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**Gears**
Gears have many uses in our lives. They are used to: - multiply or reduce speed and force; - change the direction of motion; - transmit a force over a distance.

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Intermeshing gears are used to transmit motion and force. A series of intermeshing gears is called a **gear train.** Intermeshing gears turn in opposing directions. In a gear train we have a gear known as the //**driver**// and one known as the **//follower//**. //**Driver -**// is the gear that has the force or motion input. //**Follower -**// is the gear that results in the force or motion output. The above diagram shows a very simple gear train. Notice how the gears spin in opposite directions. If we were to turn the large gear (//**driver**//) we can multiply the number of turns generated by the smaller gear (//**follower**//).

We often talk about a //**gear ratio**//. The gear ratio of a gear train is the number of teeth on the follower divided by the number of teeth on the driver. In the gear train above the driver has 18 teeth while the follower has 8 teeth. Therefore the gear ratio is 8/18 or 4/9. For every 4 turns of the driver the follower turns 9 times. This gear train can be used to multiply speed on a bicycle if the follower was connected to a wheel and the driver connected to the paddles.

A simple rule applies. Low gear ratio = more speed = less force High gear ratio= less speed = more force.

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Student Challenge __ in a real life situation || Image of example of use || They turn when they do there job. || ||
 * Name of student || Example of use
 * Hussein || gears are manly used in cars and motorbikes. || [[image:.jpg]] ||
 * Kenny || Gears help to turn machines || [[image:Gears.jpg width="320" height="240"]] ||
 * Joseph || They make things go. || [[image:josephgears.jpg width="206" height="131"]] ||
 * William ||  || [[image:IMG_0110.JPG width="202" height="149"]] ||
 * Pashan || This help to uncork wine bottles. || [[image:SIMPLEMACHINE-GEARS.jpg]] ||
 * Zion || gears help your bicycle wheel spin. || [[image:chp_gears.jpg width="226" height="182"]] ||
 * Nicky ||  ||   ||
 * Rical || To open canned food || [[image:Opener.jpg width="173" height="138"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Matthew || g ||  ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Felix || Gears help things move like the gears on your bike. || [[image:gears_home.jpg width="155" height="227"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Wendell ||  ||   ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Tanaka || gears help go places like gearbikes || [[image:http://static.howstuffworks.com/gif/gear-bevel.jpg caption="http://static.howstuffworks.com/gif/gear-bevel.jpg"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Andrew || A gear is a big and small wheel that go around in a circle and both of them have a diffrent speed. || [[image:gear.jpg width="254" height="277"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Regan || this hepls things to move || [[image:http://www.coeshow.com/shop/images/uploads/CRF150-Gears.jpg width="236" height="196"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Haadi || A gear is a simple machine. || [[image:beavers-gears.jp.jpg width="240" height="213"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Wayne || These gears are used for bikes || [[image:DSC03045.JPG width="256" height="192"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Sky || these are gears || [[image:_skys_uesc_06_img0347.jpg]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Maya || When one gear turns, another gear turns with it. || [[image:mayaspur-gears.jpg]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Udita || This is an inside of a clock.The things in the pitures are called gears. || [[image:clock.jpg width="186" height="162"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Joy || some gears || [[image:gear.gif width="256" height="251"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Piper || Gears on a hand drill make the drillbit turn fast || <span style="font-family: Arial,Helvetica,sans-serif;">[[image:June_09_072.jpg width="172" height="133"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Bridget || There are some gears in the clock ||  ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Gloria || They can open canned food. || [[image:new_folder_006.jpg width="300" height="233"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Cassandra || Gears turn around to make things work. || [[image:gear1.jpg width="190" height="207"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Muneerah || Gears have teeth that can join together to make things move. ||  ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Keelan || Gears mainly have two wheels on them.
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Kezialine || My bike wheels have gears || [[image:100_3862.JPG width="326" height="240"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Anya ||  || [[image:can_opener.JPG width="297" height="195" caption="can opener"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Jasmine || Here are some small and big gears. || [[image:PS-22.jpg]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Joyce || Gears help move things. || [[image:gears.jpg width="228" height="246"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);">Astarlii || Gears are a type of wheel but they have little things called cogs . || [[image:Gears.jpg width="390" height="258"]] ||
 * <span style="background-color: rgb(253, 231, 186); color: rgb(70, 0, 128);"> ||  ||   ||