

Examples: people, bulldozer, static electricity

Work Input/Work Output

YOURS: TEXTBOOK: Work input is the

work done on the machine.

Work output is the work done by the machine.

Examples: opening a paint can

LeverYOURS: TEXTBOOK:

A lever is a simple machine that has a bar that pivots at a fixed point, called a fulcrum.

Examples: first-class lever (see saw), second-class lever (wheelbarrow or soda bottle opener), third-class lever (lifting weights or hammering a nail)

Three Classes of LeversFirst-Class Lever Second-Class Lever Third-Class Lever

Elementary School Middle School High School

Which of the following correctly explains why one of the above levers can lift the object with less effort force? A. Lever X will require less effort force because its fulcrum is closer

to the object than lever Y's fulcrum.B. Lever Y is a third-class lever and will require less effort force than

lever X, which is a second-class lever.C. Lever X is a third-class lever and will require less effort force than

lever Y, which is a second-class lever.D. Lever Y will require less effort force because its fulcrum is closer

to the input force than lever X's fulcrum.

Levers

PulleyYOURS: TEXTBOOK:

A simple machine that has a grooved wheel that holds a rope or a cable.

Examples: fixed, moveable, block and tackle

The pulley changes the direction of the force. Elevators make use of fixed pulleys.

Movable pulleys do increase force, but they also increase the distance over which the input force must be exerted.

A fixed pulley and a movable pulley are used together; the mechanical advantage of a block and tackle depends on the number of rope segments.

Which of the pulley systems shown below will lift the weight using the least amount of effort force?

Pulleys

Wheel & AxleYOURS: TEXTBOOK:

A simple machine consisting of two circular objects of different sizes.

Examples: car’s wheel & axle, faucet

Effort force applied to a wheel is ____________ when it is transferred to the axle because the axle travels a

___________ distance than the wheel.

A. multiplied, longer B. divided, longer C. multiplied, shorter D. divided, shorter

Wheel & Axle

Inclined PlaneYOURS: TEXTBOOK:

A simple machine that is a straight, slanted surface; a ramp.

Examples: ramp or slide

Tom wants to put a heavy box into the back of a moving truck. He is not strong enough to lift the box into the truck, so he uses a ramp to slide it up instead. The ramp is as an inclined plane that A. increases both the force needed to move the box and the distance

over which the force is applied.B. increases the force needed to move the box while decreasing the

distance over which the force is applied.C. decreases both the force needed to move the box and the distance

over which the force is applied.D. decreases the force needed to move the box while increasing the

distance over which the force is applied.

Inclined Plane

WedgeYOURS: TEXTBOOK:

A simple machine that is made up of two inclined planes and that moves; often used for cutting.

Examples: knife, axe, door stop

Select the choice that best completes the following sentence. When an axe is used to chop wood,

A. the axe blade acts as a wedge and changes the direction of the input force.B. the axe blade acts as a wedge and does not change the direction of the input

force.C. the axe blade acts as a lever and does not change the direction of the input force.D. the axe blade acts as a lever and changes the direction of the input force.

Wedge

Screw YOURS: TEXTBOOK:

A simple machine that consists of an inclined plane wrapped around a cylinder.

Examples: screw, light bulb

Which of the screws below requires the least amount of effort force to turn?

W. X. Z.Y.

Screws

Compound MachineYOURS: TEXTBOOK:

A machine made up of more than one simple machine.

Examples: manual can opener

YOURS: TEXTBOOK: A machine’s

mechanical advantage is the number of times the machine multiplies force; how much easier it is to do the work using that specific machine.

Examples:

Mechanical Advantage

It is 10 times easier to use a ramp to move a heavy object.