How are gears connected by a chain is on a bicycle?

Answer 1

Just fine, thank you for asking.

The chain transfer power from where it's generated by the pedals to the rear wheel where it can push the bike forward.

The gears on a bike work just like any other set of gears, they allow you to trade power for travel - or the other way around. If spinning the pedals is too easy and you can't crank them round any faster, then a change of gears will make the rear wheel turn more WRT the pedals than before, bringing more resistance to the pedals and more speed to the bike. If turning the pedals is too heavy, then dropping a gear will make the pedals easier to turn on the cost of the rear wheel spinning a bit less for each turn of the pedals

Answer 2

Another muddled question. Some bikes have like a small gearbox inside the rear hub, in which case the chain only does two things: # it connects the sprocket by the pedals(called the chainwheel, or chain ring) to the single sprocket at the rear. # The front and rear sprockets are different in size in order to get the basic ratio between the pedalling speed and the bike's speed right. Some bikes have external gears by having several differently sized sprockets at the rear and 2-3 chainwheels at the front. In this case the chain has to be long enough and flexible enough to be able to move from one sprocket to another while riding. Moving the chain is done by running it through something called a derailer(or derailleur) which can push the chain sideways. The rear derailer also has two small sprockets that the chain is looped around to take up the slack.