Discover - Building with Chains and Gears



Wheels and gears can work together and be connected in various ways.
Why are tracks such a good choice for tanks, bulldozers, and earthmovers?  Putting tracks on a vehicle is more expensive than using wheels and axles, so why do it?  If you are driving any of these vehicles, you cannot afford to be stuck in the mud, sand, or snow!

Look closely at the gear systems that drive powerful track vehicles such as bulldozers and tanks.  You will see that they are actually gears and chains.  The track is just a chain, except that it is wide and usually has teeth on the outside for grabbing the ground.  A chain is a way to connect two gears that are separated by a distance.


Gears do not always have to be for powerful things.  If you open any watch, you are bound to see tiny, delicate gears.  That's because gears are very good for speed changes, which allow the watchmaker to have good control over spin speed.  When you mesh two gears, you have made a gear train.  The gear that provides the power is the driving gear, and any other gear in the train is a driven gear.
If the driving gear is larger, the smaller driven gear will spin faster.  If the driving gear is smaller, the larger driven gear will spin slower.
The motor turns the small gear, so the small gear is the driving gear.  The larger gear is the driven gear.  The larger gear spins slower!  This train slows down.

  Video

Watch this video: By making gears smaller or larger, you can control how fast they spin.



In the next activity, you will practise building with gears, wheels, and chains to solve some engineering problems.

 Notebook: How can you solve engineering problems with gears, wheels and chains? 

  1. Click here to download this activity.
  2. Complete the activity and save it to your Machines Notebook.