# 3.2 - Force, Motion, and Energy: Simple Machines

The student will investigate and understand that the direction and size of force affects the motion of an object. Key ideas include

a)  multiple forces may act on an object;

• describe the relative size and direction of forces acting upon an object.  Bloom's Level: Analyze / Understand

b)  the net force on an object determines how an object moves;

• describe the relative size and direction of forces acting upon an object  Bloom's Level:  Understand Analyze
• plan and conduct an investigation concerning the effect forces have on an object's motion.  Bloom's Level: Understand

c)  simple machines increase or change the direction of a force; and

• explain how humans use machines to make work easier.  Bloom's Level:  Understand
• differentiate and classify the six types of simple machines (lever, inclined plane, wedge, wheel and axle, screw, and pulley) found in school and household items.  Bloom's Level: Analyze
• collaboratively plan an investigation to demonstrate the direction of the forces acting on a lever, pulley, and inclined plane as they relate to net forces.  Create a model labeling identified forces.   Bloom's Level: Apply / Create
• plan and conduct an experiment that compares the relative force required to move an object with and without the aid of a simple machine. Bloom's Level: Apply / Analyze
• identify a common task that might be easier if done with a simple machine.  Collaboratively design and build an apparatus that incorporates simple machines to accomplish the task.  Explain how the apparatus works and the importance of using simple machines.  Bloom's Level: Understand / Create

d)  simple and compound machines have many applications.

• explain how simple machines work together to form a compound machine.  Bloom's Level:  Understand
• identify compound machines and simple machines that comprise them within the school and household environment.  Bloom's Level: Understand

### BIG IDEAS

Forces between objects can cause a change in motion.

A machine is any device that helps people do work by changing the direction or the size of the force.

### UNDERSTANDING THE STANDARD

• Simple machines are tools that make work easier. Examples of tasks made easier include lifting a heavy weight, moving a heavy object over a distance, pushing things apart, changing the direction of a force, or holding an object together.
• The six simple machines are the lever, inclined plane, wedge, wheel and axle, screw, and pulley.
• The lever is a stiff bar that moves about a fixed point (fulcrum). It is a simple machine that is used to push, pull, or lift things. Examples include a seesaw, crowbar, and shovel.
• The inclined plane is a flat surface that is raised so one end is higher than the other. The inclined plane helps move heavy objects up or down. An example is a ramp.
• The wedge is wide at one end and pointed at the other to help cut or split other objects. Examples include a knife or ax.
• The wheel and axle consists of a rod attached to a wheel. A wheel and axle makes it easier to move or turn things. Examples include bicycle wheels, roller skates, and a door knob.
• The screw is an inclined plane wrapped around a cylinder or cone. A common use of the screw is to hold objects together. Examples include a jar lid and wood screw.
• The pulley is a wheel that has a rope wrapped around it. Pulleys can be used to lift heavy objects by changing the direction or amount of the force. Examples include a flagpole.
• A compound machine is a combination of two or more simple machines. Examples include scissors, wheelbarrow, and bicycle.

### ESSENTIALS

Essential Questions:

·  How does a scientist describe work?

·  How do we use machines in our every day lives?

·  Why do machines do work?

·  How do simple machines combine to make work easier?

In order to meet this standard, it is expected that students will

• identify and differentiate the six types of simple machines: lever, screw, pulley, wheel and axle, inclined plane, and wedge.
• differentiate and classify specific examples of simple machines found in school and household items. These include a screwdriver, nutcracker, screw, flagpole pulley, ramp, and seesaw.
• analyze the application of and explain the function of each of the six types of simple machines. An example would be that an inclined plane is a ramp to make it easier for a heavy object to be moved up or down.
• identify and classify the simple machines which compose a compound machine, such as scissors, wheelbarrow, and bicycle.
• design and construct an apparatus that contains a simple machine.

### KEY VOCABULARY

ax

bicycle

classify

compound machine

construct

crowbar

design

differentiate

flagpole

force

fulcrum

function

identify

inclined plane

lever

move

nutcracker

pulley

pulley

pulling

pushing

ramp

scissors

screw

screwdriver

seesaw

simple machine

wedge

wheel and axle

wheelbarrow

work

Updated: Jun 18, 2019