WARM UP: A world full of machines!

There are machines all around us!

Turn to your neighbor and discuss what kinds of machines you saw on your way to school today.

Make a list/draw 5-10 of them - LEFT p. 47.

Simple Machines Notes

Copy Words Copy Words andand Pictures! Pictures!

Machines Machines HelpHelp us Work us Work

Work is done when Work is done when something is something is moved a certain moved a certain distancedistance (d) (d) againstagainst a a forceforce (F) (F)

W=FdW=Fd

preAP

Pushing on a wallLifting Weights

Machines Machines HelHelp us Workp us Work

Work is done when Work is done when something is something is moved a certain moved a certain distancedistance (d) (d) against a against a forceforce (F) (F)

W=FdW=Fd

Most machines areMost machines areCompound MachinesCompound Machines

More than one simple machine More than one simple machine togethertogether

Simple Machine:Simple Machine:

Something that makes work Something that makes work easier to do with few or no easier to do with few or no moving parts.moving parts.

Pulleys and inclined planes Pulleys and inclined planes (ramps) are simple machines.(ramps) are simple machines.

PulleyInclined Plane

There are 6 There are 6 Simple Simple MachinesMachinesSM sortSM sort

Lever Pulley

Wheel and Axle Wedge

Screw

Inclined Plane

SM SortSM Sort

Each person received a machine Each person received a machine when you came into class. when you came into class.

Real-Real-world world ExampleExampless

Why do we Why do we need need

machines?machines?

Machines Machines helphelp us do work (make it us do work (make it easier)easier)-- the same amount of work we would have done anyway!

Machines Machines do notdo not do the work for us and do the work for us and they they do notdo not decrease the amount of decrease the amount of work! work! [Law of Conservation of Energy]

Machines change the Machines change the amount of effort amount of effort forceforce or the or the direction of the force direction of the force to to make work easier.make work easier.

If you wanted to get to point C on the If you wanted to get to point C on the illustration above, you have two options: illustration above, you have two options: start at A and go straight up, or start at B start at A and go straight up, or start at B and walk up the slope. Which is and walk up the slope. Which is easiereasier? ? Which requires Which requires more workmore work? ?

The only thing you have control over is if The only thing you have control over is if you put forth a lot of effort over a short you put forth a lot of effort over a short distance (situation A-C) or a little effort distance (situation A-C) or a little effort for a long distance (situation B-C). for a long distance (situation B-C).

Load/Resistance

Effort

Effort

Inclined Inclined PlanesPlanes

Also called a rampAs an inclined plane gets

shorter in height or longer in length, the amount of force necessary to move an object decreases.

PulleysPulleys

A pulley system consists of a rope attached to a grooved wheel and a load.

Pulleys put the weight of the load over different sections of the rope. They reduce the force needed to lift the load by increasing the distance the load is moved.

Effort

Load

The Load/ResistanceThe Load/Resistance

For all simple machines, an For all simple machines, an object's mass is related to the object's mass is related to the amount of force needed to amount of force needed to move it.move it.

BrainPOPBrainPOP

Inclined planesInclined planes PulleysPulleys

Review #1Review #1

________________________ are devices that make work easier. Simple machines have _______________________ parts. One example of the________________________ is a ramp, which helps you move something from a lower level to higher level. Another example is the ________________________, which is a grooved wheel with a rope around it.

Review #2Review #2

Inclined _____________________ and ____________________ reduce the amount of force that must be exerted on an object in order to ____________ it. The larger an object’s ________________, the larger the amount of ________________ needed to move it.

As an inclined plane ____________________in length, the amount of force necessary to move an object a certain height _____________________.

Stations 12 – See WSStations 12 – See WS

Kids assignmentKids assignment PulleysPulleys Spring scale, mass, etc.Spring scale, mass, etc.

ProjectProject

Your group must build a pulley and Your group must build a pulley and inclined plane system that moves inclined plane system that moves a payload from a payload from