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# Objectives PowerPoint PPT Presentation

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

Objectives

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

### 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)

2-Square Vocabulary

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

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

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

• Work hard, smart, and QUICKLY!!!

### 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 Machines

YOURS:

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

or

OR

YES

NO

YES

NO

### Force

YOURS:

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

### Lever

YOURS:

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)

### Pulley

YOURS:

textbook:

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

• Examples: fixed, moveable, block and tackle

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.

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

### Pulleys

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

### Wheel & Axle

YOURS:

textbook:

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

• Examples: car’s wheel & axle, faucet

### Wheel & Axle

Effort force applied to a wheel is ____________ when it is transferred to the axle because the axle travels a ___________ distance than the wheel.

multiplied, longer

divided, longer

multiplied, shorter

divided, shorter

### Inclined Plane

YOURS:

textbook:

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

• Examples: ramp or slide

### Wedge

YOURS:

textbook:

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

• Examples: knife, axe, door stop

### Wedge

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

the axe blade acts as a wedge and changes the direction of the input force.

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

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

the axe blade acts as a lever and changes the direction of the input force.

### Screw

YOURS:

textbook:

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

• Examples: screw, light bulb

### Screws

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

X.

Y.

Z.

W.

### Compound Machine

YOURS:

textbook:

• A machine made up of more than one simple machine.

• Examples: manual can opener

YOURS:

textbook:

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

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:

Write the question & answer.

SCENARIOS

Fill out the chart as we go through the Simple Machines activity on the Edheads website.