Teacher's Folders

Saturday, May 28, 2011

Bike, the best form of transport


The bike is the most ecological and healthy form of transport that man has invented. Nowadays,in the world there are eight hundred millions of bikes, twice as much as cars. In Asia, millions of people are carried by bikes everyday. Nevertheless, in western countries, the popular "bikes" are used, especially, to do sport.
"THE BICYCLE"
The incorporation of two pedals to the primitive bike, caused the definitive take off of this gadget, and it began to be called "bicycle", it means, a two-wheel vehicle.

Pierre Michaux put the two pedals on the fr
ont wheel, and it forced him to make this wheel bigger (up to two metres in diameter), to get a balance speed.
But the problem appeared when the rider wanted to stop. Without brakes, the only option left was to do an acrobatic jump, that, unfortunately, most times, ended with a showy fall.


KINDS OF BIKES

-Road racing bikes: To achieve more speed, lighter materials, like titanium, are used, though they are expensive,

Moreover, to offer less resistance to the air, the bikes have aerodynamics profiles, low handlebars and lenticular wheels.

-Mountain bikes: the frame is strengthened and the wheels are expanded,

with the goal of going by through rough lands.

-Cross bikes: this bikes are similar to mountain bikes, but they are typical from EEUU. The frame is light, but strong,

attached to a wide handlebar and thick wheels, to be able to perform acrobatic jumps, wherever.

-High competition bikes: they are used by professional cyclists, especially on timed races. The gearshift is electronic, to avoid dropping the handlebar when

they are in full effort. New materials have halved the weight of this bikes!

-Ride bikes: they are a hybrid between mountain bikes and competition bikes.

They are adapted to circulate cormfortably through the streets. They have light and a boot.

-Other types of bikes: bikes that can be folded with small wheels,

which can go into the baggage, for example.

-Tandem bikes: tandems are bicycles built for two. The front rider (captain) controls the steering, braking, and shifting. The back rider (stoker) sometimes has limited access to brakes.

The pedals on a tandem are connected so that they revolve around the hub in unison. Tandems come in four subcategories: mountain, road, hybrid, and recumbent. These bikes feature the same characteristics as their namesake, but they're built for two riders

-Solar bikes: This futuristic model may become a serious alternative for the people who always go by car through the streets. This type of bike works with photovoltaic cells on the top of the bike.

If it’s cloudy, it doesn’t matter, because its batteries have a range of 4 km. Greenpeace has promised to test this new kind of bike!

Here is a link, if you want to look and search new information of the world of bikes...


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